Merge pull request #16507 from markdroth/health_checking_client

Health checking client

38 files changed, 1791 insertions, 508 deletions

diff --git a/.clang_complete b/.clang_complete
index aa77554f4e..1448b01342 100644
--- a/.clang_complete
+++ b/.clang_complete
@@ -14,4 +14,5 @@
 -Ithird_party/cares
 -Ithird_party/googletest/googletest/include
 -Ithird_party/googletest/googlemock/include
+-Ithird_party/nanopb
 
diff --git a/BUILD b/BUILD
index e39d03b293..65cd4715f1 100644
--- a/BUILD
+++ b/BUILD
@@ -131,7 +131,6 @@ GRPCXX_SRCS = [
     "src/cpp/server/create_default_thread_pool.cc",
     "src/cpp/server/dynamic_thread_pool.cc",
     "src/cpp/server/health/default_health_check_service.cc",
-    "src/cpp/server/health/health.pb.c",
     "src/cpp/server/health/health_check_service.cc",
     "src/cpp/server/health/health_check_service_server_builder_option.cc",
     "src/cpp/server/server_builder.cc",
@@ -151,7 +150,6 @@ GRPCXX_HDRS = [
     "src/cpp/common/channel_filter.h",
     "src/cpp/server/dynamic_thread_pool.h",
     "src/cpp/server/health/default_health_check_service.h",
-    "src/cpp/server/health/health.pb.h",
     "src/cpp/server/thread_pool_interface.h",
     "src/cpp/thread_manager/thread_manager.h",
 ]
@@ -1040,6 +1038,7 @@ grpc_cc_library(
         "src/core/ext/filters/client_channel/client_channel_factory.cc",
         "src/core/ext/filters/client_channel/client_channel_plugin.cc",
         "src/core/ext/filters/client_channel/connector.cc",
+        "src/core/ext/filters/client_channel/health/health_check_client.cc",
         "src/core/ext/filters/client_channel/http_connect_handshaker.cc",
         "src/core/ext/filters/client_channel/http_proxy.cc",
         "src/core/ext/filters/client_channel/lb_policy.cc",
@@ -1062,6 +1061,7 @@ grpc_cc_library(
         "src/core/ext/filters/client_channel/client_channel_channelz.h",
         "src/core/ext/filters/client_channel/client_channel_factory.h",
         "src/core/ext/filters/client_channel/connector.h",
+        "src/core/ext/filters/client_channel/health/health_check_client.h",
         "src/core/ext/filters/client_channel/http_connect_handshaker.h",
         "src/core/ext/filters/client_channel/http_proxy.h",
         "src/core/ext/filters/client_channel/lb_policy.h",
@@ -1089,6 +1089,7 @@ grpc_cc_library(
         "orphanable",
         "ref_counted",
         "ref_counted_ptr",
+        "health_proto",
     ],
 )
 
@@ -1201,6 +1202,20 @@ grpc_cc_library(
 )
 
 grpc_cc_library(
+    name = "health_proto",
+    srcs = [
+        "src/core/ext/filters/client_channel/health/health.pb.c",
+    ],
+    hdrs = [
+        "src/core/ext/filters/client_channel/health/health.pb.h",
+    ],
+    external_deps = [
+        "nanopb",
+    ],
+    language = "c++",
+)
+
+grpc_cc_library(
     name = "grpclb_proto",
     srcs = [
         "src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/google/protobuf/duration.pb.c",
@@ -1993,6 +2008,7 @@ grpc_cc_library(
     deps = [
         "grpc",
         "grpc++_codegen_base",
+        "health_proto",
     ],
 )
 
@@ -2005,6 +2021,7 @@ grpc_cc_library(
     deps = [
         "grpc++_codegen_base",
         "grpc_unsecure",
+        "health_proto",
     ],
 )
 
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3edc59d1dd..23ef8b3b64 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1231,6 +1231,7 @@ add_library(grpc
   src/core/ext/filters/client_channel/client_channel_factory.cc
   src/core/ext/filters/client_channel/client_channel_plugin.cc
   src/core/ext/filters/client_channel/connector.cc
+  src/core/ext/filters/client_channel/health/health_check_client.cc
   src/core/ext/filters/client_channel/http_connect_handshaker.cc
   src/core/ext/filters/client_channel/http_proxy.cc
   src/core/ext/filters/client_channel/lb_policy.cc
@@ -1247,6 +1248,7 @@ add_library(grpc
   src/core/ext/filters/client_channel/subchannel_index.cc
   src/core/ext/filters/client_channel/uri_parser.cc
   src/core/ext/filters/deadline/deadline_filter.cc
+  src/core/ext/filters/client_channel/health/health.pb.c
   src/core/tsi/alts_transport_security.cc
   src/core/tsi/fake_transport_security.cc
   src/core/tsi/local_transport_security.cc
@@ -1581,6 +1583,7 @@ add_library(grpc_cronet
   src/core/ext/filters/client_channel/client_channel_factory.cc
   src/core/ext/filters/client_channel/client_channel_plugin.cc
   src/core/ext/filters/client_channel/connector.cc
+  src/core/ext/filters/client_channel/health/health_check_client.cc
   src/core/ext/filters/client_channel/http_connect_handshaker.cc
   src/core/ext/filters/client_channel/http_proxy.cc
   src/core/ext/filters/client_channel/lb_policy.cc
@@ -1597,6 +1600,10 @@ add_library(grpc_cronet
   src/core/ext/filters/client_channel/subchannel_index.cc
   src/core/ext/filters/client_channel/uri_parser.cc
   src/core/ext/filters/deadline/deadline_filter.cc
+  src/core/ext/filters/client_channel/health/health.pb.c
+  third_party/nanopb/pb_common.c
+  third_party/nanopb/pb_decode.c
+  third_party/nanopb/pb_encode.c
   src/core/lib/http/httpcli_security_connector.cc
   src/core/lib/security/context/security_context.cc
   src/core/lib/security/credentials/alts/alts_credentials.cc
@@ -1661,9 +1668,6 @@ add_library(grpc_cronet
   src/core/tsi/alts/handshaker/altscontext.pb.c
   src/core/tsi/alts/handshaker/handshaker.pb.c
   src/core/tsi/alts/handshaker/transport_security_common.pb.c
-  third_party/nanopb/pb_common.c
-  third_party/nanopb/pb_decode.c
-  third_party/nanopb/pb_encode.c
   src/core/tsi/transport_security.cc
   src/core/ext/transport/chttp2/client/insecure/channel_create.cc
   src/core/ext/transport/chttp2/client/insecure/channel_create_posix.cc
@@ -1951,6 +1955,7 @@ add_library(grpc_test_util
   src/core/ext/filters/client_channel/client_channel_factory.cc
   src/core/ext/filters/client_channel/client_channel_plugin.cc
   src/core/ext/filters/client_channel/connector.cc
+  src/core/ext/filters/client_channel/health/health_check_client.cc
   src/core/ext/filters/client_channel/http_connect_handshaker.cc
   src/core/ext/filters/client_channel/http_proxy.cc
   src/core/ext/filters/client_channel/lb_policy.cc
@@ -1967,6 +1972,10 @@ add_library(grpc_test_util
   src/core/ext/filters/client_channel/subchannel_index.cc
   src/core/ext/filters/client_channel/uri_parser.cc
   src/core/ext/filters/deadline/deadline_filter.cc
+  src/core/ext/filters/client_channel/health/health.pb.c
+  third_party/nanopb/pb_common.c
+  third_party/nanopb/pb_decode.c
+  third_party/nanopb/pb_encode.c
   src/core/ext/transport/chttp2/transport/bin_decoder.cc
   src/core/ext/transport/chttp2/transport/bin_encoder.cc
   src/core/ext/transport/chttp2/transport/chttp2_plugin.cc
@@ -2265,6 +2274,7 @@ add_library(grpc_test_util_unsecure
   src/core/ext/filters/client_channel/client_channel_factory.cc
   src/core/ext/filters/client_channel/client_channel_plugin.cc
   src/core/ext/filters/client_channel/connector.cc
+  src/core/ext/filters/client_channel/health/health_check_client.cc
   src/core/ext/filters/client_channel/http_connect_handshaker.cc
   src/core/ext/filters/client_channel/http_proxy.cc
   src/core/ext/filters/client_channel/lb_policy.cc
@@ -2281,6 +2291,10 @@ add_library(grpc_test_util_unsecure
   src/core/ext/filters/client_channel/subchannel_index.cc
   src/core/ext/filters/client_channel/uri_parser.cc
   src/core/ext/filters/deadline/deadline_filter.cc
+  src/core/ext/filters/client_channel/health/health.pb.c
+  third_party/nanopb/pb_common.c
+  third_party/nanopb/pb_decode.c
+  third_party/nanopb/pb_encode.c
   src/core/ext/transport/chttp2/transport/bin_decoder.cc
   src/core/ext/transport/chttp2/transport/bin_encoder.cc
   src/core/ext/transport/chttp2/transport/chttp2_plugin.cc
@@ -2592,6 +2606,7 @@ add_library(grpc_unsecure
   src/core/ext/filters/client_channel/client_channel_factory.cc
   src/core/ext/filters/client_channel/client_channel_plugin.cc
   src/core/ext/filters/client_channel/connector.cc
+  src/core/ext/filters/client_channel/health/health_check_client.cc
   src/core/ext/filters/client_channel/http_connect_handshaker.cc
   src/core/ext/filters/client_channel/http_proxy.cc
   src/core/ext/filters/client_channel/lb_policy.cc
@@ -2608,6 +2623,10 @@ add_library(grpc_unsecure
   src/core/ext/filters/client_channel/subchannel_index.cc
   src/core/ext/filters/client_channel/uri_parser.cc
   src/core/ext/filters/deadline/deadline_filter.cc
+  src/core/ext/filters/client_channel/health/health.pb.c
+  third_party/nanopb/pb_common.c
+  third_party/nanopb/pb_decode.c
+  third_party/nanopb/pb_encode.c
   src/core/ext/transport/inproc/inproc_plugin.cc
   src/core/ext/transport/inproc/inproc_transport.cc
   src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc
@@ -2626,9 +2645,6 @@ add_library(grpc_unsecure
   src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel.cc
   src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_client_stats.cc
   src/core/ext/filters/client_channel/lb_policy/grpclb/load_balancer_api.cc
-  third_party/nanopb/pb_common.c
-  third_party/nanopb/pb_decode.c
-  third_party/nanopb/pb_encode.c
   src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/google/protobuf/duration.pb.c
   src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/google/protobuf/timestamp.pb.c
   src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c
@@ -2862,7 +2878,6 @@ add_library(grpc++
   src/cpp/server/create_default_thread_pool.cc
   src/cpp/server/dynamic_thread_pool.cc
   src/cpp/server/health/default_health_check_service.cc
-  src/cpp/server/health/health.pb.c
   src/cpp/server/health/health_check_service.cc
   src/cpp/server/health/health_check_service_server_builder_option.cc
   src/cpp/server/server_builder.cc
@@ -2875,6 +2890,10 @@ add_library(grpc++
   src/cpp/util/status.cc
   src/cpp/util/string_ref.cc
   src/cpp/util/time_cc.cc
+  src/core/ext/filters/client_channel/health/health.pb.c
+  third_party/nanopb/pb_common.c
+  third_party/nanopb/pb_decode.c
+  third_party/nanopb/pb_encode.c
   src/cpp/codegen/codegen_init.cc
 )
 
@@ -3223,7 +3242,6 @@ add_library(grpc++_cronet
   src/cpp/server/create_default_thread_pool.cc
   src/cpp/server/dynamic_thread_pool.cc
   src/cpp/server/health/default_health_check_service.cc
-  src/cpp/server/health/health.pb.c
   src/cpp/server/health/health_check_service.cc
   src/cpp/server/health/health_check_service_server_builder_option.cc
   src/cpp/server/server_builder.cc
@@ -3236,6 +3254,10 @@ add_library(grpc++_cronet
   src/cpp/util/status.cc
   src/cpp/util/string_ref.cc
   src/cpp/util/time_cc.cc
+  src/core/ext/filters/client_channel/health/health.pb.c
+  third_party/nanopb/pb_common.c
+  third_party/nanopb/pb_decode.c
+  third_party/nanopb/pb_encode.c
   src/cpp/codegen/codegen_init.cc
   src/core/ext/transport/chttp2/client/insecure/channel_create.cc
   src/core/ext/transport/chttp2/client/insecure/channel_create_posix.cc
@@ -3426,6 +3448,7 @@ add_library(grpc++_cronet
   src/core/ext/filters/client_channel/client_channel_factory.cc
   src/core/ext/filters/client_channel/client_channel_plugin.cc
   src/core/ext/filters/client_channel/connector.cc
+  src/core/ext/filters/client_channel/health/health_check_client.cc
   src/core/ext/filters/client_channel/http_connect_handshaker.cc
   src/core/ext/filters/client_channel/http_proxy.cc
   src/core/ext/filters/client_channel/lb_policy.cc
@@ -4346,7 +4369,6 @@ add_library(grpc++_unsecure
   src/cpp/server/create_default_thread_pool.cc
   src/cpp/server/dynamic_thread_pool.cc
   src/cpp/server/health/default_health_check_service.cc
-  src/cpp/server/health/health.pb.c
   src/cpp/server/health/health_check_service.cc
   src/cpp/server/health/health_check_service_server_builder_option.cc
   src/cpp/server/server_builder.cc
@@ -4359,6 +4381,10 @@ add_library(grpc++_unsecure
   src/cpp/util/status.cc
   src/cpp/util/string_ref.cc
   src/cpp/util/time_cc.cc
+  src/core/ext/filters/client_channel/health/health.pb.c
+  third_party/nanopb/pb_common.c
+  third_party/nanopb/pb_decode.c
+  third_party/nanopb/pb_encode.c
   src/cpp/codegen/codegen_init.cc
 )
 
diff --git a/Makefile b/Makefile
index 42166082b0..d0a3f86383 100644
--- a/Makefile
+++ b/Makefile
@@ -3698,6 +3698,7 @@ LIBGRPC_SRC = \
     src/core/ext/filters/client_channel/client_channel_factory.cc \
     src/core/ext/filters/client_channel/client_channel_plugin.cc \
     src/core/ext/filters/client_channel/connector.cc \
+    src/core/ext/filters/client_channel/health/health_check_client.cc \
     src/core/ext/filters/client_channel/http_connect_handshaker.cc \
     src/core/ext/filters/client_channel/http_proxy.cc \
     src/core/ext/filters/client_channel/lb_policy.cc \
@@ -3714,6 +3715,7 @@ LIBGRPC_SRC = \
     src/core/ext/filters/client_channel/subchannel_index.cc \
     src/core/ext/filters/client_channel/uri_parser.cc \
     src/core/ext/filters/deadline/deadline_filter.cc \
+    src/core/ext/filters/client_channel/health/health.pb.c \
     src/core/tsi/alts_transport_security.cc \
     src/core/tsi/fake_transport_security.cc \
     src/core/tsi/local_transport_security.cc \
@@ -4042,6 +4044,7 @@ LIBGRPC_CRONET_SRC = \
     src/core/ext/filters/client_channel/client_channel_factory.cc \
     src/core/ext/filters/client_channel/client_channel_plugin.cc \
     src/core/ext/filters/client_channel/connector.cc \
+    src/core/ext/filters/client_channel/health/health_check_client.cc \
     src/core/ext/filters/client_channel/http_connect_handshaker.cc \
     src/core/ext/filters/client_channel/http_proxy.cc \
     src/core/ext/filters/client_channel/lb_policy.cc \
@@ -4058,6 +4061,10 @@ LIBGRPC_CRONET_SRC = \
     src/core/ext/filters/client_channel/subchannel_index.cc \
     src/core/ext/filters/client_channel/uri_parser.cc \
     src/core/ext/filters/deadline/deadline_filter.cc \
+    src/core/ext/filters/client_channel/health/health.pb.c \
+    third_party/nanopb/pb_common.c \
+    third_party/nanopb/pb_decode.c \
+    third_party/nanopb/pb_encode.c \
     src/core/lib/http/httpcli_security_connector.cc \
     src/core/lib/security/context/security_context.cc \
     src/core/lib/security/credentials/alts/alts_credentials.cc \
@@ -4122,9 +4129,6 @@ LIBGRPC_CRONET_SRC = \
     src/core/tsi/alts/handshaker/altscontext.pb.c \
     src/core/tsi/alts/handshaker/handshaker.pb.c \
     src/core/tsi/alts/handshaker/transport_security_common.pb.c \
-    third_party/nanopb/pb_common.c \
-    third_party/nanopb/pb_decode.c \
-    third_party/nanopb/pb_encode.c \
     src/core/tsi/transport_security.cc \
     src/core/ext/transport/chttp2/client/insecure/channel_create.cc \
     src/core/ext/transport/chttp2/client/insecure/channel_create_posix.cc \
@@ -4405,6 +4409,7 @@ LIBGRPC_TEST_UTIL_SRC = \
     src/core/ext/filters/client_channel/client_channel_factory.cc \
     src/core/ext/filters/client_channel/client_channel_plugin.cc \
     src/core/ext/filters/client_channel/connector.cc \
+    src/core/ext/filters/client_channel/health/health_check_client.cc \
     src/core/ext/filters/client_channel/http_connect_handshaker.cc \
     src/core/ext/filters/client_channel/http_proxy.cc \
     src/core/ext/filters/client_channel/lb_policy.cc \
@@ -4421,6 +4426,10 @@ LIBGRPC_TEST_UTIL_SRC = \
     src/core/ext/filters/client_channel/subchannel_index.cc \
     src/core/ext/filters/client_channel/uri_parser.cc \
     src/core/ext/filters/deadline/deadline_filter.cc \
+    src/core/ext/filters/client_channel/health/health.pb.c \
+    third_party/nanopb/pb_common.c \
+    third_party/nanopb/pb_decode.c \
+    third_party/nanopb/pb_encode.c \
     src/core/ext/transport/chttp2/transport/bin_decoder.cc \
     src/core/ext/transport/chttp2/transport/bin_encoder.cc \
     src/core/ext/transport/chttp2/transport/chttp2_plugin.cc \
@@ -4705,6 +4714,7 @@ LIBGRPC_TEST_UTIL_UNSECURE_SRC = \
     src/core/ext/filters/client_channel/client_channel_factory.cc \
     src/core/ext/filters/client_channel/client_channel_plugin.cc \
     src/core/ext/filters/client_channel/connector.cc \
+    src/core/ext/filters/client_channel/health/health_check_client.cc \
     src/core/ext/filters/client_channel/http_connect_handshaker.cc \
     src/core/ext/filters/client_channel/http_proxy.cc \
     src/core/ext/filters/client_channel/lb_policy.cc \
@@ -4721,6 +4731,10 @@ LIBGRPC_TEST_UTIL_UNSECURE_SRC = \
     src/core/ext/filters/client_channel/subchannel_index.cc \
     src/core/ext/filters/client_channel/uri_parser.cc \
     src/core/ext/filters/deadline/deadline_filter.cc \
+    src/core/ext/filters/client_channel/health/health.pb.c \
+    third_party/nanopb/pb_common.c \
+    third_party/nanopb/pb_decode.c \
+    third_party/nanopb/pb_encode.c \
     src/core/ext/transport/chttp2/transport/bin_decoder.cc \
     src/core/ext/transport/chttp2/transport/bin_encoder.cc \
     src/core/ext/transport/chttp2/transport/chttp2_plugin.cc \
@@ -5005,6 +5019,7 @@ LIBGRPC_UNSECURE_SRC = \
     src/core/ext/filters/client_channel/client_channel_factory.cc \
     src/core/ext/filters/client_channel/client_channel_plugin.cc \
     src/core/ext/filters/client_channel/connector.cc \
+    src/core/ext/filters/client_channel/health/health_check_client.cc \
     src/core/ext/filters/client_channel/http_connect_handshaker.cc \
     src/core/ext/filters/client_channel/http_proxy.cc \
     src/core/ext/filters/client_channel/lb_policy.cc \
@@ -5021,6 +5036,10 @@ LIBGRPC_UNSECURE_SRC = \
     src/core/ext/filters/client_channel/subchannel_index.cc \
     src/core/ext/filters/client_channel/uri_parser.cc \
     src/core/ext/filters/deadline/deadline_filter.cc \
+    src/core/ext/filters/client_channel/health/health.pb.c \
+    third_party/nanopb/pb_common.c \
+    third_party/nanopb/pb_decode.c \
+    third_party/nanopb/pb_encode.c \
     src/core/ext/transport/inproc/inproc_plugin.cc \
     src/core/ext/transport/inproc/inproc_transport.cc \
     src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc \
@@ -5039,9 +5058,6 @@ LIBGRPC_UNSECURE_SRC = \
     src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel.cc \
     src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_client_stats.cc \
     src/core/ext/filters/client_channel/lb_policy/grpclb/load_balancer_api.cc \
-    third_party/nanopb/pb_common.c \
-    third_party/nanopb/pb_decode.c \
-    third_party/nanopb/pb_encode.c \
     src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/google/protobuf/duration.pb.c \
     src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/google/protobuf/timestamp.pb.c \
     src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c \
@@ -5240,7 +5256,6 @@ LIBGRPC++_SRC = \
     src/cpp/server/create_default_thread_pool.cc \
     src/cpp/server/dynamic_thread_pool.cc \
     src/cpp/server/health/default_health_check_service.cc \
-    src/cpp/server/health/health.pb.c \
     src/cpp/server/health/health_check_service.cc \
     src/cpp/server/health/health_check_service_server_builder_option.cc \
     src/cpp/server/server_builder.cc \
@@ -5253,6 +5268,10 @@ LIBGRPC++_SRC = \
     src/cpp/util/status.cc \
     src/cpp/util/string_ref.cc \
     src/cpp/util/time_cc.cc \
+    src/core/ext/filters/client_channel/health/health.pb.c \
+    third_party/nanopb/pb_common.c \
+    third_party/nanopb/pb_decode.c \
+    third_party/nanopb/pb_encode.c \
     src/cpp/codegen/codegen_init.cc \
 
 PUBLIC_HEADERS_CXX += \
@@ -5611,7 +5630,6 @@ LIBGRPC++_CRONET_SRC = \
     src/cpp/server/create_default_thread_pool.cc \
     src/cpp/server/dynamic_thread_pool.cc \
     src/cpp/server/health/default_health_check_service.cc \
-    src/cpp/server/health/health.pb.c \
     src/cpp/server/health/health_check_service.cc \
     src/cpp/server/health/health_check_service_server_builder_option.cc \
     src/cpp/server/server_builder.cc \
@@ -5624,6 +5642,10 @@ LIBGRPC++_CRONET_SRC = \
     src/cpp/util/status.cc \
     src/cpp/util/string_ref.cc \
     src/cpp/util/time_cc.cc \
+    src/core/ext/filters/client_channel/health/health.pb.c \
+    third_party/nanopb/pb_common.c \
+    third_party/nanopb/pb_decode.c \
+    third_party/nanopb/pb_encode.c \
     src/cpp/codegen/codegen_init.cc \
     src/core/ext/transport/chttp2/client/insecure/channel_create.cc \
     src/core/ext/transport/chttp2/client/insecure/channel_create_posix.cc \
@@ -5814,6 +5836,7 @@ LIBGRPC++_CRONET_SRC = \
     src/core/ext/filters/client_channel/client_channel_factory.cc \
     src/core/ext/filters/client_channel/client_channel_plugin.cc \
     src/core/ext/filters/client_channel/connector.cc \
+    src/core/ext/filters/client_channel/health/health_check_client.cc \
     src/core/ext/filters/client_channel/http_connect_handshaker.cc \
     src/core/ext/filters/client_channel/http_proxy.cc \
     src/core/ext/filters/client_channel/lb_policy.cc \
@@ -6699,7 +6722,6 @@ LIBGRPC++_UNSECURE_SRC = \
     src/cpp/server/create_default_thread_pool.cc \
     src/cpp/server/dynamic_thread_pool.cc \
     src/cpp/server/health/default_health_check_service.cc \
-    src/cpp/server/health/health.pb.c \
     src/cpp/server/health/health_check_service.cc \
     src/cpp/server/health/health_check_service_server_builder_option.cc \
     src/cpp/server/server_builder.cc \
@@ -6712,6 +6734,10 @@ LIBGRPC++_UNSECURE_SRC = \
     src/cpp/util/status.cc \
     src/cpp/util/string_ref.cc \
     src/cpp/util/time_cc.cc \
+    src/core/ext/filters/client_channel/health/health.pb.c \
+    third_party/nanopb/pb_common.c \
+    third_party/nanopb/pb_decode.c \
+    third_party/nanopb/pb_encode.c \
     src/cpp/codegen/codegen_init.cc \
 
 PUBLIC_HEADERS_CXX += \
diff --git a/build.yaml b/build.yaml
index 42addc4014..d8d51c1b94 100644
--- a/build.yaml
+++ b/build.yaml
@@ -572,6 +572,7 @@ filegroups:
   - src/core/ext/filters/client_channel/client_channel_channelz.h
   - src/core/ext/filters/client_channel/client_channel_factory.h
   - src/core/ext/filters/client_channel/connector.h
+  - src/core/ext/filters/client_channel/health/health_check_client.h
   - src/core/ext/filters/client_channel/http_connect_handshaker.h
   - src/core/ext/filters/client_channel/http_proxy.h
   - src/core/ext/filters/client_channel/lb_policy.h
@@ -596,6 +597,7 @@ filegroups:
   - src/core/ext/filters/client_channel/client_channel_factory.cc
   - src/core/ext/filters/client_channel/client_channel_plugin.cc
   - src/core/ext/filters/client_channel/connector.cc
+  - src/core/ext/filters/client_channel/health/health_check_client.cc
   - src/core/ext/filters/client_channel/http_connect_handshaker.cc
   - src/core/ext/filters/client_channel/http_proxy.cc
   - src/core/ext/filters/client_channel/lb_policy.cc
@@ -615,6 +617,7 @@ filegroups:
   uses:
   - grpc_base
   - grpc_deadline_filter
+  - health_proto
 - name: grpc_codegen
   public_headers:
   - include/grpc/impl/codegen/byte_buffer.h
@@ -1113,6 +1116,13 @@ filegroups:
   - src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c
   uses:
   - nanopb
+- name: health_proto
+  headers:
+  - src/core/ext/filters/client_channel/health/health.pb.h
+  src:
+  - src/core/ext/filters/client_channel/health/health.pb.c
+  uses:
+  - nanopb
 - name: nanopb
   src:
   - third_party/nanopb/pb_common.c
@@ -1360,7 +1370,6 @@ filegroups:
   - src/cpp/common/channel_filter.h
   - src/cpp/server/dynamic_thread_pool.h
   - src/cpp/server/health/default_health_check_service.h
-  - src/cpp/server/health/health.pb.h
   - src/cpp/server/thread_pool_interface.h
   - src/cpp/thread_manager/thread_manager.h
   src:
@@ -1384,7 +1393,6 @@ filegroups:
   - src/cpp/server/create_default_thread_pool.cc
   - src/cpp/server/dynamic_thread_pool.cc
   - src/cpp/server/health/default_health_check_service.cc
-  - src/cpp/server/health/health.pb.c
   - src/cpp/server/health/health_check_service.cc
   - src/cpp/server/health/health_check_service_server_builder_option.cc
   - src/cpp/server/server_builder.cc
@@ -1403,6 +1411,7 @@ filegroups:
   - grpc_transport_inproc_headers
   - grpc++_codegen_base
   - nanopb_headers
+  - health_proto
 - name: grpc++_config_proto
   language: c++
   public_headers:
diff --git a/config.m4 b/config.m4
index c271c93ed3..cf6769796b 100644
--- a/config.m4
+++ b/config.m4
@@ -342,6 +342,7 @@ if test "$PHP_GRPC" != "no"; then
     src/core/ext/filters/client_channel/client_channel_factory.cc \
     src/core/ext/filters/client_channel/client_channel_plugin.cc \
     src/core/ext/filters/client_channel/connector.cc \
+    src/core/ext/filters/client_channel/health/health_check_client.cc \
     src/core/ext/filters/client_channel/http_connect_handshaker.cc \
     src/core/ext/filters/client_channel/http_proxy.cc \
     src/core/ext/filters/client_channel/lb_policy.cc \
@@ -358,6 +359,7 @@ if test "$PHP_GRPC" != "no"; then
     src/core/ext/filters/client_channel/subchannel_index.cc \
     src/core/ext/filters/client_channel/uri_parser.cc \
     src/core/ext/filters/deadline/deadline_filter.cc \
+    src/core/ext/filters/client_channel/health/health.pb.c \
     src/core/tsi/alts_transport_security.cc \
     src/core/tsi/fake_transport_security.cc \
     src/core/tsi/local_transport_security.cc \
@@ -670,6 +672,7 @@ if test "$PHP_GRPC" != "no"; then
   PHP_ADD_BUILD_DIR($ext_builddir/src/boringssl)
   PHP_ADD_BUILD_DIR($ext_builddir/src/core/ext/filters/census)
   PHP_ADD_BUILD_DIR($ext_builddir/src/core/ext/filters/client_channel)
+  PHP_ADD_BUILD_DIR($ext_builddir/src/core/ext/filters/client_channel/health)
   PHP_ADD_BUILD_DIR($ext_builddir/src/core/ext/filters/client_channel/lb_policy/grpclb)
   PHP_ADD_BUILD_DIR($ext_builddir/src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1)
   PHP_ADD_BUILD_DIR($ext_builddir/src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/google/protobuf)
diff --git a/config.w32 b/config.w32
index 10e28cff7c..da1279ccbc 100644
--- a/config.w32
+++ b/config.w32
@@ -317,6 +317,7 @@ if (PHP_GRPC != "no") {
     "src\\core\\ext\\filters\\client_channel\\client_channel_factory.cc " +
     "src\\core\\ext\\filters\\client_channel\\client_channel_plugin.cc " +
     "src\\core\\ext\\filters\\client_channel\\connector.cc " +
+    "src\\core\\ext\\filters\\client_channel\\health\\health_check_client.cc " +
     "src\\core\\ext\\filters\\client_channel\\http_connect_handshaker.cc " +
     "src\\core\\ext\\filters\\client_channel\\http_proxy.cc " +
     "src\\core\\ext\\filters\\client_channel\\lb_policy.cc " +
@@ -333,6 +334,7 @@ if (PHP_GRPC != "no") {
     "src\\core\\ext\\filters\\client_channel\\subchannel_index.cc " +
     "src\\core\\ext\\filters\\client_channel\\uri_parser.cc " +
     "src\\core\\ext\\filters\\deadline\\deadline_filter.cc " +
+    "src\\core\\ext\\filters\\client_channel\\health\\health.pb.c " +
     "src\\core\\tsi\\alts_transport_security.cc " +
     "src\\core\\tsi\\fake_transport_security.cc " +
     "src\\core\\tsi\\local_transport_security.cc " +
@@ -675,6 +677,7 @@ if (PHP_GRPC != "no") {
   FSO.CreateFolder(base_dir+"\\ext\\grpc\\src\\core\\ext\\filters");
   FSO.CreateFolder(base_dir+"\\ext\\grpc\\src\\core\\ext\\filters\\census");
   FSO.CreateFolder(base_dir+"\\ext\\grpc\\src\\core\\ext\\filters\\client_channel");
+  FSO.CreateFolder(base_dir+"\\ext\\grpc\\src\\core\\ext\\filters\\client_channel\\health");
   FSO.CreateFolder(base_dir+"\\ext\\grpc\\src\\core\\ext\\filters\\client_channel\\lb_policy");
   FSO.CreateFolder(base_dir+"\\ext\\grpc\\src\\core\\ext\\filters\\client_channel\\lb_policy\\grpclb");
   FSO.CreateFolder(base_dir+"\\ext\\grpc\\src\\core\\ext\\filters\\client_channel\\lb_policy\\grpclb\\proto");
diff --git a/doc/environment_variables.md b/doc/environment_variables.md
index b472f7e126..1eb850e976 100644
--- a/doc/environment_variables.md
+++ b/doc/environment_variables.md
@@ -52,6 +52,7 @@ some configuration as environment variables that can be set.
     traces epoll-fd creation/close calls for epollex polling engine
   - glb - traces the grpclb load balancer
   - handshaker - traces handshaking state
+  - health_check_client - traces health checking client code
   - http - traces state in the http2 transport engine
   - http2_stream_state - traces all http2 stream state mutations.
   - http1 - traces HTTP/1.x operations performed by gRPC
diff --git a/gRPC-C++.podspec b/gRPC-C++.podspec
index d65009cbe3..187551da87 100644
--- a/gRPC-C++.podspec
+++ b/gRPC-C++.podspec
@@ -173,7 +173,6 @@ Pod::Spec.new do |s|
                       'src/cpp/common/channel_filter.h',
                       'src/cpp/server/dynamic_thread_pool.h',
                       'src/cpp/server/health/default_health_check_service.h',
-                      'src/cpp/server/health/health.pb.h',
                       'src/cpp/server/thread_pool_interface.h',
                       'src/cpp/thread_manager/thread_manager.h',
                       'src/cpp/client/insecure_credentials.cc',
@@ -204,7 +203,6 @@ Pod::Spec.new do |s|
                       'src/cpp/server/create_default_thread_pool.cc',
                       'src/cpp/server/dynamic_thread_pool.cc',
                       'src/cpp/server/health/default_health_check_service.cc',
-                      'src/cpp/server/health/health.pb.c',
                       'src/cpp/server/health/health_check_service.cc',
                       'src/cpp/server/health/health_check_service_server_builder_option.cc',
                       'src/cpp/server/server_builder.cc',
@@ -332,6 +330,7 @@ Pod::Spec.new do |s|
                       'src/core/ext/filters/client_channel/client_channel_channelz.h',
                       'src/core/ext/filters/client_channel/client_channel_factory.h',
                       'src/core/ext/filters/client_channel/connector.h',
+                      'src/core/ext/filters/client_channel/health/health_check_client.h',
                       'src/core/ext/filters/client_channel/http_connect_handshaker.h',
                       'src/core/ext/filters/client_channel/http_proxy.h',
                       'src/core/ext/filters/client_channel/lb_policy.h',
@@ -349,6 +348,7 @@ Pod::Spec.new do |s|
                       'src/core/ext/filters/client_channel/subchannel_index.h',
                       'src/core/ext/filters/client_channel/uri_parser.h',
                       'src/core/ext/filters/deadline/deadline_filter.h',
+                      'src/core/ext/filters/client_channel/health/health.pb.h',
                       'src/core/tsi/alts_transport_security.h',
                       'src/core/tsi/fake_transport_security.h',
                       'src/core/tsi/local_transport_security.h',
@@ -523,7 +523,6 @@ Pod::Spec.new do |s|
                               'src/cpp/common/channel_filter.h',
                               'src/cpp/server/dynamic_thread_pool.h',
                               'src/cpp/server/health/default_health_check_service.h',
-                              'src/cpp/server/health/health.pb.h',
                               'src/cpp/server/thread_pool_interface.h',
                               'src/cpp/thread_manager/thread_manager.h',
                               'src/core/lib/gpr/alloc.h',
@@ -687,7 +686,8 @@ Pod::Spec.new do |s|
                               'src/core/lib/transport/transport.h',
                               'src/core/lib/transport/transport_impl.h',
                               'src/core/lib/debug/trace.h',
-                              'src/core/ext/transport/inproc/inproc_transport.h'
+                              'src/core/ext/transport/inproc/inproc_transport.h',
+                              'src/core/ext/filters/client_channel/health/health.pb.h'
   end
 
   s.subspec 'Protobuf' do |ss|
diff --git a/gRPC-Core.podspec b/gRPC-Core.podspec
index c3e0c4d8cb..bbd5d7e961 100644
--- a/gRPC-Core.podspec
+++ b/gRPC-Core.podspec
@@ -339,6 +339,7 @@ Pod::Spec.new do |s|
                       'src/core/ext/filters/client_channel/client_channel_channelz.h',
                       'src/core/ext/filters/client_channel/client_channel_factory.h',
                       'src/core/ext/filters/client_channel/connector.h',
+                      'src/core/ext/filters/client_channel/health/health_check_client.h',
                       'src/core/ext/filters/client_channel/http_connect_handshaker.h',
                       'src/core/ext/filters/client_channel/http_proxy.h',
                       'src/core/ext/filters/client_channel/lb_policy.h',
@@ -356,6 +357,7 @@ Pod::Spec.new do |s|
                       'src/core/ext/filters/client_channel/subchannel_index.h',
                       'src/core/ext/filters/client_channel/uri_parser.h',
                       'src/core/ext/filters/deadline/deadline_filter.h',
+                      'src/core/ext/filters/client_channel/health/health.pb.h',
                       'src/core/tsi/alts_transport_security.h',
                       'src/core/tsi/fake_transport_security.h',
                       'src/core/tsi/local_transport_security.h',
@@ -777,6 +779,7 @@ Pod::Spec.new do |s|
                       'src/core/ext/filters/client_channel/client_channel_factory.cc',
                       'src/core/ext/filters/client_channel/client_channel_plugin.cc',
                       'src/core/ext/filters/client_channel/connector.cc',
+                      'src/core/ext/filters/client_channel/health/health_check_client.cc',
                       'src/core/ext/filters/client_channel/http_connect_handshaker.cc',
                       'src/core/ext/filters/client_channel/http_proxy.cc',
                       'src/core/ext/filters/client_channel/lb_policy.cc',
@@ -793,6 +796,7 @@ Pod::Spec.new do |s|
                       'src/core/ext/filters/client_channel/subchannel_index.cc',
                       'src/core/ext/filters/client_channel/uri_parser.cc',
                       'src/core/ext/filters/deadline/deadline_filter.cc',
+                      'src/core/ext/filters/client_channel/health/health.pb.c',
                       'src/core/tsi/alts_transport_security.cc',
                       'src/core/tsi/fake_transport_security.cc',
                       'src/core/tsi/local_transport_security.cc',
@@ -954,6 +958,7 @@ Pod::Spec.new do |s|
                               'src/core/ext/filters/client_channel/client_channel_channelz.h',
                               'src/core/ext/filters/client_channel/client_channel_factory.h',
                               'src/core/ext/filters/client_channel/connector.h',
+                              'src/core/ext/filters/client_channel/health/health_check_client.h',
                               'src/core/ext/filters/client_channel/http_connect_handshaker.h',
                               'src/core/ext/filters/client_channel/http_proxy.h',
                               'src/core/ext/filters/client_channel/lb_policy.h',
@@ -971,6 +976,7 @@ Pod::Spec.new do |s|
                               'src/core/ext/filters/client_channel/subchannel_index.h',
                               'src/core/ext/filters/client_channel/uri_parser.h',
                               'src/core/ext/filters/deadline/deadline_filter.h',
+                              'src/core/ext/filters/client_channel/health/health.pb.h',
                               'src/core/tsi/alts_transport_security.h',
                               'src/core/tsi/fake_transport_security.h',
                               'src/core/tsi/local_transport_security.h',
@@ -1216,6 +1222,9 @@ Pod::Spec.new do |s|
                       'test/core/util/tracer_util.cc',
                       'test/core/util/trickle_endpoint.cc',
                       'test/core/util/cmdline.cc',
+                      'third_party/nanopb/pb_common.c',
+                      'third_party/nanopb/pb_decode.c',
+                      'third_party/nanopb/pb_encode.c',
                       'test/core/end2end/data/ssl_test_data.h',
                       'test/core/security/oauth2_utils.h',
                       'test/core/end2end/cq_verifier.h',
@@ -1237,6 +1246,10 @@ Pod::Spec.new do |s|
                       'test/core/util/tracer_util.h',
                       'test/core/util/trickle_endpoint.h',
                       'test/core/util/cmdline.h',
+                      'third_party/nanopb/pb.h',
+                      'third_party/nanopb/pb_common.h',
+                      'third_party/nanopb/pb_decode.h',
+                      'third_party/nanopb/pb_encode.h',
                       'test/core/end2end/end2end_tests.cc',
                       'test/core/end2end/end2end_test_utils.cc',
                       'test/core/end2end/tests/authority_not_supported.cc',
diff --git a/grpc.gemspec b/grpc.gemspec
index 8128044652..a3924d0d93 100644
--- a/grpc.gemspec
+++ b/grpc.gemspec
@@ -275,6 +275,7 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/ext/filters/client_channel/client_channel_channelz.h )
   s.files += %w( src/core/ext/filters/client_channel/client_channel_factory.h )
   s.files += %w( src/core/ext/filters/client_channel/connector.h )
+  s.files += %w( src/core/ext/filters/client_channel/health/health_check_client.h )
   s.files += %w( src/core/ext/filters/client_channel/http_connect_handshaker.h )
   s.files += %w( src/core/ext/filters/client_channel/http_proxy.h )
   s.files += %w( src/core/ext/filters/client_channel/lb_policy.h )
@@ -292,6 +293,7 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/ext/filters/client_channel/subchannel_index.h )
   s.files += %w( src/core/ext/filters/client_channel/uri_parser.h )
   s.files += %w( src/core/ext/filters/deadline/deadline_filter.h )
+  s.files += %w( src/core/ext/filters/client_channel/health/health.pb.h )
   s.files += %w( src/core/tsi/alts_transport_security.h )
   s.files += %w( src/core/tsi/fake_transport_security.h )
   s.files += %w( src/core/tsi/local_transport_security.h )
@@ -716,6 +718,7 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/ext/filters/client_channel/client_channel_factory.cc )
   s.files += %w( src/core/ext/filters/client_channel/client_channel_plugin.cc )
   s.files += %w( src/core/ext/filters/client_channel/connector.cc )
+  s.files += %w( src/core/ext/filters/client_channel/health/health_check_client.cc )
   s.files += %w( src/core/ext/filters/client_channel/http_connect_handshaker.cc )
   s.files += %w( src/core/ext/filters/client_channel/http_proxy.cc )
   s.files += %w( src/core/ext/filters/client_channel/lb_policy.cc )
@@ -732,6 +735,7 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/ext/filters/client_channel/subchannel_index.cc )
   s.files += %w( src/core/ext/filters/client_channel/uri_parser.cc )
   s.files += %w( src/core/ext/filters/deadline/deadline_filter.cc )
+  s.files += %w( src/core/ext/filters/client_channel/health/health.pb.c )
   s.files += %w( src/core/tsi/alts_transport_security.cc )
   s.files += %w( src/core/tsi/fake_transport_security.cc )
   s.files += %w( src/core/tsi/local_transport_security.cc )
diff --git a/grpc.gyp b/grpc.gyp
index e593db8267..963b8b22b1 100644
--- a/grpc.gyp
+++ b/grpc.gyp
@@ -534,6 +534,7 @@
         'src/core/ext/filters/client_channel/client_channel_factory.cc',
         'src/core/ext/filters/client_channel/client_channel_plugin.cc',
         'src/core/ext/filters/client_channel/connector.cc',
+        'src/core/ext/filters/client_channel/health/health_check_client.cc',
         'src/core/ext/filters/client_channel/http_connect_handshaker.cc',
         'src/core/ext/filters/client_channel/http_proxy.cc',
         'src/core/ext/filters/client_channel/lb_policy.cc',
@@ -550,6 +551,7 @@
         'src/core/ext/filters/client_channel/subchannel_index.cc',
         'src/core/ext/filters/client_channel/uri_parser.cc',
         'src/core/ext/filters/deadline/deadline_filter.cc',
+        'src/core/ext/filters/client_channel/health/health.pb.c',
         'src/core/tsi/alts_transport_security.cc',
         'src/core/tsi/fake_transport_security.cc',
         'src/core/tsi/local_transport_security.cc',
@@ -792,6 +794,7 @@
         'src/core/ext/filters/client_channel/client_channel_factory.cc',
         'src/core/ext/filters/client_channel/client_channel_plugin.cc',
         'src/core/ext/filters/client_channel/connector.cc',
+        'src/core/ext/filters/client_channel/health/health_check_client.cc',
         'src/core/ext/filters/client_channel/http_connect_handshaker.cc',
         'src/core/ext/filters/client_channel/http_proxy.cc',
         'src/core/ext/filters/client_channel/lb_policy.cc',
@@ -808,6 +811,10 @@
         'src/core/ext/filters/client_channel/subchannel_index.cc',
         'src/core/ext/filters/client_channel/uri_parser.cc',
         'src/core/ext/filters/deadline/deadline_filter.cc',
+        'src/core/ext/filters/client_channel/health/health.pb.c',
+        'third_party/nanopb/pb_common.c',
+        'third_party/nanopb/pb_decode.c',
+        'third_party/nanopb/pb_encode.c',
         'src/core/ext/transport/chttp2/transport/bin_decoder.cc',
         'src/core/ext/transport/chttp2/transport/bin_encoder.cc',
         'src/core/ext/transport/chttp2/transport/chttp2_plugin.cc',
@@ -1026,6 +1033,7 @@
         'src/core/ext/filters/client_channel/client_channel_factory.cc',
         'src/core/ext/filters/client_channel/client_channel_plugin.cc',
         'src/core/ext/filters/client_channel/connector.cc',
+        'src/core/ext/filters/client_channel/health/health_check_client.cc',
         'src/core/ext/filters/client_channel/http_connect_handshaker.cc',
         'src/core/ext/filters/client_channel/http_proxy.cc',
         'src/core/ext/filters/client_channel/lb_policy.cc',
@@ -1042,6 +1050,10 @@
         'src/core/ext/filters/client_channel/subchannel_index.cc',
         'src/core/ext/filters/client_channel/uri_parser.cc',
         'src/core/ext/filters/deadline/deadline_filter.cc',
+        'src/core/ext/filters/client_channel/health/health.pb.c',
+        'third_party/nanopb/pb_common.c',
+        'third_party/nanopb/pb_decode.c',
+        'third_party/nanopb/pb_encode.c',
         'src/core/ext/transport/chttp2/transport/bin_decoder.cc',
         'src/core/ext/transport/chttp2/transport/bin_encoder.cc',
         'src/core/ext/transport/chttp2/transport/chttp2_plugin.cc',
@@ -1272,6 +1284,7 @@
         'src/core/ext/filters/client_channel/client_channel_factory.cc',
         'src/core/ext/filters/client_channel/client_channel_plugin.cc',
         'src/core/ext/filters/client_channel/connector.cc',
+        'src/core/ext/filters/client_channel/health/health_check_client.cc',
         'src/core/ext/filters/client_channel/http_connect_handshaker.cc',
         'src/core/ext/filters/client_channel/http_proxy.cc',
         'src/core/ext/filters/client_channel/lb_policy.cc',
@@ -1288,6 +1301,10 @@
         'src/core/ext/filters/client_channel/subchannel_index.cc',
         'src/core/ext/filters/client_channel/uri_parser.cc',
         'src/core/ext/filters/deadline/deadline_filter.cc',
+        'src/core/ext/filters/client_channel/health/health.pb.c',
+        'third_party/nanopb/pb_common.c',
+        'third_party/nanopb/pb_decode.c',
+        'third_party/nanopb/pb_encode.c',
         'src/core/ext/transport/inproc/inproc_plugin.cc',
         'src/core/ext/transport/inproc/inproc_transport.cc',
         'src/core/ext/filters/client_channel/resolver/dns/c_ares/dns_resolver_ares.cc',
@@ -1306,9 +1323,6 @@
         'src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_channel.cc',
         'src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb_client_stats.cc',
         'src/core/ext/filters/client_channel/lb_policy/grpclb/load_balancer_api.cc',
-        'third_party/nanopb/pb_common.c',
-        'third_party/nanopb/pb_decode.c',
-        'third_party/nanopb/pb_encode.c',
         'src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/google/protobuf/duration.pb.c',
         'src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/google/protobuf/timestamp.pb.c',
         'src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c',
@@ -1390,7 +1404,6 @@
         'src/cpp/server/create_default_thread_pool.cc',
         'src/cpp/server/dynamic_thread_pool.cc',
         'src/cpp/server/health/default_health_check_service.cc',
-        'src/cpp/server/health/health.pb.c',
         'src/cpp/server/health/health_check_service.cc',
         'src/cpp/server/health/health_check_service_server_builder_option.cc',
         'src/cpp/server/server_builder.cc',
@@ -1403,6 +1416,10 @@
         'src/cpp/util/status.cc',
         'src/cpp/util/string_ref.cc',
         'src/cpp/util/time_cc.cc',
+        'src/core/ext/filters/client_channel/health/health.pb.c',
+        'third_party/nanopb/pb_common.c',
+        'third_party/nanopb/pb_decode.c',
+        'third_party/nanopb/pb_encode.c',
         'src/cpp/codegen/codegen_init.cc',
       ],
     },
@@ -1537,7 +1554,6 @@
         'src/cpp/server/create_default_thread_pool.cc',
         'src/cpp/server/dynamic_thread_pool.cc',
         'src/cpp/server/health/default_health_check_service.cc',
-        'src/cpp/server/health/health.pb.c',
         'src/cpp/server/health/health_check_service.cc',
         'src/cpp/server/health/health_check_service_server_builder_option.cc',
         'src/cpp/server/server_builder.cc',
@@ -1550,6 +1566,10 @@
         'src/cpp/util/status.cc',
         'src/cpp/util/string_ref.cc',
         'src/cpp/util/time_cc.cc',
+        'src/core/ext/filters/client_channel/health/health.pb.c',
+        'third_party/nanopb/pb_common.c',
+        'third_party/nanopb/pb_decode.c',
+        'third_party/nanopb/pb_encode.c',
         'src/cpp/codegen/codegen_init.cc',
       ],
     },
diff --git a/include/grpc/impl/codegen/grpc_types.h b/include/grpc/impl/codegen/grpc_types.h
index 3ce88a8264..17a43fab0f 100644
--- a/include/grpc/impl/codegen/grpc_types.h
+++ b/include/grpc/impl/codegen/grpc_types.h
@@ -347,6 +347,9 @@ typedef struct {
 /** If set to non zero, surfaces the user agent string to the server. User
     agent is surfaced by default. */
 #define GRPC_ARG_SURFACE_USER_AGENT "grpc.surface_user_agent"
+/** If set, inhibits health checking (which may be enabled via the
+ *  service config.) */
+#define GRPC_ARG_INHIBIT_HEALTH_CHECKING "grpc.inhibit_health_checking"
 /** \} */
 
 /** Result of a grpc call. If the caller satisfies the prerequisites of a
diff --git a/package.xml b/package.xml
index 76f72d41be..c90cee8fe9 100644
--- a/package.xml
+++ b/package.xml
@@ -280,6 +280,7 @@
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/client_channel_channelz.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/client_channel_factory.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/connector.h" role="src" />
+    <file baseinstalldir="/" name="src/core/ext/filters/client_channel/health/health_check_client.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/http_connect_handshaker.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/http_proxy.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/lb_policy.h" role="src" />
@@ -297,6 +298,7 @@
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/subchannel_index.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/uri_parser.h" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/deadline/deadline_filter.h" role="src" />
+    <file baseinstalldir="/" name="src/core/ext/filters/client_channel/health/health.pb.h" role="src" />
     <file baseinstalldir="/" name="src/core/tsi/alts_transport_security.h" role="src" />
     <file baseinstalldir="/" name="src/core/tsi/fake_transport_security.h" role="src" />
     <file baseinstalldir="/" name="src/core/tsi/local_transport_security.h" role="src" />
@@ -721,6 +723,7 @@
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/client_channel_factory.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/client_channel_plugin.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/connector.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/ext/filters/client_channel/health/health_check_client.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/http_connect_handshaker.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/http_proxy.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/lb_policy.cc" role="src" />
@@ -737,6 +740,7 @@
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/subchannel_index.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/client_channel/uri_parser.cc" role="src" />
     <file baseinstalldir="/" name="src/core/ext/filters/deadline/deadline_filter.cc" role="src" />
+    <file baseinstalldir="/" name="src/core/ext/filters/client_channel/health/health.pb.c" role="src" />
     <file baseinstalldir="/" name="src/core/tsi/alts_transport_security.cc" role="src" />
     <file baseinstalldir="/" name="src/core/tsi/fake_transport_security.cc" role="src" />
     <file baseinstalldir="/" name="src/core/tsi/local_transport_security.cc" role="src" />
diff --git a/src/core/ext/filters/client_channel/client_channel_channelz.cc b/src/core/ext/filters/client_channel/client_channel_channelz.cc
index bad1ef668c..8e5426081c 100644
--- a/src/core/ext/filters/client_channel/client_channel_channelz.cc
+++ b/src/core/ext/filters/client_channel/client_channel_channelz.cc
@@ -128,7 +128,8 @@ void SubchannelNode::PopulateConnectivityState(grpc_json* json) {
   if (subchannel_ == nullptr) {
     state = GRPC_CHANNEL_SHUTDOWN;
   } else {
-    state = grpc_subchannel_check_connectivity(subchannel_, nullptr);
+    state = grpc_subchannel_check_connectivity(
+        subchannel_, nullptr, true /* inhibit_health_checking */);
   }
   json = grpc_json_create_child(nullptr, json, "state", nullptr,
                                 GRPC_JSON_OBJECT, false);
diff --git a/src/cpp/server/health/health.pb.c b/src/core/ext/filters/client_channel/health/health.pb.c
index 5c214c7160..5499c549cc 100644
--- a/src/cpp/server/health/health.pb.c
+++ b/src/core/ext/filters/client_channel/health/health.pb.c
@@ -1,7 +1,7 @@
 /* Automatically generated nanopb constant definitions */
 /* Generated by nanopb-0.3.7-dev */
 
-#include "src/cpp/server/health/health.pb.h"
+#include "src/core/ext/filters/client_channel/health/health.pb.h"
 /* @@protoc_insertion_point(includes) */
 #if PB_PROTO_HEADER_VERSION != 30
 #error Regenerate this file with the current version of nanopb generator.
diff --git a/src/cpp/server/health/health.pb.h b/src/core/ext/filters/client_channel/health/health.pb.h
index 9d54ccd618..9d54ccd618 100644
--- a/src/cpp/server/health/health.pb.h
+++ b/src/core/ext/filters/client_channel/health/health.pb.h
diff --git a/src/core/ext/filters/client_channel/health/health_check_client.cc b/src/core/ext/filters/client_channel/health/health_check_client.cc
new file mode 100644
index 0000000000..400d99b07c
--- /dev/null
+++ b/src/core/ext/filters/client_channel/health/health_check_client.cc
@@ -0,0 +1,646 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include <grpc/support/port_platform.h>
+
+#include <stdint.h>
+
+#include "src/core/ext/filters/client_channel/health/health_check_client.h"
+
+#include "pb_decode.h"
+#include "pb_encode.h"
+#include "src/core/ext/filters/client_channel/health/health.pb.h"
+#include "src/core/lib/debug/trace.h"
+#include "src/core/lib/gprpp/mutex_lock.h"
+#include "src/core/lib/slice/slice_internal.h"
+#include "src/core/lib/transport/error_utils.h"
+#include "src/core/lib/transport/status_metadata.h"
+
+#define HEALTH_CHECK_INITIAL_CONNECT_BACKOFF_SECONDS 1
+#define HEALTH_CHECK_RECONNECT_BACKOFF_MULTIPLIER 1.6
+#define HEALTH_CHECK_RECONNECT_MAX_BACKOFF_SECONDS 120
+#define HEALTH_CHECK_RECONNECT_JITTER 0.2
+
+grpc_core::TraceFlag grpc_health_check_client_trace(false,
+                                                    "health_check_client");
+
+namespace grpc_core {
+
+//
+// HealthCheckClient
+//
+
+HealthCheckClient::HealthCheckClient(
+    const char* service_name,
+    RefCountedPtr<ConnectedSubchannel> connected_subchannel,
+    grpc_pollset_set* interested_parties,
+    grpc_core::RefCountedPtr<grpc_core::channelz::SubchannelNode> channelz_node)
+    : InternallyRefCountedWithTracing<HealthCheckClient>(
+          &grpc_health_check_client_trace),
+      service_name_(service_name),
+      connected_subchannel_(std::move(connected_subchannel)),
+      interested_parties_(interested_parties),
+      channelz_node_(std::move(channelz_node)),
+      retry_backoff_(
+          BackOff::Options()
+              .set_initial_backoff(
+                  HEALTH_CHECK_INITIAL_CONNECT_BACKOFF_SECONDS * 1000)
+              .set_multiplier(HEALTH_CHECK_RECONNECT_BACKOFF_MULTIPLIER)
+              .set_jitter(HEALTH_CHECK_RECONNECT_JITTER)
+              .set_max_backoff(HEALTH_CHECK_RECONNECT_MAX_BACKOFF_SECONDS *
+                               1000)) {
+  if (grpc_health_check_client_trace.enabled()) {
+    gpr_log(GPR_INFO, "created HealthCheckClient %p", this);
+  }
+  GRPC_CLOSURE_INIT(&retry_timer_callback_, OnRetryTimer, this,
+                    grpc_schedule_on_exec_ctx);
+  gpr_mu_init(&mu_);
+  StartCall();
+}
+
+HealthCheckClient::~HealthCheckClient() {
+  if (grpc_health_check_client_trace.enabled()) {
+    gpr_log(GPR_INFO, "destroying HealthCheckClient %p", this);
+  }
+  GRPC_ERROR_UNREF(error_);
+  gpr_mu_destroy(&mu_);
+}
+
+void HealthCheckClient::NotifyOnHealthChange(grpc_connectivity_state* state,
+                                             grpc_closure* closure) {
+  MutexLock lock(&mu_);
+  GPR_ASSERT(notify_state_ == nullptr);
+  if (*state != state_) {
+    *state = state_;
+    GRPC_CLOSURE_SCHED(closure, GRPC_ERROR_REF(error_));
+    return;
+  }
+  notify_state_ = state;
+  on_health_changed_ = closure;
+}
+
+void HealthCheckClient::SetHealthStatus(grpc_connectivity_state state,
+                                        grpc_error* error) {
+  MutexLock lock(&mu_);
+  SetHealthStatusLocked(state, error);
+}
+
+void HealthCheckClient::SetHealthStatusLocked(grpc_connectivity_state state,
+                                              grpc_error* error) {
+  if (grpc_health_check_client_trace.enabled()) {
+    gpr_log(GPR_INFO, "HealthCheckClient %p: setting state=%d error=%s", this,
+            state, grpc_error_string(error));
+  }
+  if (notify_state_ != nullptr && *notify_state_ != state) {
+    *notify_state_ = state;
+    notify_state_ = nullptr;
+    GRPC_CLOSURE_SCHED(on_health_changed_, GRPC_ERROR_REF(error));
+    on_health_changed_ = nullptr;
+  }
+  state_ = state;
+  GRPC_ERROR_UNREF(error_);
+  error_ = error;
+}
+
+void HealthCheckClient::Orphan() {
+  if (grpc_health_check_client_trace.enabled()) {
+    gpr_log(GPR_INFO, "HealthCheckClient %p: shutting down", this);
+  }
+  {
+    MutexLock lock(&mu_);
+    if (on_health_changed_ != nullptr) {
+      *notify_state_ = GRPC_CHANNEL_SHUTDOWN;
+      notify_state_ = nullptr;
+      GRPC_CLOSURE_SCHED(on_health_changed_, GRPC_ERROR_NONE);
+      on_health_changed_ = nullptr;
+    }
+    shutting_down_ = true;
+    call_state_.reset();
+    if (retry_timer_callback_pending_) {
+      grpc_timer_cancel(&retry_timer_);
+    }
+  }
+  Unref(DEBUG_LOCATION, "orphan");
+}
+
+void HealthCheckClient::StartCall() {
+  MutexLock lock(&mu_);
+  StartCallLocked();
+}
+
+void HealthCheckClient::StartCallLocked() {
+  if (shutting_down_) return;
+  GPR_ASSERT(call_state_ == nullptr);
+  SetHealthStatusLocked(GRPC_CHANNEL_CONNECTING, GRPC_ERROR_NONE);
+  call_state_ = MakeOrphanable<CallState>(Ref(), interested_parties_);
+  if (grpc_health_check_client_trace.enabled()) {
+    gpr_log(GPR_INFO, "HealthCheckClient %p: created CallState %p", this,
+            call_state_.get());
+  }
+  call_state_->StartCall();
+}
+
+void HealthCheckClient::StartRetryTimer() {
+  MutexLock lock(&mu_);
+  SetHealthStatusLocked(
+      GRPC_CHANNEL_TRANSIENT_FAILURE,
+      GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+          "health check call failed; will retry after backoff"));
+  grpc_millis next_try = retry_backoff_.NextAttemptTime();
+  if (grpc_health_check_client_trace.enabled()) {
+    gpr_log(GPR_INFO, "HealthCheckClient %p: health check call lost...", this);
+    grpc_millis timeout = next_try - ExecCtx::Get()->Now();
+    if (timeout > 0) {
+      gpr_log(GPR_INFO,
+              "HealthCheckClient %p: ... will retry in %" PRId64 "ms.", this,
+              timeout);
+    } else {
+      gpr_log(GPR_INFO, "HealthCheckClient %p: ... retrying immediately.",
+              this);
+    }
+  }
+  // Ref for callback, tracked manually.
+  Ref(DEBUG_LOCATION, "health_retry_timer").release();
+  retry_timer_callback_pending_ = true;
+  grpc_timer_init(&retry_timer_, next_try, &retry_timer_callback_);
+}
+
+void HealthCheckClient::OnRetryTimer(void* arg, grpc_error* error) {
+  HealthCheckClient* self = static_cast<HealthCheckClient*>(arg);
+  {
+    MutexLock lock(&self->mu_);
+    self->retry_timer_callback_pending_ = false;
+    if (!self->shutting_down_ && error == GRPC_ERROR_NONE &&
+        self->call_state_ == nullptr) {
+      if (grpc_health_check_client_trace.enabled()) {
+        gpr_log(GPR_INFO, "HealthCheckClient %p: restarting health check call",
+                self);
+      }
+      self->StartCallLocked();
+    }
+  }
+  self->Unref(DEBUG_LOCATION, "health_retry_timer");
+}
+
+//
+// protobuf helpers
+//
+
+namespace {
+
+void EncodeRequest(const char* service_name,
+                   ManualConstructor<SliceBufferByteStream>* send_message) {
+  grpc_health_v1_HealthCheckRequest request_struct;
+  request_struct.has_service = true;
+  snprintf(request_struct.service, sizeof(request_struct.service), "%s",
+           service_name);
+  pb_ostream_t ostream;
+  memset(&ostream, 0, sizeof(ostream));
+  pb_encode(&ostream, grpc_health_v1_HealthCheckRequest_fields,
+            &request_struct);
+  grpc_slice request_slice = GRPC_SLICE_MALLOC(ostream.bytes_written);
+  ostream = pb_ostream_from_buffer(GRPC_SLICE_START_PTR(request_slice),
+                                   GRPC_SLICE_LENGTH(request_slice));
+  GPR_ASSERT(pb_encode(&ostream, grpc_health_v1_HealthCheckRequest_fields,
+                       &request_struct) != 0);
+  grpc_slice_buffer slice_buffer;
+  grpc_slice_buffer_init(&slice_buffer);
+  grpc_slice_buffer_add(&slice_buffer, request_slice);
+  send_message->Init(&slice_buffer, 0);
+  grpc_slice_buffer_destroy_internal(&slice_buffer);
+}
+
+// Returns true if healthy.
+// If there was an error parsing the response, sets *error and returns false.
+bool DecodeResponse(grpc_slice_buffer* slice_buffer, grpc_error** error) {
+  // If message is empty, assume unhealthy.
+  if (slice_buffer->length == 0) {
+    *error =
+        GRPC_ERROR_CREATE_FROM_STATIC_STRING("health check response was empty");
+    return false;
+  }
+  // Concatenate the slices to form a single string.
+  UniquePtr<uint8_t> recv_message_deleter;
+  uint8_t* recv_message;
+  if (slice_buffer->count == 1) {
+    recv_message = GRPC_SLICE_START_PTR(slice_buffer->slices[0]);
+  } else {
+    recv_message = static_cast<uint8_t*>(gpr_malloc(slice_buffer->length));
+    recv_message_deleter.reset(recv_message);
+    size_t offset = 0;
+    for (size_t i = 0; i < slice_buffer->count; ++i) {
+      memcpy(recv_message + offset,
+             GRPC_SLICE_START_PTR(slice_buffer->slices[i]),
+             GRPC_SLICE_LENGTH(slice_buffer->slices[i]));
+      offset += GRPC_SLICE_LENGTH(slice_buffer->slices[i]);
+    }
+  }
+  // Deserialize message.
+  grpc_health_v1_HealthCheckResponse response_struct;
+  pb_istream_t istream =
+      pb_istream_from_buffer(recv_message, slice_buffer->length);
+  if (!pb_decode(&istream, grpc_health_v1_HealthCheckResponse_fields,
+                 &response_struct)) {
+    // Can't parse message; assume unhealthy.
+    *error = GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+        "cannot parse health check response");
+    return false;
+  }
+  if (!response_struct.has_status) {
+    // Field not present; assume unhealthy.
+    *error = GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+        "status field not present in health check response");
+    return false;
+  }
+  return response_struct.status ==
+         grpc_health_v1_HealthCheckResponse_ServingStatus_SERVING;
+}
+
+}  // namespace
+
+//
+// HealthCheckClient::CallState
+//
+
+HealthCheckClient::CallState::CallState(
+    RefCountedPtr<HealthCheckClient> health_check_client,
+    grpc_pollset_set* interested_parties)
+    : InternallyRefCountedWithTracing<CallState>(
+          &grpc_health_check_client_trace),
+      health_check_client_(std::move(health_check_client)),
+      pollent_(grpc_polling_entity_create_from_pollset_set(interested_parties)),
+      arena_(gpr_arena_create(health_check_client_->connected_subchannel_
+                                  ->GetInitialCallSizeEstimate(0))) {
+  memset(&call_combiner_, 0, sizeof(call_combiner_));
+  grpc_call_combiner_init(&call_combiner_);
+  memset(context_, 0, sizeof(context_));
+  gpr_atm_rel_store(&seen_response_, static_cast<gpr_atm>(0));
+}
+
+HealthCheckClient::CallState::~CallState() {
+  if (grpc_health_check_client_trace.enabled()) {
+    gpr_log(GPR_INFO, "HealthCheckClient %p: destroying CallState %p",
+            health_check_client_.get(), this);
+  }
+  if (call_ != nullptr) GRPC_SUBCHANNEL_CALL_UNREF(call_, "call_ended");
+  // Unset the call combiner cancellation closure.  This has the
+  // effect of scheduling the previously set cancellation closure, if
+  // any, so that it can release any internal references it may be
+  // holding to the call stack. Also flush the closures on exec_ctx so that
+  // filters that schedule cancel notification closures on exec_ctx do not
+  // need to take a ref of the call stack to guarantee closure liveness.
+  grpc_call_combiner_set_notify_on_cancel(&call_combiner_, nullptr);
+  grpc_core::ExecCtx::Get()->Flush();
+  grpc_call_combiner_destroy(&call_combiner_);
+  gpr_arena_destroy(arena_);
+}
+
+void HealthCheckClient::CallState::Orphan() {
+  grpc_call_combiner_cancel(&call_combiner_, GRPC_ERROR_CANCELLED);
+  Cancel();
+}
+
+void HealthCheckClient::CallState::StartCall() {
+  ConnectedSubchannel::CallArgs args = {
+      &pollent_,
+      GRPC_MDSTR_SLASH_GRPC_DOT_HEALTH_DOT_V1_DOT_HEALTH_SLASH_WATCH,
+      gpr_now(GPR_CLOCK_MONOTONIC),  // start_time
+      GRPC_MILLIS_INF_FUTURE,        // deadline
+      arena_,
+      context_,
+      &call_combiner_,
+      0,  // parent_data_size
+  };
+  grpc_error* error =
+      health_check_client_->connected_subchannel_->CreateCall(args, &call_);
+  if (error != GRPC_ERROR_NONE) {
+    gpr_log(GPR_ERROR,
+            "HealthCheckClient %p CallState %p: error creating health "
+            "checking call on subchannel (%s); will retry",
+            health_check_client_.get(), this, grpc_error_string(error));
+    GRPC_ERROR_UNREF(error);
+    // Schedule instead of running directly, since we must not be
+    // holding health_check_client_->mu_ when CallEnded() is called.
+    Ref(DEBUG_LOCATION, "call_end_closure").release();
+    GRPC_CLOSURE_SCHED(
+        GRPC_CLOSURE_INIT(&batch_.handler_private.closure, CallEndedRetry, this,
+                          grpc_schedule_on_exec_ctx),
+        GRPC_ERROR_NONE);
+    return;
+  }
+  // Initialize payload and batch.
+  memset(&batch_, 0, sizeof(batch_));
+  batch_.payload = &payload_;
+  // on_complete callback takes ref, handled manually.
+  Ref(DEBUG_LOCATION, "on_complete").release();
+  batch_.on_complete = GRPC_CLOSURE_INIT(&on_complete_, OnComplete, this,
+                                         grpc_schedule_on_exec_ctx);
+  // Add send_initial_metadata op.
+  grpc_metadata_batch_init(&send_initial_metadata_);
+  error = grpc_metadata_batch_add_head(
+      &send_initial_metadata_, &path_metadata_storage_,
+      grpc_mdelem_from_slices(
+          GRPC_MDSTR_PATH,
+          GRPC_MDSTR_SLASH_GRPC_DOT_HEALTH_DOT_V1_DOT_HEALTH_SLASH_WATCH));
+  GPR_ASSERT(error == GRPC_ERROR_NONE);
+  payload_.send_initial_metadata.send_initial_metadata =
+      &send_initial_metadata_;
+  payload_.send_initial_metadata.send_initial_metadata_flags = 0;
+  payload_.send_initial_metadata.peer_string = nullptr;
+  batch_.send_initial_metadata = true;
+  // Add send_message op.
+  EncodeRequest(health_check_client_->service_name_, &send_message_);
+  payload_.send_message.send_message.reset(send_message_.get());
+  batch_.send_message = true;
+  // Add send_trailing_metadata op.
+  grpc_metadata_batch_init(&send_trailing_metadata_);
+  payload_.send_trailing_metadata.send_trailing_metadata =
+      &send_trailing_metadata_;
+  batch_.send_trailing_metadata = true;
+  // Add recv_initial_metadata op.
+  grpc_metadata_batch_init(&recv_initial_metadata_);
+  payload_.recv_initial_metadata.recv_initial_metadata =
+      &recv_initial_metadata_;
+  payload_.recv_initial_metadata.recv_flags = nullptr;
+  payload_.recv_initial_metadata.trailing_metadata_available = nullptr;
+  payload_.recv_initial_metadata.peer_string = nullptr;
+  // recv_initial_metadata_ready callback takes ref, handled manually.
+  Ref(DEBUG_LOCATION, "recv_initial_metadata_ready").release();
+  payload_.recv_initial_metadata.recv_initial_metadata_ready =
+      GRPC_CLOSURE_INIT(&recv_initial_metadata_ready_, RecvInitialMetadataReady,
+                        this, grpc_schedule_on_exec_ctx);
+  batch_.recv_initial_metadata = true;
+  // Add recv_message op.
+  payload_.recv_message.recv_message = &recv_message_;
+  // recv_message callback takes ref, handled manually.
+  Ref(DEBUG_LOCATION, "recv_message_ready").release();
+  payload_.recv_message.recv_message_ready = GRPC_CLOSURE_INIT(
+      &recv_message_ready_, RecvMessageReady, this, grpc_schedule_on_exec_ctx);
+  batch_.recv_message = true;
+  // Start batch.
+  StartBatch(&batch_);
+  // Initialize recv_trailing_metadata batch.
+  memset(&recv_trailing_metadata_batch_, 0,
+         sizeof(recv_trailing_metadata_batch_));
+  recv_trailing_metadata_batch_.payload = &payload_;
+  // Add recv_trailing_metadata op.
+  grpc_metadata_batch_init(&recv_trailing_metadata_);
+  payload_.recv_trailing_metadata.recv_trailing_metadata =
+      &recv_trailing_metadata_;
+  payload_.recv_trailing_metadata.collect_stats = &collect_stats_;
+  // This callback signals the end of the call, so it relies on the
+  // initial ref instead of taking a new ref.  When it's invoked, the
+  // initial ref is released.
+  payload_.recv_trailing_metadata.recv_trailing_metadata_ready =
+      GRPC_CLOSURE_INIT(&recv_trailing_metadata_ready_,
+                        RecvTrailingMetadataReady, this,
+                        grpc_schedule_on_exec_ctx);
+  recv_trailing_metadata_batch_.recv_trailing_metadata = true;
+  // Start recv_trailing_metadata batch.
+  StartBatch(&recv_trailing_metadata_batch_);
+}
+
+void HealthCheckClient::CallState::StartBatchInCallCombiner(void* arg,
+                                                            grpc_error* error) {
+  grpc_transport_stream_op_batch* batch =
+      static_cast<grpc_transport_stream_op_batch*>(arg);
+  grpc_subchannel_call* call =
+      static_cast<grpc_subchannel_call*>(batch->handler_private.extra_arg);
+  grpc_subchannel_call_process_op(call, batch);
+}
+
+void HealthCheckClient::CallState::StartBatch(
+    grpc_transport_stream_op_batch* batch) {
+  batch->handler_private.extra_arg = call_;
+  GRPC_CLOSURE_INIT(&batch->handler_private.closure, StartBatchInCallCombiner,
+                    batch, grpc_schedule_on_exec_ctx);
+  GRPC_CALL_COMBINER_START(&call_combiner_, &batch->handler_private.closure,
+                           GRPC_ERROR_NONE, "start_subchannel_batch");
+}
+
+void HealthCheckClient::CallState::OnCancelComplete(void* arg,
+                                                    grpc_error* error) {
+  HealthCheckClient::CallState* self =
+      static_cast<HealthCheckClient::CallState*>(arg);
+  GRPC_CALL_COMBINER_STOP(&self->call_combiner_, "health_cancel");
+  self->Unref(DEBUG_LOCATION, "cancel");
+}
+
+void HealthCheckClient::CallState::StartCancel(void* arg, grpc_error* error) {
+  HealthCheckClient::CallState* self =
+      static_cast<HealthCheckClient::CallState*>(arg);
+  auto* batch = grpc_make_transport_stream_op(
+      GRPC_CLOSURE_CREATE(OnCancelComplete, self, grpc_schedule_on_exec_ctx));
+  batch->cancel_stream = true;
+  batch->payload->cancel_stream.cancel_error = GRPC_ERROR_CANCELLED;
+  grpc_subchannel_call_process_op(self->call_, batch);
+}
+
+void HealthCheckClient::CallState::Cancel() {
+  if (call_ != nullptr) {
+    Ref(DEBUG_LOCATION, "cancel").release();
+    GRPC_CALL_COMBINER_START(
+        &call_combiner_,
+        GRPC_CLOSURE_CREATE(StartCancel, this, grpc_schedule_on_exec_ctx),
+        GRPC_ERROR_NONE, "health_cancel");
+  }
+}
+
+void HealthCheckClient::CallState::OnComplete(void* arg, grpc_error* error) {
+  HealthCheckClient::CallState* self =
+      static_cast<HealthCheckClient::CallState*>(arg);
+  GRPC_CALL_COMBINER_STOP(&self->call_combiner_, "on_complete");
+  grpc_metadata_batch_destroy(&self->send_initial_metadata_);
+  grpc_metadata_batch_destroy(&self->send_trailing_metadata_);
+  self->Unref(DEBUG_LOCATION, "on_complete");
+}
+
+void HealthCheckClient::CallState::RecvInitialMetadataReady(void* arg,
+                                                            grpc_error* error) {
+  HealthCheckClient::CallState* self =
+      static_cast<HealthCheckClient::CallState*>(arg);
+  GRPC_CALL_COMBINER_STOP(&self->call_combiner_, "recv_initial_metadata_ready");
+  grpc_metadata_batch_destroy(&self->recv_initial_metadata_);
+  self->Unref(DEBUG_LOCATION, "recv_initial_metadata_ready");
+}
+
+void HealthCheckClient::CallState::DoneReadingRecvMessage(grpc_error* error) {
+  recv_message_.reset();
+  if (error != GRPC_ERROR_NONE) {
+    GRPC_ERROR_UNREF(error);
+    Cancel();
+    grpc_slice_buffer_destroy_internal(&recv_message_buffer_);
+    Unref(DEBUG_LOCATION, "recv_message_ready");
+    return;
+  }
+  const bool healthy = DecodeResponse(&recv_message_buffer_, &error);
+  const grpc_connectivity_state state =
+      healthy ? GRPC_CHANNEL_READY : GRPC_CHANNEL_TRANSIENT_FAILURE;
+  if (error == GRPC_ERROR_NONE && !healthy) {
+    error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("backend unhealthy");
+  }
+  health_check_client_->SetHealthStatus(state, error);
+  gpr_atm_rel_store(&seen_response_, static_cast<gpr_atm>(1));
+  grpc_slice_buffer_destroy_internal(&recv_message_buffer_);
+  // Start another recv_message batch.
+  // This re-uses the ref we're holding.
+  // Note: Can't just reuse batch_ here, since we don't know that all
+  // callbacks from the original batch have completed yet.
+  memset(&recv_message_batch_, 0, sizeof(recv_message_batch_));
+  recv_message_batch_.payload = &payload_;
+  payload_.recv_message.recv_message = &recv_message_;
+  payload_.recv_message.recv_message_ready = GRPC_CLOSURE_INIT(
+      &recv_message_ready_, RecvMessageReady, this, grpc_schedule_on_exec_ctx);
+  recv_message_batch_.recv_message = true;
+  StartBatch(&recv_message_batch_);
+}
+
+grpc_error* HealthCheckClient::CallState::PullSliceFromRecvMessage() {
+  grpc_slice slice;
+  grpc_error* error = recv_message_->Pull(&slice);
+  if (error == GRPC_ERROR_NONE) {
+    grpc_slice_buffer_add(&recv_message_buffer_, slice);
+  }
+  return error;
+}
+
+void HealthCheckClient::CallState::ContinueReadingRecvMessage() {
+  while (recv_message_->Next(SIZE_MAX, &recv_message_ready_)) {
+    grpc_error* error = PullSliceFromRecvMessage();
+    if (error != GRPC_ERROR_NONE) {
+      DoneReadingRecvMessage(error);
+      return;
+    }
+    if (recv_message_buffer_.length == recv_message_->length()) {
+      DoneReadingRecvMessage(GRPC_ERROR_NONE);
+      break;
+    }
+  }
+}
+
+void HealthCheckClient::CallState::OnByteStreamNext(void* arg,
+                                                    grpc_error* error) {
+  HealthCheckClient::CallState* self =
+      static_cast<HealthCheckClient::CallState*>(arg);
+  if (error != GRPC_ERROR_NONE) {
+    self->DoneReadingRecvMessage(GRPC_ERROR_REF(error));
+    return;
+  }
+  error = self->PullSliceFromRecvMessage();
+  if (error != GRPC_ERROR_NONE) {
+    self->DoneReadingRecvMessage(error);
+    return;
+  }
+  if (self->recv_message_buffer_.length == self->recv_message_->length()) {
+    self->DoneReadingRecvMessage(GRPC_ERROR_NONE);
+  } else {
+    self->ContinueReadingRecvMessage();
+  }
+}
+
+void HealthCheckClient::CallState::RecvMessageReady(void* arg,
+                                                    grpc_error* error) {
+  HealthCheckClient::CallState* self =
+      static_cast<HealthCheckClient::CallState*>(arg);
+  GRPC_CALL_COMBINER_STOP(&self->call_combiner_, "recv_message_ready");
+  if (self->recv_message_ == nullptr) {
+    self->Unref(DEBUG_LOCATION, "recv_message_ready");
+    return;
+  }
+  grpc_slice_buffer_init(&self->recv_message_buffer_);
+  GRPC_CLOSURE_INIT(&self->recv_message_ready_, OnByteStreamNext, self,
+                    grpc_schedule_on_exec_ctx);
+  self->ContinueReadingRecvMessage();
+  // Ref will continue to be held until we finish draining the byte stream.
+}
+
+void HealthCheckClient::CallState::RecvTrailingMetadataReady(
+    void* arg, grpc_error* error) {
+  HealthCheckClient::CallState* self =
+      static_cast<HealthCheckClient::CallState*>(arg);
+  GRPC_CALL_COMBINER_STOP(&self->call_combiner_,
+                          "recv_trailing_metadata_ready");
+  // Get call status.
+  grpc_status_code status = GRPC_STATUS_UNKNOWN;
+  if (error != GRPC_ERROR_NONE) {
+    grpc_error_get_status(error, GRPC_MILLIS_INF_FUTURE, &status,
+                          nullptr /* slice */, nullptr /* http_error */,
+                          nullptr /* error_string */);
+  } else if (self->recv_trailing_metadata_.idx.named.grpc_status != nullptr) {
+    status = grpc_get_status_code_from_metadata(
+        self->recv_trailing_metadata_.idx.named.grpc_status->md);
+  }
+  if (grpc_health_check_client_trace.enabled()) {
+    gpr_log(GPR_INFO,
+            "HealthCheckClient %p CallState %p: health watch failed with "
+            "status %d",
+            self->health_check_client_.get(), self, status);
+  }
+  // Clean up.
+  grpc_metadata_batch_destroy(&self->recv_trailing_metadata_);
+  // For status UNIMPLEMENTED, give up and assume always healthy.
+  bool retry = true;
+  if (status == GRPC_STATUS_UNIMPLEMENTED) {
+    static const char kErrorMessage[] =
+        "health checking Watch method returned UNIMPLEMENTED; "
+        "disabling health checks but assuming server is healthy";
+    gpr_log(GPR_ERROR, kErrorMessage);
+    if (self->health_check_client_->channelz_node_ != nullptr) {
+      self->health_check_client_->channelz_node_->AddTraceEvent(
+          channelz::ChannelTrace::Error,
+          grpc_slice_from_static_string(kErrorMessage));
+    }
+    self->health_check_client_->SetHealthStatus(GRPC_CHANNEL_READY,
+                                                GRPC_ERROR_NONE);
+    retry = false;
+  }
+  self->CallEnded(retry);
+}
+
+void HealthCheckClient::CallState::CallEndedRetry(void* arg,
+                                                  grpc_error* error) {
+  HealthCheckClient::CallState* self =
+      static_cast<HealthCheckClient::CallState*>(arg);
+  self->CallEnded(true /* retry */);
+  self->Unref(DEBUG_LOCATION, "call_end_closure");
+}
+
+void HealthCheckClient::CallState::CallEnded(bool retry) {
+  // If this CallState is still in use, this call ended because of a failure,
+  // so we need to stop using it and optionally create a new one.
+  // Otherwise, we have deliberately ended this call, and no further action
+  // is required.
+  if (this == health_check_client_->call_state_.get()) {
+    health_check_client_->call_state_.reset();
+    if (retry) {
+      GPR_ASSERT(!health_check_client_->shutting_down_);
+      if (static_cast<bool>(gpr_atm_acq_load(&seen_response_))) {
+        // If the call fails after we've gotten a successful response, reset
+        // the backoff and restart the call immediately.
+        health_check_client_->retry_backoff_.Reset();
+        health_check_client_->StartCall();
+      } else {
+        // If the call failed without receiving any messages, retry later.
+        health_check_client_->StartRetryTimer();
+      }
+    }
+  }
+  Unref(DEBUG_LOCATION, "call_ended");
+}
+
+}  // namespace grpc_core
diff --git a/src/core/ext/filters/client_channel/health/health_check_client.h b/src/core/ext/filters/client_channel/health/health_check_client.h
new file mode 100644
index 0000000000..7f77348f18
--- /dev/null
+++ b/src/core/ext/filters/client_channel/health/health_check_client.h
@@ -0,0 +1,173 @@
+/*
+ *
+ * Copyright 2018 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#ifndef GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_HEALTH_HEALTH_CHECK_CLIENT_H
+#define GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_HEALTH_HEALTH_CHECK_CLIENT_H
+
+#include <grpc/support/port_platform.h>
+
+#include <grpc/grpc.h>
+#include <grpc/support/atm.h>
+#include <grpc/support/sync.h>
+
+#include "src/core/ext/filters/client_channel/client_channel_channelz.h"
+#include "src/core/ext/filters/client_channel/subchannel.h"
+#include "src/core/lib/backoff/backoff.h"
+#include "src/core/lib/gpr/arena.h"
+#include "src/core/lib/gprpp/orphanable.h"
+#include "src/core/lib/gprpp/ref_counted_ptr.h"
+#include "src/core/lib/iomgr/call_combiner.h"
+#include "src/core/lib/iomgr/closure.h"
+#include "src/core/lib/iomgr/polling_entity.h"
+#include "src/core/lib/iomgr/timer.h"
+#include "src/core/lib/transport/byte_stream.h"
+#include "src/core/lib/transport/metadata_batch.h"
+#include "src/core/lib/transport/transport.h"
+
+namespace grpc_core {
+
+class HealthCheckClient
+    : public InternallyRefCountedWithTracing<HealthCheckClient> {
+ public:
+  HealthCheckClient(const char* service_name,
+                    RefCountedPtr<ConnectedSubchannel> connected_subchannel,
+                    grpc_pollset_set* interested_parties,
+                    RefCountedPtr<channelz::SubchannelNode> channelz_node);
+
+  ~HealthCheckClient();
+
+  // When the health state changes from *state, sets *state to the new
+  // value and schedules closure.
+  // Only one closure can be outstanding at a time.
+  void NotifyOnHealthChange(grpc_connectivity_state* state,
+                            grpc_closure* closure);
+
+  void Orphan() override;
+
+ private:
+  // Contains a call to the backend and all the data related to the call.
+  class CallState : public InternallyRefCountedWithTracing<CallState> {
+   public:
+    CallState(RefCountedPtr<HealthCheckClient> health_check_client,
+              grpc_pollset_set* interested_parties_);
+    ~CallState();
+
+    void Orphan() override;
+
+    void StartCall();
+
+   private:
+    void Cancel();
+
+    void StartBatch(grpc_transport_stream_op_batch* batch);
+    static void StartBatchInCallCombiner(void* arg, grpc_error* error);
+
+    static void CallEndedRetry(void* arg, grpc_error* error);
+    void CallEnded(bool retry);
+
+    static void OnComplete(void* arg, grpc_error* error);
+    static void RecvInitialMetadataReady(void* arg, grpc_error* error);
+    static void RecvMessageReady(void* arg, grpc_error* error);
+    static void RecvTrailingMetadataReady(void* arg, grpc_error* error);
+    static void StartCancel(void* arg, grpc_error* error);
+    static void OnCancelComplete(void* arg, grpc_error* error);
+
+    static void OnByteStreamNext(void* arg, grpc_error* error);
+    void ContinueReadingRecvMessage();
+    grpc_error* PullSliceFromRecvMessage();
+    void DoneReadingRecvMessage(grpc_error* error);
+
+    RefCountedPtr<HealthCheckClient> health_check_client_;
+    grpc_polling_entity pollent_;
+
+    gpr_arena* arena_;
+    grpc_call_combiner call_combiner_;
+    grpc_call_context_element context_[GRPC_CONTEXT_COUNT];
+
+    // The streaming call to the backend. Always non-NULL.
+    grpc_subchannel_call* call_;
+
+    grpc_transport_stream_op_batch_payload payload_;
+    grpc_transport_stream_op_batch batch_;
+    grpc_transport_stream_op_batch recv_message_batch_;
+    grpc_transport_stream_op_batch recv_trailing_metadata_batch_;
+
+    grpc_closure on_complete_;
+
+    // send_initial_metadata
+    grpc_metadata_batch send_initial_metadata_;
+    grpc_linked_mdelem path_metadata_storage_;
+
+    // send_message
+    ManualConstructor<SliceBufferByteStream> send_message_;
+
+    // send_trailing_metadata
+    grpc_metadata_batch send_trailing_metadata_;
+
+    // recv_initial_metadata
+    grpc_metadata_batch recv_initial_metadata_;
+    grpc_closure recv_initial_metadata_ready_;
+
+    // recv_message
+    OrphanablePtr<ByteStream> recv_message_;
+    grpc_closure recv_message_ready_;
+    grpc_slice_buffer recv_message_buffer_;
+    gpr_atm seen_response_;
+
+    // recv_trailing_metadata
+    grpc_metadata_batch recv_trailing_metadata_;
+    grpc_transport_stream_stats collect_stats_;
+    grpc_closure recv_trailing_metadata_ready_;
+  };
+
+  void StartCall();
+  void StartCallLocked();  // Requires holding mu_.
+
+  void StartRetryTimer();
+  static void OnRetryTimer(void* arg, grpc_error* error);
+
+  void SetHealthStatus(grpc_connectivity_state state, grpc_error* error);
+  void SetHealthStatusLocked(grpc_connectivity_state state,
+                             grpc_error* error);  // Requires holding mu_.
+
+  const char* service_name_;  // Do not own.
+  RefCountedPtr<ConnectedSubchannel> connected_subchannel_;
+  grpc_pollset_set* interested_parties_;  // Do not own.
+  RefCountedPtr<channelz::SubchannelNode> channelz_node_;
+
+  gpr_mu mu_;
+  grpc_connectivity_state state_ = GRPC_CHANNEL_CONNECTING;
+  grpc_error* error_ = GRPC_ERROR_NONE;
+  grpc_connectivity_state* notify_state_ = nullptr;
+  grpc_closure* on_health_changed_ = nullptr;
+  bool shutting_down_ = false;
+
+  // The data associated with the current health check call.  It holds a ref
+  // to this HealthCheckClient object.
+  OrphanablePtr<CallState> call_state_;
+
+  // Call retry state.
+  BackOff retry_backoff_;
+  grpc_timer retry_timer_;
+  grpc_closure retry_timer_callback_;
+  bool retry_timer_callback_pending_ = false;
+};
+
+}  // namespace grpc_core
+
+#endif /* GRPC_CORE_EXT_FILTERS_CLIENT_CHANNEL_HEALTH_HEALTH_CHECK_CLIENT_H */
diff --git a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc
index 5511df7a27..17e0d26875 100644
--- a/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc
+++ b/src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.cc
@@ -1699,7 +1699,7 @@ grpc_channel_args* GrpcLb::CreateRoundRobinPolicyArgsLocked() {
   // Replace the LB addresses in the channel args that we pass down to
   // the subchannel.
   static const char* keys_to_remove[] = {GRPC_ARG_LB_ADDRESSES};
-  const grpc_arg args_to_add[] = {
+  grpc_arg args_to_add[3] = {
       grpc_lb_addresses_create_channel_arg(addresses),
       // A channel arg indicating if the target is a backend inferred from a
       // grpclb load balancer.
@@ -1708,9 +1708,15 @@ grpc_channel_args* GrpcLb::CreateRoundRobinPolicyArgsLocked() {
               GRPC_ARG_ADDRESS_IS_BACKEND_FROM_GRPCLB_LOAD_BALANCER),
           is_backend_from_grpclb_load_balancer),
   };
+  size_t num_args_to_add = 2;
+  if (is_backend_from_grpclb_load_balancer) {
+    args_to_add[2] = grpc_channel_arg_integer_create(
+        const_cast<char*>(GRPC_ARG_INHIBIT_HEALTH_CHECKING), 1);
+    ++num_args_to_add;
+  }
   grpc_channel_args* args = grpc_channel_args_copy_and_add_and_remove(
       args_, keys_to_remove, GPR_ARRAY_SIZE(keys_to_remove), args_to_add,
-      GPR_ARRAY_SIZE(args_to_add));
+      num_args_to_add);
   grpc_lb_addresses_destroy(addresses);
   return args;
 }
diff --git a/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc b/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc
index f4dca146f7..eb494486b9 100644
--- a/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc
+++ b/src/core/ext/filters/client_channel/lb_policy/pick_first/pick_first.cc
@@ -359,9 +359,14 @@ void PickFirst::UpdateLocked(const grpc_channel_args& args) {
             "Pick First %p received update with %" PRIuPTR " addresses", this,
             addresses->num_addresses);
   }
+  grpc_arg new_arg = grpc_channel_arg_integer_create(
+      const_cast<char*>(GRPC_ARG_INHIBIT_HEALTH_CHECKING), 1);
+  grpc_channel_args* new_args =
+      grpc_channel_args_copy_and_add(&args, &new_arg, 1);
   auto subchannel_list = MakeOrphanable<PickFirstSubchannelList>(
       this, &grpc_lb_pick_first_trace, addresses, combiner(),
-      client_channel_factory(), args);
+      client_channel_factory(), *new_args);
+  grpc_channel_args_destroy(new_args);
   if (subchannel_list->num_subchannels() == 0) {
     // Empty update or no valid subchannels. Unsubscribe from all current
     // subchannels and put the channel in TRANSIENT_FAILURE.
diff --git a/src/core/ext/filters/client_channel/lb_policy/subchannel_list.h b/src/core/ext/filters/client_channel/lb_policy/subchannel_list.h
index e0e0e1e638..4ec9e935ed 100644
--- a/src/core/ext/filters/client_channel/lb_policy/subchannel_list.h
+++ b/src/core/ext/filters/client_channel/lb_policy/subchannel_list.h
@@ -102,8 +102,8 @@ class SubchannelData {
   // ProcessConnectivityChangeLocked()).
   grpc_connectivity_state CheckConnectivityStateLocked(grpc_error** error) {
     GPR_ASSERT(!connectivity_notification_pending_);
-    pending_connectivity_state_unsafe_ =
-        grpc_subchannel_check_connectivity(subchannel(), error);
+    pending_connectivity_state_unsafe_ = grpc_subchannel_check_connectivity(
+        subchannel(), error, subchannel_list_->inhibit_health_checking());
     UpdateConnectedSubchannelLocked();
     return pending_connectivity_state_unsafe_;
   }
@@ -216,6 +216,7 @@ class SubchannelList
   // Accessors.
   LoadBalancingPolicy* policy() const { return policy_; }
   TraceFlag* tracer() const { return tracer_; }
+  bool inhibit_health_checking() const { return inhibit_health_checking_; }
 
   // Resets connection backoff of all subchannels.
   // TODO(roth): We will probably need to rethink this as part of moving
@@ -254,6 +255,8 @@ class SubchannelList
 
   TraceFlag* tracer_;
 
+  bool inhibit_health_checking_;
+
   grpc_combiner* combiner_;
 
   // The list of subchannels.
@@ -340,7 +343,8 @@ void SubchannelData<SubchannelListType,
   subchannel_list()->Ref(DEBUG_LOCATION, "connectivity_watch").release();
   grpc_subchannel_notify_on_state_change(
       subchannel_, subchannel_list_->policy()->interested_parties(),
-      &pending_connectivity_state_unsafe_, &connectivity_changed_closure_);
+      &pending_connectivity_state_unsafe_, &connectivity_changed_closure_,
+      subchannel_list_->inhibit_health_checking());
 }
 
 template <typename SubchannelListType, typename SubchannelDataType>
@@ -359,7 +363,8 @@ void SubchannelData<SubchannelListType,
   GPR_ASSERT(connectivity_notification_pending_);
   grpc_subchannel_notify_on_state_change(
       subchannel_, subchannel_list_->policy()->interested_parties(),
-      &pending_connectivity_state_unsafe_, &connectivity_changed_closure_);
+      &pending_connectivity_state_unsafe_, &connectivity_changed_closure_,
+      subchannel_list_->inhibit_health_checking());
 }
 
 template <typename SubchannelListType, typename SubchannelDataType>
@@ -390,8 +395,9 @@ void SubchannelData<SubchannelListType, SubchannelDataType>::
             subchannel_, reason);
   }
   GPR_ASSERT(connectivity_notification_pending_);
-  grpc_subchannel_notify_on_state_change(subchannel_, nullptr, nullptr,
-                                         &connectivity_changed_closure_);
+  grpc_subchannel_notify_on_state_change(
+      subchannel_, nullptr, nullptr, &connectivity_changed_closure_,
+      subchannel_list_->inhibit_health_checking());
 }
 
 template <typename SubchannelListType, typename SubchannelDataType>
@@ -499,8 +505,13 @@ SubchannelList<SubchannelListType, SubchannelDataType>::SubchannelList(
   subchannels_.reserve(addresses->num_addresses);
   // We need to remove the LB addresses in order to be able to compare the
   // subchannel keys of subchannels from a different batch of addresses.
+  // We also remove the inhibit-health-checking arg, since we are
+  // handling that here.
+  inhibit_health_checking_ = grpc_channel_arg_get_bool(
+      grpc_channel_args_find(&args, GRPC_ARG_INHIBIT_HEALTH_CHECKING), false);
   static const char* keys_to_remove[] = {GRPC_ARG_SUBCHANNEL_ADDRESS,
-                                         GRPC_ARG_LB_ADDRESSES};
+                                         GRPC_ARG_LB_ADDRESSES,
+                                         GRPC_ARG_INHIBIT_HEALTH_CHECKING};
   // Create a subchannel for each address.
   grpc_subchannel_args sc_args;
   for (size_t i = 0; i < addresses->num_addresses; i++) {
diff --git a/src/core/ext/filters/client_channel/subchannel.cc b/src/core/ext/filters/client_channel/subchannel.cc
index a0a40eb2b3..e4c6efe862 100644
--- a/src/core/ext/filters/client_channel/subchannel.cc
+++ b/src/core/ext/filters/client_channel/subchannel.cc
@@ -30,6 +30,7 @@
 #include <grpc/support/string_util.h>
 
 #include "src/core/ext/filters/client_channel/client_channel.h"
+#include "src/core/ext/filters/client_channel/health/health_check_client.h"
 #include "src/core/ext/filters/client_channel/parse_address.h"
 #include "src/core/ext/filters/client_channel/proxy_mapper_registry.h"
 #include "src/core/ext/filters/client_channel/subchannel_index.h"
@@ -41,6 +42,7 @@
 #include "src/core/lib/gpr/alloc.h"
 #include "src/core/lib/gprpp/debug_location.h"
 #include "src/core/lib/gprpp/manual_constructor.h"
+#include "src/core/lib/gprpp/mutex_lock.h"
 #include "src/core/lib/gprpp/ref_counted_ptr.h"
 #include "src/core/lib/iomgr/sockaddr_utils.h"
 #include "src/core/lib/iomgr/timer.h"
@@ -50,6 +52,7 @@
 #include "src/core/lib/surface/channel_init.h"
 #include "src/core/lib/transport/connectivity_state.h"
 #include "src/core/lib/transport/error_utils.h"
+#include "src/core/lib/transport/service_config.h"
 #include "src/core/lib/transport/status_metadata.h"
 
 #define INTERNAL_REF_BITS 16
@@ -66,6 +69,10 @@ struct state_watcher {
   grpc_closure closure;
   grpc_subchannel* subchannel;
   grpc_connectivity_state connectivity_state;
+  grpc_connectivity_state last_connectivity_state;
+  grpc_core::OrphanablePtr<grpc_core::HealthCheckClient> health_check_client;
+  grpc_closure health_check_closure;
+  grpc_connectivity_state health_state;
 };
 }  // namespace
 
@@ -78,6 +85,12 @@ typedef struct external_state_watcher {
   struct external_state_watcher* prev;
 } external_state_watcher;
 
+namespace grpc_core {
+
+class ConnectedSubchannelStateWatcher;
+
+}  // namespace grpc_core
+
 struct grpc_subchannel {
   grpc_connector* connector;
 
@@ -109,19 +122,24 @@ struct grpc_subchannel {
       being setup */
   grpc_pollset_set* pollset_set;
 
+  grpc_core::UniquePtr<char> health_check_service_name;
+
   /** mutex protecting remaining elements */
   gpr_mu mu;
 
-  /** active connection, or null; of type grpc_core::ConnectedSubchannel
-   */
+  /** active connection, or null */
   grpc_core::RefCountedPtr<grpc_core::ConnectedSubchannel> connected_subchannel;
+  grpc_core::OrphanablePtr<grpc_core::ConnectedSubchannelStateWatcher>
+      connected_subchannel_watcher;
 
   /** have we seen a disconnection? */
   bool disconnected;
   /** are we connecting */
   bool connecting;
+
   /** connectivity state tracking */
   grpc_connectivity_state_tracker state_tracker;
+  grpc_connectivity_state_tracker state_and_health_tracker;
 
   external_state_watcher root_external_state_watcher;
 
@@ -153,6 +171,171 @@ struct grpc_subchannel_call {
   grpc_millis deadline;
 };
 
+static void maybe_start_connecting_locked(grpc_subchannel* c);
+
+static const char* subchannel_connectivity_state_change_string(
+    grpc_connectivity_state state) {
+  switch (state) {
+    case GRPC_CHANNEL_IDLE:
+      return "Subchannel state change to IDLE";
+    case GRPC_CHANNEL_CONNECTING:
+      return "Subchannel state change to CONNECTING";
+    case GRPC_CHANNEL_READY:
+      return "Subchannel state change to READY";
+    case GRPC_CHANNEL_TRANSIENT_FAILURE:
+      return "Subchannel state change to TRANSIENT_FAILURE";
+    case GRPC_CHANNEL_SHUTDOWN:
+      return "Subchannel state change to SHUTDOWN";
+  }
+  GPR_UNREACHABLE_CODE(return "UNKNOWN");
+}
+
+static void set_subchannel_connectivity_state_locked(
+    grpc_subchannel* c, grpc_connectivity_state state, grpc_error* error,
+    const char* reason) {
+  if (c->channelz_subchannel != nullptr) {
+    c->channelz_subchannel->AddTraceEvent(
+        grpc_core::channelz::ChannelTrace::Severity::Info,
+        grpc_slice_from_static_string(
+            subchannel_connectivity_state_change_string(state)));
+  }
+  grpc_connectivity_state_set(&c->state_tracker, state, error, reason);
+}
+
+namespace grpc_core {
+
+class ConnectedSubchannelStateWatcher
+    : public InternallyRefCounted<ConnectedSubchannelStateWatcher> {
+ public:
+  // Must be instantiated while holding c->mu.
+  explicit ConnectedSubchannelStateWatcher(grpc_subchannel* c)
+      : subchannel_(c) {
+    // Steal subchannel ref for connecting.
+    GRPC_SUBCHANNEL_WEAK_REF(subchannel_, "state_watcher");
+    GRPC_SUBCHANNEL_WEAK_UNREF(subchannel_, "connecting");
+    // Start watching for connectivity state changes.
+    // Callback uses initial ref to this.
+    GRPC_CLOSURE_INIT(&on_connectivity_changed_, OnConnectivityChanged, this,
+                      grpc_schedule_on_exec_ctx);
+    c->connected_subchannel->NotifyOnStateChange(c->pollset_set,
+                                                 &pending_connectivity_state_,
+                                                 &on_connectivity_changed_);
+    // Start health check if needed.
+    grpc_connectivity_state health_state = GRPC_CHANNEL_READY;
+    if (c->health_check_service_name != nullptr) {
+      health_check_client_ = grpc_core::MakeOrphanable<HealthCheckClient>(
+          c->health_check_service_name.get(), c->connected_subchannel,
+          c->pollset_set, c->channelz_subchannel);
+      GRPC_CLOSURE_INIT(&on_health_changed_, OnHealthChanged, this,
+                        grpc_schedule_on_exec_ctx);
+      Ref().release();  // Ref for health callback tracked manually.
+      health_check_client_->NotifyOnHealthChange(&health_state_,
+                                                 &on_health_changed_);
+      health_state = GRPC_CHANNEL_CONNECTING;
+    }
+    // Report initial state.
+    set_subchannel_connectivity_state_locked(
+        c, GRPC_CHANNEL_READY, GRPC_ERROR_NONE, "subchannel_connected");
+    grpc_connectivity_state_set(&c->state_and_health_tracker, health_state,
+                                GRPC_ERROR_NONE, "subchannel_connected");
+  }
+
+  ~ConnectedSubchannelStateWatcher() {
+    GRPC_SUBCHANNEL_WEAK_UNREF(subchannel_, "state_watcher");
+  }
+
+  void Orphan() override { health_check_client_.reset(); }
+
+ private:
+  static void OnConnectivityChanged(void* arg, grpc_error* error) {
+    auto* self = static_cast<ConnectedSubchannelStateWatcher*>(arg);
+    grpc_subchannel* c = self->subchannel_;
+    {
+      MutexLock lock(&c->mu);
+      switch (self->pending_connectivity_state_) {
+        case GRPC_CHANNEL_TRANSIENT_FAILURE:
+        case GRPC_CHANNEL_SHUTDOWN: {
+          if (!c->disconnected && c->connected_subchannel != nullptr) {
+            if (grpc_trace_stream_refcount.enabled()) {
+              gpr_log(GPR_INFO,
+                      "Connected subchannel %p of subchannel %p has gone into "
+                      "%s. Attempting to reconnect.",
+                      c->connected_subchannel.get(), c,
+                      grpc_connectivity_state_name(
+                          self->pending_connectivity_state_));
+            }
+            c->connected_subchannel.reset();
+            c->connected_subchannel_watcher.reset();
+            self->last_connectivity_state_ = GRPC_CHANNEL_TRANSIENT_FAILURE;
+            set_subchannel_connectivity_state_locked(
+                c, GRPC_CHANNEL_TRANSIENT_FAILURE, GRPC_ERROR_REF(error),
+                "reflect_child");
+            grpc_connectivity_state_set(&c->state_and_health_tracker,
+                                        GRPC_CHANNEL_TRANSIENT_FAILURE,
+                                        GRPC_ERROR_REF(error), "reflect_child");
+            c->backoff_begun = false;
+            c->backoff->Reset();
+            maybe_start_connecting_locked(c);
+          } else {
+            self->last_connectivity_state_ = GRPC_CHANNEL_SHUTDOWN;
+          }
+          self->health_check_client_.reset();
+          break;
+        }
+        default: {
+          // In principle, this should never happen.  We should not get
+          // a callback for READY, because that was the state we started
+          // this watch from.  And a connected subchannel should never go
+          // from READY to CONNECTING or IDLE.
+          self->last_connectivity_state_ = self->pending_connectivity_state_;
+          set_subchannel_connectivity_state_locked(
+              c, self->pending_connectivity_state_, GRPC_ERROR_REF(error),
+              "reflect_child");
+          if (self->pending_connectivity_state_ != GRPC_CHANNEL_READY) {
+            grpc_connectivity_state_set(&c->state_and_health_tracker,
+                                        self->pending_connectivity_state_,
+                                        GRPC_ERROR_REF(error), "reflect_child");
+          }
+          c->connected_subchannel->NotifyOnStateChange(
+              nullptr, &self->pending_connectivity_state_,
+              &self->on_connectivity_changed_);
+          self = nullptr;  // So we don't unref below.
+        }
+      }
+    }
+    // Don't unref until we've released the lock, because this might
+    // cause the subchannel (which contains the lock) to be destroyed.
+    if (self != nullptr) self->Unref();
+  }
+
+  static void OnHealthChanged(void* arg, grpc_error* error) {
+    auto* self = static_cast<ConnectedSubchannelStateWatcher*>(arg);
+    if (self->health_state_ == GRPC_CHANNEL_SHUTDOWN) {
+      self->Unref();
+      return;
+    }
+    grpc_subchannel* c = self->subchannel_;
+    MutexLock lock(&c->mu);
+    if (self->last_connectivity_state_ == GRPC_CHANNEL_READY) {
+      grpc_connectivity_state_set(&c->state_and_health_tracker,
+                                  self->health_state_, GRPC_ERROR_REF(error),
+                                  "health_changed");
+    }
+    self->health_check_client_->NotifyOnHealthChange(&self->health_state_,
+                                                     &self->on_health_changed_);
+  }
+
+  grpc_subchannel* subchannel_;
+  grpc_closure on_connectivity_changed_;
+  grpc_connectivity_state pending_connectivity_state_ = GRPC_CHANNEL_READY;
+  grpc_connectivity_state last_connectivity_state_ = GRPC_CHANNEL_READY;
+  grpc_core::OrphanablePtr<grpc_core::HealthCheckClient> health_check_client_;
+  grpc_closure on_health_changed_;
+  grpc_connectivity_state health_state_ = GRPC_CHANNEL_CONNECTING;
+};
+
+}  // namespace grpc_core
+
 #define SUBCHANNEL_CALL_TO_CALL_STACK(call)                          \
   (grpc_call_stack*)((char*)(call) + GPR_ROUND_UP_TO_ALIGNMENT_SIZE( \
                                          sizeof(grpc_subchannel_call)))
@@ -198,8 +381,10 @@ static void subchannel_destroy(void* arg, grpc_error* error) {
     c->channelz_subchannel.reset();
   }
   gpr_free((void*)c->filters);
+  c->health_check_service_name.reset();
   grpc_channel_args_destroy(c->args);
   grpc_connectivity_state_destroy(&c->state_tracker);
+  grpc_connectivity_state_destroy(&c->state_and_health_tracker);
   grpc_connector_unref(c->connector);
   grpc_pollset_set_destroy(c->pollset_set);
   grpc_subchannel_key_destroy(c->key);
@@ -262,6 +447,7 @@ static void disconnect(grpc_subchannel* c) {
   grpc_connector_shutdown(c->connector, GRPC_ERROR_CREATE_FROM_STATIC_STRING(
                                             "Subchannel disconnected"));
   c->connected_subchannel.reset();
+  c->connected_subchannel_watcher.reset();
   gpr_mu_unlock(&c->mu);
 }
 
@@ -337,6 +523,31 @@ static void parse_args_for_backoff_values(
       .set_max_backoff(max_backoff_ms);
 }
 
+namespace grpc_core {
+namespace {
+
+struct HealthCheckParams {
+  UniquePtr<char> service_name;
+
+  static void Parse(const grpc_json* field, HealthCheckParams* params) {
+    if (strcmp(field->key, "healthCheckConfig") == 0) {
+      if (field->type != GRPC_JSON_OBJECT) return;
+      for (grpc_json* sub_field = field->child; sub_field != nullptr;
+           sub_field = sub_field->next) {
+        if (sub_field->key == nullptr) return;
+        if (strcmp(sub_field->key, "serviceName") == 0) {
+          if (params->service_name != nullptr) return;  // Duplicate.
+          if (sub_field->type != GRPC_JSON_STRING) return;
+          params->service_name.reset(gpr_strdup(sub_field->value));
+        }
+      }
+    }
+  }
+};
+
+}  // namespace
+}  // namespace grpc_core
+
 grpc_subchannel* grpc_subchannel_create(grpc_connector* connector,
                                         const grpc_subchannel_args* args) {
   grpc_subchannel_key* key = grpc_subchannel_key_create(args);
@@ -387,12 +598,28 @@ grpc_subchannel* grpc_subchannel_create(grpc_connector* connector,
                     grpc_schedule_on_exec_ctx);
   grpc_connectivity_state_init(&c->state_tracker, GRPC_CHANNEL_IDLE,
                                "subchannel");
+  grpc_connectivity_state_init(&c->state_and_health_tracker, GRPC_CHANNEL_IDLE,
+                               "subchannel");
   grpc_core::BackOff::Options backoff_options;
   parse_args_for_backoff_values(args->args, &backoff_options,
                                 &c->min_connect_timeout_ms);
   c->backoff.Init(backoff_options);
   gpr_mu_init(&c->mu);
 
+  // Check whether we should enable health checking.
+  const char* service_config_json = grpc_channel_arg_get_string(
+      grpc_channel_args_find(c->args, GRPC_ARG_SERVICE_CONFIG));
+  if (service_config_json != nullptr) {
+    grpc_core::UniquePtr<grpc_core::ServiceConfig> service_config =
+        grpc_core::ServiceConfig::Create(service_config_json);
+    if (service_config != nullptr) {
+      grpc_core::HealthCheckParams params;
+      service_config->ParseGlobalParams(grpc_core::HealthCheckParams::Parse,
+                                        &params);
+      c->health_check_service_name = std::move(params.service_name);
+    }
+  }
+
   const grpc_arg* arg =
       grpc_channel_args_find(c->args, GRPC_ARG_ENABLE_CHANNELZ);
   bool channelz_enabled =
@@ -428,35 +655,6 @@ intptr_t grpc_subchannel_get_child_socket_uuid(grpc_subchannel* subchannel) {
   }
 }
 
-static const char* subchannel_connectivity_state_change_string(
-    grpc_connectivity_state state) {
-  switch (state) {
-    case GRPC_CHANNEL_IDLE:
-      return "Subchannel state change to IDLE";
-    case GRPC_CHANNEL_CONNECTING:
-      return "Subchannel state change to CONNECTING";
-    case GRPC_CHANNEL_READY:
-      return "Subchannel state change to READY";
-    case GRPC_CHANNEL_TRANSIENT_FAILURE:
-      return "Subchannel state change to TRANSIENT_FAILURE";
-    case GRPC_CHANNEL_SHUTDOWN:
-      return "Subchannel state change to SHUTDOWN";
-  }
-  GPR_UNREACHABLE_CODE(return "UNKNOWN");
-}
-
-static void set_subchannel_connectivity_state_locked(
-    grpc_subchannel* c, grpc_connectivity_state state, grpc_error* error,
-    const char* reason) {
-  if (c->channelz_subchannel != nullptr) {
-    c->channelz_subchannel->AddTraceEvent(
-        grpc_core::channelz::ChannelTrace::Severity::Info,
-        grpc_slice_from_static_string(
-            subchannel_connectivity_state_change_string(state)));
-  }
-  grpc_connectivity_state_set(&c->state_tracker, state, error, reason);
-}
-
 static void continue_connect_locked(grpc_subchannel* c) {
   grpc_connect_in_args args;
   args.interested_parties = c->pollset_set;
@@ -467,15 +665,19 @@ static void continue_connect_locked(grpc_subchannel* c) {
   args.channel_args = c->args;
   set_subchannel_connectivity_state_locked(c, GRPC_CHANNEL_CONNECTING,
                                            GRPC_ERROR_NONE, "connecting");
+  grpc_connectivity_state_set(&c->state_and_health_tracker,
+                              GRPC_CHANNEL_CONNECTING, GRPC_ERROR_NONE,
+                              "connecting");
   grpc_connector_connect(c->connector, &args, &c->connecting_result,
                          &c->on_connected);
 }
 
-grpc_connectivity_state grpc_subchannel_check_connectivity(grpc_subchannel* c,
-                                                           grpc_error** error) {
-  grpc_connectivity_state state;
+grpc_connectivity_state grpc_subchannel_check_connectivity(
+    grpc_subchannel* c, grpc_error** error, bool inhibit_health_checks) {
   gpr_mu_lock(&c->mu);
-  state = grpc_connectivity_state_get(&c->state_tracker, error);
+  grpc_connectivity_state_tracker* tracker =
+      inhibit_health_checks ? &c->state_tracker : &c->state_and_health_tracker;
+  grpc_connectivity_state state = grpc_connectivity_state_get(tracker, error);
   gpr_mu_unlock(&c->mu);
   return state;
 }
@@ -533,7 +735,8 @@ static void maybe_start_connecting_locked(grpc_subchannel* c) {
     /* Already connected: don't restart */
     return;
   }
-  if (!grpc_connectivity_state_has_watchers(&c->state_tracker)) {
+  if (!grpc_connectivity_state_has_watchers(&c->state_tracker) &&
+      !grpc_connectivity_state_has_watchers(&c->state_and_health_tracker)) {
     /* Nobody is interested in connecting: so don't just yet */
     return;
   }
@@ -560,16 +763,18 @@ static void maybe_start_connecting_locked(grpc_subchannel* c) {
 
 void grpc_subchannel_notify_on_state_change(
     grpc_subchannel* c, grpc_pollset_set* interested_parties,
-    grpc_connectivity_state* state, grpc_closure* notify) {
+    grpc_connectivity_state* state, grpc_closure* notify,
+    bool inhibit_health_checks) {
+  grpc_connectivity_state_tracker* tracker =
+      inhibit_health_checks ? &c->state_tracker : &c->state_and_health_tracker;
   external_state_watcher* w;
-
   if (state == nullptr) {
     gpr_mu_lock(&c->mu);
     for (w = c->root_external_state_watcher.next;
          w != &c->root_external_state_watcher; w = w->next) {
       if (w->notify == notify) {
-        grpc_connectivity_state_notify_on_state_change(&c->state_tracker,
-                                                       nullptr, &w->closure);
+        grpc_connectivity_state_notify_on_state_change(tracker, nullptr,
+                                                       &w->closure);
       }
     }
     gpr_mu_unlock(&c->mu);
@@ -588,62 +793,12 @@ void grpc_subchannel_notify_on_state_change(
     w->next = &c->root_external_state_watcher;
     w->prev = w->next->prev;
     w->next->prev = w->prev->next = w;
-    grpc_connectivity_state_notify_on_state_change(&c->state_tracker, state,
-                                                   &w->closure);
+    grpc_connectivity_state_notify_on_state_change(tracker, state, &w->closure);
     maybe_start_connecting_locked(c);
     gpr_mu_unlock(&c->mu);
   }
 }
 
-static void on_connected_subchannel_connectivity_changed(void* p,
-                                                         grpc_error* error) {
-  state_watcher* connected_subchannel_watcher = static_cast<state_watcher*>(p);
-  grpc_subchannel* c = connected_subchannel_watcher->subchannel;
-  gpr_mu* mu = &c->mu;
-
-  gpr_mu_lock(mu);
-
-  switch (connected_subchannel_watcher->connectivity_state) {
-    case GRPC_CHANNEL_TRANSIENT_FAILURE:
-    case GRPC_CHANNEL_SHUTDOWN: {
-      if (!c->disconnected && c->connected_subchannel != nullptr) {
-        if (grpc_trace_stream_refcount.enabled()) {
-          gpr_log(GPR_INFO,
-                  "Connected subchannel %p of subchannel %p has gone into %s. "
-                  "Attempting to reconnect.",
-                  c->connected_subchannel.get(), c,
-                  grpc_connectivity_state_name(
-                      connected_subchannel_watcher->connectivity_state));
-        }
-        c->connected_subchannel.reset();
-        set_subchannel_connectivity_state_locked(
-            c, GRPC_CHANNEL_TRANSIENT_FAILURE, GRPC_ERROR_REF(error),
-            "reflect_child");
-        c->backoff_begun = false;
-        c->backoff->Reset();
-        maybe_start_connecting_locked(c);
-      } else {
-        connected_subchannel_watcher->connectivity_state =
-            GRPC_CHANNEL_SHUTDOWN;
-      }
-      break;
-    }
-    default: {
-      set_subchannel_connectivity_state_locked(
-          c, connected_subchannel_watcher->connectivity_state,
-          GRPC_ERROR_REF(error), "reflect_child");
-      GRPC_SUBCHANNEL_WEAK_REF(c, "state_watcher");
-      c->connected_subchannel->NotifyOnStateChange(
-          nullptr, &connected_subchannel_watcher->connectivity_state,
-          &connected_subchannel_watcher->closure);
-      connected_subchannel_watcher = nullptr;
-    }
-  }
-  gpr_mu_unlock(mu);
-  GRPC_SUBCHANNEL_WEAK_UNREF(c, "state_watcher");
-  gpr_free(connected_subchannel_watcher);
-}
-
 static bool publish_transport_locked(grpc_subchannel* c) {
   /* construct channel stack */
   grpc_channel_stack_builder* builder = grpc_channel_stack_builder_create();
@@ -670,17 +825,7 @@ static bool publish_transport_locked(grpc_subchannel* c) {
   intptr_t socket_uuid = c->connecting_result.socket_uuid;
   memset(&c->connecting_result, 0, sizeof(c->connecting_result));
 
-  /* initialize state watcher */
-  state_watcher* connected_subchannel_watcher = static_cast<state_watcher*>(
-      gpr_zalloc(sizeof(*connected_subchannel_watcher)));
-  connected_subchannel_watcher->subchannel = c;
-  connected_subchannel_watcher->connectivity_state = GRPC_CHANNEL_READY;
-  GRPC_CLOSURE_INIT(&connected_subchannel_watcher->closure,
-                    on_connected_subchannel_connectivity_changed,
-                    connected_subchannel_watcher, grpc_schedule_on_exec_ctx);
-
   if (c->disconnected) {
-    gpr_free(connected_subchannel_watcher);
     grpc_channel_stack_destroy(stk);
     gpr_free(stk);
     return false;
@@ -692,17 +837,10 @@ static bool publish_transport_locked(grpc_subchannel* c) {
   gpr_log(GPR_INFO, "New connected subchannel at %p for subchannel %p",
           c->connected_subchannel.get(), c);
 
-  /* setup subchannel watching connected subchannel for changes; subchannel
-     ref for connecting is donated to the state watcher */
-  GRPC_SUBCHANNEL_WEAK_REF(c, "state_watcher");
-  GRPC_SUBCHANNEL_WEAK_UNREF(c, "connecting");
-  c->connected_subchannel->NotifyOnStateChange(
-      c->pollset_set, &connected_subchannel_watcher->connectivity_state,
-      &connected_subchannel_watcher->closure);
-
-  /* signal completion */
-  set_subchannel_connectivity_state_locked(c, GRPC_CHANNEL_READY,
-                                           GRPC_ERROR_NONE, "connected");
+  // Instantiate state watcher.  Will clean itself up.
+  c->connected_subchannel_watcher =
+      grpc_core::MakeOrphanable<grpc_core::ConnectedSubchannelStateWatcher>(c);
+
   return true;
 }
 
@@ -725,6 +863,12 @@ static void on_subchannel_connected(void* arg, grpc_error* error) {
                                "Connect Failed", &error, 1),
                            GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_UNAVAILABLE),
         "connect_failed");
+    grpc_connectivity_state_set(
+        &c->state_and_health_tracker, GRPC_CHANNEL_TRANSIENT_FAILURE,
+        grpc_error_set_int(GRPC_ERROR_CREATE_REFERENCING_FROM_STATIC_STRING(
+                               "Connect Failed", &error, 1),
+                           GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_UNAVAILABLE),
+        "connect_failed");
 
     const char* errmsg = grpc_error_string(error);
     gpr_log(GPR_INFO, "Connect failed: %s", errmsg);
@@ -956,15 +1100,8 @@ void ConnectedSubchannel::Ping(grpc_closure* on_initiate,
 
 grpc_error* ConnectedSubchannel::CreateCall(const CallArgs& args,
                                             grpc_subchannel_call** call) {
-  size_t allocation_size =
-      GPR_ROUND_UP_TO_ALIGNMENT_SIZE(sizeof(grpc_subchannel_call));
-  if (args.parent_data_size > 0) {
-    allocation_size +=
-        GPR_ROUND_UP_TO_ALIGNMENT_SIZE(channel_stack_->call_stack_size) +
-        args.parent_data_size;
-  } else {
-    allocation_size += channel_stack_->call_stack_size;
-  }
+  const size_t allocation_size =
+      GetInitialCallSizeEstimate(args.parent_data_size);
   *call = static_cast<grpc_subchannel_call*>(
       gpr_arena_alloc(args.arena, allocation_size));
   grpc_call_stack* callstk = SUBCHANNEL_CALL_TO_CALL_STACK(*call);
@@ -994,4 +1131,18 @@ grpc_error* ConnectedSubchannel::CreateCall(const CallArgs& args,
   return GRPC_ERROR_NONE;
 }
 
+size_t ConnectedSubchannel::GetInitialCallSizeEstimate(
+    size_t parent_data_size) const {
+  size_t allocation_size =
+      GPR_ROUND_UP_TO_ALIGNMENT_SIZE(sizeof(grpc_subchannel_call));
+  if (parent_data_size > 0) {
+    allocation_size +=
+        GPR_ROUND_UP_TO_ALIGNMENT_SIZE(channel_stack_->call_stack_size) +
+        parent_data_size;
+  } else {
+    allocation_size += channel_stack_->call_stack_size;
+  }
+  return allocation_size;
+}
+
 }  // namespace grpc_core
diff --git a/src/core/ext/filters/client_channel/subchannel.h b/src/core/ext/filters/client_channel/subchannel.h
index c53b13e37e..ec3b4d86e4 100644
--- a/src/core/ext/filters/client_channel/subchannel.h
+++ b/src/core/ext/filters/client_channel/subchannel.h
@@ -103,6 +103,8 @@ class ConnectedSubchannel : public RefCountedWithTracing<ConnectedSubchannel> {
   }
   intptr_t socket_uuid() { return socket_uuid_; }
 
+  size_t GetInitialCallSizeEstimate(size_t parent_data_size) const;
+
  private:
   grpc_channel_stack* channel_stack_;
   // ref counted pointer to the channelz node in this connected subchannel's
@@ -143,13 +145,14 @@ void* grpc_connected_subchannel_call_get_parent_data(
 
 /** poll the current connectivity state of a channel */
 grpc_connectivity_state grpc_subchannel_check_connectivity(
-    grpc_subchannel* channel, grpc_error** error);
+    grpc_subchannel* channel, grpc_error** error, bool inhibit_health_checking);
 
 /** Calls notify when the connectivity state of a channel becomes different
     from *state.  Updates *state with the new state of the channel. */
 void grpc_subchannel_notify_on_state_change(
     grpc_subchannel* channel, grpc_pollset_set* interested_parties,
-    grpc_connectivity_state* state, grpc_closure* notify);
+    grpc_connectivity_state* state, grpc_closure* notify,
+    bool inhibit_health_checks);
 
 /** retrieve the grpc_core::ConnectedSubchannel - or nullptr if not connected
  * (which may happen before it initially connects or during transient failures)
diff --git a/src/core/lib/transport/static_metadata.cc b/src/core/lib/transport/static_metadata.cc
index cdcb9a11d2..4ebe73f82a 100644
--- a/src/core/lib/transport/static_metadata.cc
+++ b/src/core/lib/transport/static_metadata.cc
@@ -63,51 +63,53 @@ static uint8_t g_bytes[] = {
     115, 115, 97,  103, 101, 95,  98,  121, 116, 101, 115, 47,  103, 114, 112,
     99,  46,  108, 98,  46,  118, 49,  46,  76,  111, 97,  100, 66,  97,  108,
     97,  110, 99,  101, 114, 47,  66,  97,  108, 97,  110, 99,  101, 76,  111,
-    97,  100, 100, 101, 102, 108, 97,  116, 101, 103, 122, 105, 112, 115, 116,
-    114, 101, 97,  109, 47,  103, 122, 105, 112, 71,  69,  84,  80,  79,  83,
-    84,  47,  47,  105, 110, 100, 101, 120, 46,  104, 116, 109, 108, 104, 116,
-    116, 112, 104, 116, 116, 112, 115, 50,  48,  48,  50,  48,  52,  50,  48,
-    54,  51,  48,  52,  52,  48,  48,  52,  48,  52,  53,  48,  48,  97,  99,
-    99,  101, 112, 116, 45,  99,  104, 97,  114, 115, 101, 116, 103, 122, 105,
-    112, 44,  32,  100, 101, 102, 108, 97,  116, 101, 97,  99,  99,  101, 112,
-    116, 45,  108, 97,  110, 103, 117, 97,  103, 101, 97,  99,  99,  101, 112,
-    116, 45,  114, 97,  110, 103, 101, 115, 97,  99,  99,  101, 112, 116, 97,
-    99,  99,  101, 115, 115, 45,  99,  111, 110, 116, 114, 111, 108, 45,  97,
-    108, 108, 111, 119, 45,  111, 114, 105, 103, 105, 110, 97,  103, 101, 97,
-    108, 108, 111, 119, 97,  117, 116, 104, 111, 114, 105, 122, 97,  116, 105,
-    111, 110, 99,  97,  99,  104, 101, 45,  99,  111, 110, 116, 114, 111, 108,
-    99,  111, 110, 116, 101, 110, 116, 45,  100, 105, 115, 112, 111, 115, 105,
-    116, 105, 111, 110, 99,  111, 110, 116, 101, 110, 116, 45,  108, 97,  110,
-    103, 117, 97,  103, 101, 99,  111, 110, 116, 101, 110, 116, 45,  108, 101,
-    110, 103, 116, 104, 99,  111, 110, 116, 101, 110, 116, 45,  108, 111, 99,
-    97,  116, 105, 111, 110, 99,  111, 110, 116, 101, 110, 116, 45,  114, 97,
-    110, 103, 101, 99,  111, 111, 107, 105, 101, 100, 97,  116, 101, 101, 116,
-    97,  103, 101, 120, 112, 101, 99,  116, 101, 120, 112, 105, 114, 101, 115,
-    102, 114, 111, 109, 105, 102, 45,  109, 97,  116, 99,  104, 105, 102, 45,
-    109, 111, 100, 105, 102, 105, 101, 100, 45,  115, 105, 110, 99,  101, 105,
-    102, 45,  110, 111, 110, 101, 45,  109, 97,  116, 99,  104, 105, 102, 45,
-    114, 97,  110, 103, 101, 105, 102, 45,  117, 110, 109, 111, 100, 105, 102,
-    105, 101, 100, 45,  115, 105, 110, 99,  101, 108, 97,  115, 116, 45,  109,
-    111, 100, 105, 102, 105, 101, 100, 108, 105, 110, 107, 108, 111, 99,  97,
-    116, 105, 111, 110, 109, 97,  120, 45,  102, 111, 114, 119, 97,  114, 100,
-    115, 112, 114, 111, 120, 121, 45,  97,  117, 116, 104, 101, 110, 116, 105,
-    99,  97,  116, 101, 112, 114, 111, 120, 121, 45,  97,  117, 116, 104, 111,
-    114, 105, 122, 97,  116, 105, 111, 110, 114, 97,  110, 103, 101, 114, 101,
-    102, 101, 114, 101, 114, 114, 101, 102, 114, 101, 115, 104, 114, 101, 116,
-    114, 121, 45,  97,  102, 116, 101, 114, 115, 101, 114, 118, 101, 114, 115,
-    101, 116, 45,  99,  111, 111, 107, 105, 101, 115, 116, 114, 105, 99,  116,
-    45,  116, 114, 97,  110, 115, 112, 111, 114, 116, 45,  115, 101, 99,  117,
-    114, 105, 116, 121, 116, 114, 97,  110, 115, 102, 101, 114, 45,  101, 110,
-    99,  111, 100, 105, 110, 103, 118, 97,  114, 121, 118, 105, 97,  119, 119,
-    119, 45,  97,  117, 116, 104, 101, 110, 116, 105, 99,  97,  116, 101, 48,
-    105, 100, 101, 110, 116, 105, 116, 121, 116, 114, 97,  105, 108, 101, 114,
-    115, 97,  112, 112, 108, 105, 99,  97,  116, 105, 111, 110, 47,  103, 114,
-    112, 99,  103, 114, 112, 99,  80,  85,  84,  108, 98,  45,  99,  111, 115,
-    116, 45,  98,  105, 110, 105, 100, 101, 110, 116, 105, 116, 121, 44,  100,
-    101, 102, 108, 97,  116, 101, 105, 100, 101, 110, 116, 105, 116, 121, 44,
-    103, 122, 105, 112, 100, 101, 102, 108, 97,  116, 101, 44,  103, 122, 105,
-    112, 105, 100, 101, 110, 116, 105, 116, 121, 44,  100, 101, 102, 108, 97,
-    116, 101, 44,  103, 122, 105, 112};
+    97,  100, 47,  103, 114, 112, 99,  46,  104, 101, 97,  108, 116, 104, 46,
+    118, 49,  46,  72,  101, 97,  108, 116, 104, 47,  87,  97,  116, 99,  104,
+    100, 101, 102, 108, 97,  116, 101, 103, 122, 105, 112, 115, 116, 114, 101,
+    97,  109, 47,  103, 122, 105, 112, 71,  69,  84,  80,  79,  83,  84,  47,
+    47,  105, 110, 100, 101, 120, 46,  104, 116, 109, 108, 104, 116, 116, 112,
+    104, 116, 116, 112, 115, 50,  48,  48,  50,  48,  52,  50,  48,  54,  51,
+    48,  52,  52,  48,  48,  52,  48,  52,  53,  48,  48,  97,  99,  99,  101,
+    112, 116, 45,  99,  104, 97,  114, 115, 101, 116, 103, 122, 105, 112, 44,
+    32,  100, 101, 102, 108, 97,  116, 101, 97,  99,  99,  101, 112, 116, 45,
+    108, 97,  110, 103, 117, 97,  103, 101, 97,  99,  99,  101, 112, 116, 45,
+    114, 97,  110, 103, 101, 115, 97,  99,  99,  101, 112, 116, 97,  99,  99,
+    101, 115, 115, 45,  99,  111, 110, 116, 114, 111, 108, 45,  97,  108, 108,
+    111, 119, 45,  111, 114, 105, 103, 105, 110, 97,  103, 101, 97,  108, 108,
+    111, 119, 97,  117, 116, 104, 111, 114, 105, 122, 97,  116, 105, 111, 110,
+    99,  97,  99,  104, 101, 45,  99,  111, 110, 116, 114, 111, 108, 99,  111,
+    110, 116, 101, 110, 116, 45,  100, 105, 115, 112, 111, 115, 105, 116, 105,
+    111, 110, 99,  111, 110, 116, 101, 110, 116, 45,  108, 97,  110, 103, 117,
+    97,  103, 101, 99,  111, 110, 116, 101, 110, 116, 45,  108, 101, 110, 103,
+    116, 104, 99,  111, 110, 116, 101, 110, 116, 45,  108, 111, 99,  97,  116,
+    105, 111, 110, 99,  111, 110, 116, 101, 110, 116, 45,  114, 97,  110, 103,
+    101, 99,  111, 111, 107, 105, 101, 100, 97,  116, 101, 101, 116, 97,  103,
+    101, 120, 112, 101, 99,  116, 101, 120, 112, 105, 114, 101, 115, 102, 114,
+    111, 109, 105, 102, 45,  109, 97,  116, 99,  104, 105, 102, 45,  109, 111,
+    100, 105, 102, 105, 101, 100, 45,  115, 105, 110, 99,  101, 105, 102, 45,
+    110, 111, 110, 101, 45,  109, 97,  116, 99,  104, 105, 102, 45,  114, 97,
+    110, 103, 101, 105, 102, 45,  117, 110, 109, 111, 100, 105, 102, 105, 101,
+    100, 45,  115, 105, 110, 99,  101, 108, 97,  115, 116, 45,  109, 111, 100,
+    105, 102, 105, 101, 100, 108, 105, 110, 107, 108, 111, 99,  97,  116, 105,
+    111, 110, 109, 97,  120, 45,  102, 111, 114, 119, 97,  114, 100, 115, 112,
+    114, 111, 120, 121, 45,  97,  117, 116, 104, 101, 110, 116, 105, 99,  97,
+    116, 101, 112, 114, 111, 120, 121, 45,  97,  117, 116, 104, 111, 114, 105,
+    122, 97,  116, 105, 111, 110, 114, 97,  110, 103, 101, 114, 101, 102, 101,
+    114, 101, 114, 114, 101, 102, 114, 101, 115, 104, 114, 101, 116, 114, 121,
+    45,  97,  102, 116, 101, 114, 115, 101, 114, 118, 101, 114, 115, 101, 116,
+    45,  99,  111, 111, 107, 105, 101, 115, 116, 114, 105, 99,  116, 45,  116,
+    114, 97,  110, 115, 112, 111, 114, 116, 45,  115, 101, 99,  117, 114, 105,
+    116, 121, 116, 114, 97,  110, 115, 102, 101, 114, 45,  101, 110, 99,  111,
+    100, 105, 110, 103, 118, 97,  114, 121, 118, 105, 97,  119, 119, 119, 45,
+    97,  117, 116, 104, 101, 110, 116, 105, 99,  97,  116, 101, 48,  105, 100,
+    101, 110, 116, 105, 116, 121, 116, 114, 97,  105, 108, 101, 114, 115, 97,
+    112, 112, 108, 105, 99,  97,  116, 105, 111, 110, 47,  103, 114, 112, 99,
+    103, 114, 112, 99,  80,  85,  84,  108, 98,  45,  99,  111, 115, 116, 45,
+    98,  105, 110, 105, 100, 101, 110, 116, 105, 116, 121, 44,  100, 101, 102,
+    108, 97,  116, 101, 105, 100, 101, 110, 116, 105, 116, 121, 44,  103, 122,
+    105, 112, 100, 101, 102, 108, 97,  116, 101, 44,  103, 122, 105, 112, 105,
+    100, 101, 110, 116, 105, 116, 121, 44,  100, 101, 102, 108, 97,  116, 101,
+    44,  103, 122, 105, 112};
 
 static void static_ref(void* unused) {}
 static void static_unref(void* unused) {}
@@ -224,6 +226,7 @@ grpc_slice_refcount grpc_static_metadata_refcounts[GRPC_STATIC_MDSTR_COUNT] = {
     {&grpc_static_metadata_vtable, &static_sub_refcnt},
     {&grpc_static_metadata_vtable, &static_sub_refcnt},
     {&grpc_static_metadata_vtable, &static_sub_refcnt},
+    {&grpc_static_metadata_vtable, &static_sub_refcnt},
 };
 
 const grpc_slice grpc_static_slice_table[GRPC_STATIC_MDSTR_COUNT] = {
@@ -262,76 +265,77 @@ const grpc_slice grpc_static_slice_table[GRPC_STATIC_MDSTR_COUNT] = {
     {&grpc_static_metadata_refcounts[32], {{g_bytes + 385, 30}}},
     {&grpc_static_metadata_refcounts[33], {{g_bytes + 415, 31}}},
     {&grpc_static_metadata_refcounts[34], {{g_bytes + 446, 36}}},
-    {&grpc_static_metadata_refcounts[35], {{g_bytes + 482, 7}}},
-    {&grpc_static_metadata_refcounts[36], {{g_bytes + 489, 4}}},
-    {&grpc_static_metadata_refcounts[37], {{g_bytes + 493, 11}}},
-    {&grpc_static_metadata_refcounts[38], {{g_bytes + 504, 3}}},
-    {&grpc_static_metadata_refcounts[39], {{g_bytes + 507, 4}}},
-    {&grpc_static_metadata_refcounts[40], {{g_bytes + 511, 1}}},
-    {&grpc_static_metadata_refcounts[41], {{g_bytes + 512, 11}}},
-    {&grpc_static_metadata_refcounts[42], {{g_bytes + 523, 4}}},
-    {&grpc_static_metadata_refcounts[43], {{g_bytes + 527, 5}}},
-    {&grpc_static_metadata_refcounts[44], {{g_bytes + 532, 3}}},
-    {&grpc_static_metadata_refcounts[45], {{g_bytes + 535, 3}}},
-    {&grpc_static_metadata_refcounts[46], {{g_bytes + 538, 3}}},
-    {&grpc_static_metadata_refcounts[47], {{g_bytes + 541, 3}}},
-    {&grpc_static_metadata_refcounts[48], {{g_bytes + 544, 3}}},
-    {&grpc_static_metadata_refcounts[49], {{g_bytes + 547, 3}}},
-    {&grpc_static_metadata_refcounts[50], {{g_bytes + 550, 3}}},
-    {&grpc_static_metadata_refcounts[51], {{g_bytes + 553, 14}}},
-    {&grpc_static_metadata_refcounts[52], {{g_bytes + 567, 13}}},
-    {&grpc_static_metadata_refcounts[53], {{g_bytes + 580, 15}}},
-    {&grpc_static_metadata_refcounts[54], {{g_bytes + 595, 13}}},
-    {&grpc_static_metadata_refcounts[55], {{g_bytes + 608, 6}}},
-    {&grpc_static_metadata_refcounts[56], {{g_bytes + 614, 27}}},
-    {&grpc_static_metadata_refcounts[57], {{g_bytes + 641, 3}}},
-    {&grpc_static_metadata_refcounts[58], {{g_bytes + 644, 5}}},
-    {&grpc_static_metadata_refcounts[59], {{g_bytes + 649, 13}}},
-    {&grpc_static_metadata_refcounts[60], {{g_bytes + 662, 13}}},
-    {&grpc_static_metadata_refcounts[61], {{g_bytes + 675, 19}}},
-    {&grpc_static_metadata_refcounts[62], {{g_bytes + 694, 16}}},
-    {&grpc_static_metadata_refcounts[63], {{g_bytes + 710, 14}}},
-    {&grpc_static_metadata_refcounts[64], {{g_bytes + 724, 16}}},
-    {&grpc_static_metadata_refcounts[65], {{g_bytes + 740, 13}}},
-    {&grpc_static_metadata_refcounts[66], {{g_bytes + 753, 6}}},
-    {&grpc_static_metadata_refcounts[67], {{g_bytes + 759, 4}}},
-    {&grpc_static_metadata_refcounts[68], {{g_bytes + 763, 4}}},
-    {&grpc_static_metadata_refcounts[69], {{g_bytes + 767, 6}}},
-    {&grpc_static_metadata_refcounts[70], {{g_bytes + 773, 7}}},
-    {&grpc_static_metadata_refcounts[71], {{g_bytes + 780, 4}}},
-    {&grpc_static_metadata_refcounts[72], {{g_bytes + 784, 8}}},
-    {&grpc_static_metadata_refcounts[73], {{g_bytes + 792, 17}}},
-    {&grpc_static_metadata_refcounts[74], {{g_bytes + 809, 13}}},
-    {&grpc_static_metadata_refcounts[75], {{g_bytes + 822, 8}}},
-    {&grpc_static_metadata_refcounts[76], {{g_bytes + 830, 19}}},
-    {&grpc_static_metadata_refcounts[77], {{g_bytes + 849, 13}}},
-    {&grpc_static_metadata_refcounts[78], {{g_bytes + 862, 4}}},
-    {&grpc_static_metadata_refcounts[79], {{g_bytes + 866, 8}}},
-    {&grpc_static_metadata_refcounts[80], {{g_bytes + 874, 12}}},
-    {&grpc_static_metadata_refcounts[81], {{g_bytes + 886, 18}}},
-    {&grpc_static_metadata_refcounts[82], {{g_bytes + 904, 19}}},
-    {&grpc_static_metadata_refcounts[83], {{g_bytes + 923, 5}}},
-    {&grpc_static_metadata_refcounts[84], {{g_bytes + 928, 7}}},
-    {&grpc_static_metadata_refcounts[85], {{g_bytes + 935, 7}}},
-    {&grpc_static_metadata_refcounts[86], {{g_bytes + 942, 11}}},
-    {&grpc_static_metadata_refcounts[87], {{g_bytes + 953, 6}}},
-    {&grpc_static_metadata_refcounts[88], {{g_bytes + 959, 10}}},
-    {&grpc_static_metadata_refcounts[89], {{g_bytes + 969, 25}}},
-    {&grpc_static_metadata_refcounts[90], {{g_bytes + 994, 17}}},
-    {&grpc_static_metadata_refcounts[91], {{g_bytes + 1011, 4}}},
-    {&grpc_static_metadata_refcounts[92], {{g_bytes + 1015, 3}}},
-    {&grpc_static_metadata_refcounts[93], {{g_bytes + 1018, 16}}},
-    {&grpc_static_metadata_refcounts[94], {{g_bytes + 1034, 1}}},
-    {&grpc_static_metadata_refcounts[95], {{g_bytes + 1035, 8}}},
-    {&grpc_static_metadata_refcounts[96], {{g_bytes + 1043, 8}}},
-    {&grpc_static_metadata_refcounts[97], {{g_bytes + 1051, 16}}},
-    {&grpc_static_metadata_refcounts[98], {{g_bytes + 1067, 4}}},
-    {&grpc_static_metadata_refcounts[99], {{g_bytes + 1071, 3}}},
-    {&grpc_static_metadata_refcounts[100], {{g_bytes + 1074, 11}}},
-    {&grpc_static_metadata_refcounts[101], {{g_bytes + 1085, 16}}},
-    {&grpc_static_metadata_refcounts[102], {{g_bytes + 1101, 13}}},
-    {&grpc_static_metadata_refcounts[103], {{g_bytes + 1114, 12}}},
-    {&grpc_static_metadata_refcounts[104], {{g_bytes + 1126, 21}}},
+    {&grpc_static_metadata_refcounts[35], {{g_bytes + 482, 28}}},
+    {&grpc_static_metadata_refcounts[36], {{g_bytes + 510, 7}}},
+    {&grpc_static_metadata_refcounts[37], {{g_bytes + 517, 4}}},
+    {&grpc_static_metadata_refcounts[38], {{g_bytes + 521, 11}}},
+    {&grpc_static_metadata_refcounts[39], {{g_bytes + 532, 3}}},
+    {&grpc_static_metadata_refcounts[40], {{g_bytes + 535, 4}}},
+    {&grpc_static_metadata_refcounts[41], {{g_bytes + 539, 1}}},
+    {&grpc_static_metadata_refcounts[42], {{g_bytes + 540, 11}}},
+    {&grpc_static_metadata_refcounts[43], {{g_bytes + 551, 4}}},
+    {&grpc_static_metadata_refcounts[44], {{g_bytes + 555, 5}}},
+    {&grpc_static_metadata_refcounts[45], {{g_bytes + 560, 3}}},
+    {&grpc_static_metadata_refcounts[46], {{g_bytes + 563, 3}}},
+    {&grpc_static_metadata_refcounts[47], {{g_bytes + 566, 3}}},
+    {&grpc_static_metadata_refcounts[48], {{g_bytes + 569, 3}}},
+    {&grpc_static_metadata_refcounts[49], {{g_bytes + 572, 3}}},
+    {&grpc_static_metadata_refcounts[50], {{g_bytes + 575, 3}}},
+    {&grpc_static_metadata_refcounts[51], {{g_bytes + 578, 3}}},
+    {&grpc_static_metadata_refcounts[52], {{g_bytes + 581, 14}}},
+    {&grpc_static_metadata_refcounts[53], {{g_bytes + 595, 13}}},
+    {&grpc_static_metadata_refcounts[54], {{g_bytes + 608, 15}}},
+    {&grpc_static_metadata_refcounts[55], {{g_bytes + 623, 13}}},
+    {&grpc_static_metadata_refcounts[56], {{g_bytes + 636, 6}}},
+    {&grpc_static_metadata_refcounts[57], {{g_bytes + 642, 27}}},
+    {&grpc_static_metadata_refcounts[58], {{g_bytes + 669, 3}}},
+    {&grpc_static_metadata_refcounts[59], {{g_bytes + 672, 5}}},
+    {&grpc_static_metadata_refcounts[60], {{g_bytes + 677, 13}}},
+    {&grpc_static_metadata_refcounts[61], {{g_bytes + 690, 13}}},
+    {&grpc_static_metadata_refcounts[62], {{g_bytes + 703, 19}}},
+    {&grpc_static_metadata_refcounts[63], {{g_bytes + 722, 16}}},
+    {&grpc_static_metadata_refcounts[64], {{g_bytes + 738, 14}}},
+    {&grpc_static_metadata_refcounts[65], {{g_bytes + 752, 16}}},
+    {&grpc_static_metadata_refcounts[66], {{g_bytes + 768, 13}}},
+    {&grpc_static_metadata_refcounts[67], {{g_bytes + 781, 6}}},
+    {&grpc_static_metadata_refcounts[68], {{g_bytes + 787, 4}}},
+    {&grpc_static_metadata_refcounts[69], {{g_bytes + 791, 4}}},
+    {&grpc_static_metadata_refcounts[70], {{g_bytes + 795, 6}}},
+    {&grpc_static_metadata_refcounts[71], {{g_bytes + 801, 7}}},
+    {&grpc_static_metadata_refcounts[72], {{g_bytes + 808, 4}}},
+    {&grpc_static_metadata_refcounts[73], {{g_bytes + 812, 8}}},
+    {&grpc_static_metadata_refcounts[74], {{g_bytes + 820, 17}}},
+    {&grpc_static_metadata_refcounts[75], {{g_bytes + 837, 13}}},
+    {&grpc_static_metadata_refcounts[76], {{g_bytes + 850, 8}}},
+    {&grpc_static_metadata_refcounts[77], {{g_bytes + 858, 19}}},
+    {&grpc_static_metadata_refcounts[78], {{g_bytes + 877, 13}}},
+    {&grpc_static_metadata_refcounts[79], {{g_bytes + 890, 4}}},
+    {&grpc_static_metadata_refcounts[80], {{g_bytes + 894, 8}}},
+    {&grpc_static_metadata_refcounts[81], {{g_bytes + 902, 12}}},
+    {&grpc_static_metadata_refcounts[82], {{g_bytes + 914, 18}}},
+    {&grpc_static_metadata_refcounts[83], {{g_bytes + 932, 19}}},
+    {&grpc_static_metadata_refcounts[84], {{g_bytes + 951, 5}}},
+    {&grpc_static_metadata_refcounts[85], {{g_bytes + 956, 7}}},
+    {&grpc_static_metadata_refcounts[86], {{g_bytes + 963, 7}}},
+    {&grpc_static_metadata_refcounts[87], {{g_bytes + 970, 11}}},
+    {&grpc_static_metadata_refcounts[88], {{g_bytes + 981, 6}}},
+    {&grpc_static_metadata_refcounts[89], {{g_bytes + 987, 10}}},
+    {&grpc_static_metadata_refcounts[90], {{g_bytes + 997, 25}}},
+    {&grpc_static_metadata_refcounts[91], {{g_bytes + 1022, 17}}},
+    {&grpc_static_metadata_refcounts[92], {{g_bytes + 1039, 4}}},
+    {&grpc_static_metadata_refcounts[93], {{g_bytes + 1043, 3}}},
+    {&grpc_static_metadata_refcounts[94], {{g_bytes + 1046, 16}}},
+    {&grpc_static_metadata_refcounts[95], {{g_bytes + 1062, 1}}},
+    {&grpc_static_metadata_refcounts[96], {{g_bytes + 1063, 8}}},
+    {&grpc_static_metadata_refcounts[97], {{g_bytes + 1071, 8}}},
+    {&grpc_static_metadata_refcounts[98], {{g_bytes + 1079, 16}}},
+    {&grpc_static_metadata_refcounts[99], {{g_bytes + 1095, 4}}},
+    {&grpc_static_metadata_refcounts[100], {{g_bytes + 1099, 3}}},
+    {&grpc_static_metadata_refcounts[101], {{g_bytes + 1102, 11}}},
+    {&grpc_static_metadata_refcounts[102], {{g_bytes + 1113, 16}}},
+    {&grpc_static_metadata_refcounts[103], {{g_bytes + 1129, 13}}},
+    {&grpc_static_metadata_refcounts[104], {{g_bytes + 1142, 12}}},
+    {&grpc_static_metadata_refcounts[105], {{g_bytes + 1154, 21}}},
 };
 
 uintptr_t grpc_static_mdelem_user_data[GRPC_STATIC_MDELEM_COUNT] = {
@@ -341,17 +345,17 @@ uintptr_t grpc_static_mdelem_user_data[GRPC_STATIC_MDELEM_COUNT] = {
     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 4, 4, 6, 6, 8, 8, 2, 4, 4};
 
 static const int8_t elems_r[] = {
-    15, 9,   -8, 0,  2,  -44, -78, 17, 0,   6,   -8,  0,   0,  0,  6,
-    -5, -10, 0,  0,  -2, -3,  -4,  0,  0,   0,   0,   0,   0,  0,  0,
-    0,  0,   0,  0,  0,  0,   0,   0,  0,   0,   0,   0,   0,  0,  0,
-    0,  0,   0,  0,  0,  0,   -63, 0,  -46, -68, -69, -53, 0,  31, 30,
-    29, 29,  28, 27, 26, 25,  24,  23, 22,  21,  20,  19,  18, 17, 18,
-    17, 16,  15, 14, 13, 12,  11,  10, 9,   8,   7,   6,   5,  4,  3,
-    2,  3,   3,  2,  6,  0,   0,   0,  0,   0,   0,   -5,  0};
+    16, 11,  -8, 0,  3,  -42, -81, -43, 0,  6,   -8,  0,   0,   0,  -7,
+    -3, -10, 0,  0,  0,  -1,  -2,  0,   0,  0,   0,   0,   0,   0,  0,
+    0,  0,   0,  0,  0,  0,   0,   0,   0,  0,   0,   0,   0,   0,  0,
+    0,  0,   0,  0,  0,  0,   0,   -63, 0,  -47, -68, -69, -70, 0,  33,
+    33, 32,  31, 30, 29, 28,  27,  26,  25, 24,  23,  22,  21,  20, 20,
+    19, 18,  17, 16, 15, 14,  13,  12,  11, 10,  9,   8,   7,   6,  5,
+    4,  4,   4,  3,  10, 9,   0,   0,   0,  0,   0,   0,   -3,  0};
 static uint32_t elems_phash(uint32_t i) {
-  i -= 40;
-  uint32_t x = i % 103;
-  uint32_t y = i / 103;
+  i -= 41;
+  uint32_t x = i % 104;
+  uint32_t y = i / 104;
   uint32_t h = x;
   if (y < GPR_ARRAY_SIZE(elems_r)) {
     uint32_t delta = (uint32_t)elems_r[y];
@@ -361,29 +365,29 @@ static uint32_t elems_phash(uint32_t i) {
 }
 
 static const uint16_t elem_keys[] = {
-    254,  255,  256,  257,  258,  259,  260,  1085, 1086, 143,   144,  1709,
-    462,  463,  1604, 40,   41,   761,  1716, 980,  981,  1611,  621,  1499,
-    760,  2024, 2129, 2234, 5384, 5699, 5804, 6014, 6119, 6224,  1732, 6329,
-    6434, 6539, 6644, 6749, 6854, 6959, 7064, 7169, 7274, 7379,  7484, 7589,
-    5909, 5594, 7694, 7799, 7904, 8009, 8114, 8219, 8324, 8429,  8534, 8639,
-    8744, 8849, 8954, 9059, 9164, 9269, 9374, 1145, 518,  9479,  204,  9584,
-    9689, 1151, 1152, 1153, 1154, 1775, 9794, 1040, 1670, 10529, 0,    0,
-    1782, 829,  0,    0,    0,    0,    344,  1567, 0,    0,     0,    0,
-    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,     0,    0,
-    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,     0,    0,
-    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,     0,    0,
-    0};
+    257,  258,  259,  260,  261,  262,  263,  1096, 1097, 1513, 1725, 145,
+    146,  467,  468,  1619, 41,   42,   1733, 990,  991,  767,  768,  1627,
+    627,  837,  2043, 2149, 2255, 5541, 5859, 5965, 6071, 6177, 1749, 6283,
+    6389, 6495, 6601, 6707, 6813, 6919, 7025, 7131, 7237, 7343, 7449, 7555,
+    7661, 5753, 7767, 7873, 7979, 8085, 8191, 8297, 8403, 8509, 8615, 8721,
+    8827, 8933, 9039, 9145, 9251, 9357, 9463, 1156, 9569, 523,  9675, 9781,
+    206,  1162, 1163, 1164, 1165, 1792, 1582, 1050, 9887, 9993, 1686, 10735,
+    1799, 0,    0,    0,    0,    0,    347,  0,    0,    0,    0,    0,
+    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
+    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
+    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
+    0,    0,    0,    0};
 static const uint8_t elem_idxs[] = {
-    7,  8,  9,   10,  11, 12, 13,  77,  79,  1,   2,  71, 5,  6,  25, 3,
-    4,  63, 84,  66,  65, 73, 67,  30,  62,  57,  37, 74, 14, 17, 18, 20,
-    21, 22, 15,  23,  24, 26, 27,  28,  29,  31,  32, 33, 34, 35, 36, 38,
-    19, 16, 39,  40,  41, 42, 43,  44,  45,  46,  47, 48, 49, 50, 51, 52,
-    53, 54, 55,  76,  69, 56, 70,  58,  59,  78,  80, 81, 82, 83, 60, 64,
-    72, 75, 255, 255, 85, 61, 255, 255, 255, 255, 0,  68};
+    7,  8,  9,  10, 11, 12,  13,  77,  79,  30,  71, 1,  2,  5,  6,  25,
+    3,  4,  84, 66, 65, 62,  63,  73,  67,  61,  57, 37, 74, 14, 17, 18,
+    19, 20, 15, 21, 22, 23,  24,  26,  27,  28,  29, 31, 32, 33, 34, 35,
+    36, 16, 38, 39, 40, 41,  42,  43,  44,  45,  46, 47, 48, 49, 50, 51,
+    52, 53, 54, 76, 55, 69,  56,  58,  70,  78,  80, 81, 82, 83, 68, 64,
+    59, 60, 72, 75, 85, 255, 255, 255, 255, 255, 0};
 
 grpc_mdelem grpc_static_mdelem_for_static_strings(int a, int b) {
   if (a == -1 || b == -1) return GRPC_MDNULL;
-  uint32_t k = (uint32_t)(a * 105 + b);
+  uint32_t k = (uint32_t)(a * 106 + b);
   uint32_t h = elems_phash(k);
   return h < GPR_ARRAY_SIZE(elem_keys) && elem_keys[h] == k &&
                  elem_idxs[h] != 255
@@ -396,175 +400,175 @@ grpc_mdelem_data grpc_static_mdelem_table[GRPC_STATIC_MDELEM_COUNT] = {
     {{&grpc_static_metadata_refcounts[3], {{g_bytes + 19, 10}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
     {{&grpc_static_metadata_refcounts[1], {{g_bytes + 5, 7}}},
-     {&grpc_static_metadata_refcounts[38], {{g_bytes + 504, 3}}}},
+     {&grpc_static_metadata_refcounts[39], {{g_bytes + 532, 3}}}},
     {{&grpc_static_metadata_refcounts[1], {{g_bytes + 5, 7}}},
-     {&grpc_static_metadata_refcounts[39], {{g_bytes + 507, 4}}}},
+     {&grpc_static_metadata_refcounts[40], {{g_bytes + 535, 4}}}},
     {{&grpc_static_metadata_refcounts[0], {{g_bytes + 0, 5}}},
-     {&grpc_static_metadata_refcounts[40], {{g_bytes + 511, 1}}}},
+     {&grpc_static_metadata_refcounts[41], {{g_bytes + 539, 1}}}},
     {{&grpc_static_metadata_refcounts[0], {{g_bytes + 0, 5}}},
-     {&grpc_static_metadata_refcounts[41], {{g_bytes + 512, 11}}}},
+     {&grpc_static_metadata_refcounts[42], {{g_bytes + 540, 11}}}},
     {{&grpc_static_metadata_refcounts[4], {{g_bytes + 29, 7}}},
-     {&grpc_static_metadata_refcounts[42], {{g_bytes + 523, 4}}}},
+     {&grpc_static_metadata_refcounts[43], {{g_bytes + 551, 4}}}},
     {{&grpc_static_metadata_refcounts[4], {{g_bytes + 29, 7}}},
-     {&grpc_static_metadata_refcounts[43], {{g_bytes + 527, 5}}}},
+     {&grpc_static_metadata_refcounts[44], {{g_bytes + 555, 5}}}},
     {{&grpc_static_metadata_refcounts[2], {{g_bytes + 12, 7}}},
-     {&grpc_static_metadata_refcounts[44], {{g_bytes + 532, 3}}}},
+     {&grpc_static_metadata_refcounts[45], {{g_bytes + 560, 3}}}},
     {{&grpc_static_metadata_refcounts[2], {{g_bytes + 12, 7}}},
-     {&grpc_static_metadata_refcounts[45], {{g_bytes + 535, 3}}}},
+     {&grpc_static_metadata_refcounts[46], {{g_bytes + 563, 3}}}},
     {{&grpc_static_metadata_refcounts[2], {{g_bytes + 12, 7}}},
-     {&grpc_static_metadata_refcounts[46], {{g_bytes + 538, 3}}}},
+     {&grpc_static_metadata_refcounts[47], {{g_bytes + 566, 3}}}},
     {{&grpc_static_metadata_refcounts[2], {{g_bytes + 12, 7}}},
-     {&grpc_static_metadata_refcounts[47], {{g_bytes + 541, 3}}}},
+     {&grpc_static_metadata_refcounts[48], {{g_bytes + 569, 3}}}},
     {{&grpc_static_metadata_refcounts[2], {{g_bytes + 12, 7}}},
-     {&grpc_static_metadata_refcounts[48], {{g_bytes + 544, 3}}}},
+     {&grpc_static_metadata_refcounts[49], {{g_bytes + 572, 3}}}},
     {{&grpc_static_metadata_refcounts[2], {{g_bytes + 12, 7}}},
-     {&grpc_static_metadata_refcounts[49], {{g_bytes + 547, 3}}}},
+     {&grpc_static_metadata_refcounts[50], {{g_bytes + 575, 3}}}},
     {{&grpc_static_metadata_refcounts[2], {{g_bytes + 12, 7}}},
-     {&grpc_static_metadata_refcounts[50], {{g_bytes + 550, 3}}}},
-    {{&grpc_static_metadata_refcounts[51], {{g_bytes + 553, 14}}},
+     {&grpc_static_metadata_refcounts[51], {{g_bytes + 578, 3}}}},
+    {{&grpc_static_metadata_refcounts[52], {{g_bytes + 581, 14}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
     {{&grpc_static_metadata_refcounts[16], {{g_bytes + 186, 15}}},
-     {&grpc_static_metadata_refcounts[52], {{g_bytes + 567, 13}}}},
-    {{&grpc_static_metadata_refcounts[53], {{g_bytes + 580, 15}}},
+     {&grpc_static_metadata_refcounts[53], {{g_bytes + 595, 13}}}},
+    {{&grpc_static_metadata_refcounts[54], {{g_bytes + 608, 15}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[54], {{g_bytes + 595, 13}}},
+    {{&grpc_static_metadata_refcounts[55], {{g_bytes + 623, 13}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[55], {{g_bytes + 608, 6}}},
+    {{&grpc_static_metadata_refcounts[56], {{g_bytes + 636, 6}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[56], {{g_bytes + 614, 27}}},
+    {{&grpc_static_metadata_refcounts[57], {{g_bytes + 642, 27}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[57], {{g_bytes + 641, 3}}},
+    {{&grpc_static_metadata_refcounts[58], {{g_bytes + 669, 3}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[58], {{g_bytes + 644, 5}}},
+    {{&grpc_static_metadata_refcounts[59], {{g_bytes + 672, 5}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[59], {{g_bytes + 649, 13}}},
+    {{&grpc_static_metadata_refcounts[60], {{g_bytes + 677, 13}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[60], {{g_bytes + 662, 13}}},
+    {{&grpc_static_metadata_refcounts[61], {{g_bytes + 690, 13}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[61], {{g_bytes + 675, 19}}},
+    {{&grpc_static_metadata_refcounts[62], {{g_bytes + 703, 19}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
     {{&grpc_static_metadata_refcounts[15], {{g_bytes + 170, 16}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[62], {{g_bytes + 694, 16}}},
+    {{&grpc_static_metadata_refcounts[63], {{g_bytes + 722, 16}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[63], {{g_bytes + 710, 14}}},
+    {{&grpc_static_metadata_refcounts[64], {{g_bytes + 738, 14}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[64], {{g_bytes + 724, 16}}},
+    {{&grpc_static_metadata_refcounts[65], {{g_bytes + 752, 16}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[65], {{g_bytes + 740, 13}}},
+    {{&grpc_static_metadata_refcounts[66], {{g_bytes + 768, 13}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
     {{&grpc_static_metadata_refcounts[14], {{g_bytes + 158, 12}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[66], {{g_bytes + 753, 6}}},
+    {{&grpc_static_metadata_refcounts[67], {{g_bytes + 781, 6}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[67], {{g_bytes + 759, 4}}},
+    {{&grpc_static_metadata_refcounts[68], {{g_bytes + 787, 4}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[68], {{g_bytes + 763, 4}}},
+    {{&grpc_static_metadata_refcounts[69], {{g_bytes + 791, 4}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[69], {{g_bytes + 767, 6}}},
+    {{&grpc_static_metadata_refcounts[70], {{g_bytes + 795, 6}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[70], {{g_bytes + 773, 7}}},
+    {{&grpc_static_metadata_refcounts[71], {{g_bytes + 801, 7}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[71], {{g_bytes + 780, 4}}},
+    {{&grpc_static_metadata_refcounts[72], {{g_bytes + 808, 4}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
     {{&grpc_static_metadata_refcounts[20], {{g_bytes + 278, 4}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[72], {{g_bytes + 784, 8}}},
+    {{&grpc_static_metadata_refcounts[73], {{g_bytes + 812, 8}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[73], {{g_bytes + 792, 17}}},
+    {{&grpc_static_metadata_refcounts[74], {{g_bytes + 820, 17}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[74], {{g_bytes + 809, 13}}},
+    {{&grpc_static_metadata_refcounts[75], {{g_bytes + 837, 13}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[75], {{g_bytes + 822, 8}}},
+    {{&grpc_static_metadata_refcounts[76], {{g_bytes + 850, 8}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[76], {{g_bytes + 830, 19}}},
+    {{&grpc_static_metadata_refcounts[77], {{g_bytes + 858, 19}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[77], {{g_bytes + 849, 13}}},
+    {{&grpc_static_metadata_refcounts[78], {{g_bytes + 877, 13}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[78], {{g_bytes + 862, 4}}},
+    {{&grpc_static_metadata_refcounts[79], {{g_bytes + 890, 4}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[79], {{g_bytes + 866, 8}}},
+    {{&grpc_static_metadata_refcounts[80], {{g_bytes + 894, 8}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[80], {{g_bytes + 874, 12}}},
+    {{&grpc_static_metadata_refcounts[81], {{g_bytes + 902, 12}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[81], {{g_bytes + 886, 18}}},
+    {{&grpc_static_metadata_refcounts[82], {{g_bytes + 914, 18}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[82], {{g_bytes + 904, 19}}},
+    {{&grpc_static_metadata_refcounts[83], {{g_bytes + 932, 19}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[83], {{g_bytes + 923, 5}}},
+    {{&grpc_static_metadata_refcounts[84], {{g_bytes + 951, 5}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[84], {{g_bytes + 928, 7}}},
+    {{&grpc_static_metadata_refcounts[85], {{g_bytes + 956, 7}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[85], {{g_bytes + 935, 7}}},
+    {{&grpc_static_metadata_refcounts[86], {{g_bytes + 963, 7}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[86], {{g_bytes + 942, 11}}},
+    {{&grpc_static_metadata_refcounts[87], {{g_bytes + 970, 11}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[87], {{g_bytes + 953, 6}}},
+    {{&grpc_static_metadata_refcounts[88], {{g_bytes + 981, 6}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[88], {{g_bytes + 959, 10}}},
+    {{&grpc_static_metadata_refcounts[89], {{g_bytes + 987, 10}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[89], {{g_bytes + 969, 25}}},
+    {{&grpc_static_metadata_refcounts[90], {{g_bytes + 997, 25}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[90], {{g_bytes + 994, 17}}},
+    {{&grpc_static_metadata_refcounts[91], {{g_bytes + 1022, 17}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
     {{&grpc_static_metadata_refcounts[19], {{g_bytes + 268, 10}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[91], {{g_bytes + 1011, 4}}},
+    {{&grpc_static_metadata_refcounts[92], {{g_bytes + 1039, 4}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[92], {{g_bytes + 1015, 3}}},
+    {{&grpc_static_metadata_refcounts[93], {{g_bytes + 1043, 3}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[93], {{g_bytes + 1018, 16}}},
+    {{&grpc_static_metadata_refcounts[94], {{g_bytes + 1046, 16}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
     {{&grpc_static_metadata_refcounts[7], {{g_bytes + 50, 11}}},
-     {&grpc_static_metadata_refcounts[94], {{g_bytes + 1034, 1}}}},
+     {&grpc_static_metadata_refcounts[95], {{g_bytes + 1062, 1}}}},
     {{&grpc_static_metadata_refcounts[7], {{g_bytes + 50, 11}}},
      {&grpc_static_metadata_refcounts[25], {{g_bytes + 350, 1}}}},
     {{&grpc_static_metadata_refcounts[7], {{g_bytes + 50, 11}}},
      {&grpc_static_metadata_refcounts[26], {{g_bytes + 351, 1}}}},
     {{&grpc_static_metadata_refcounts[9], {{g_bytes + 77, 13}}},
-     {&grpc_static_metadata_refcounts[95], {{g_bytes + 1035, 8}}}},
+     {&grpc_static_metadata_refcounts[96], {{g_bytes + 1063, 8}}}},
     {{&grpc_static_metadata_refcounts[9], {{g_bytes + 77, 13}}},
-     {&grpc_static_metadata_refcounts[36], {{g_bytes + 489, 4}}}},
+     {&grpc_static_metadata_refcounts[37], {{g_bytes + 517, 4}}}},
     {{&grpc_static_metadata_refcounts[9], {{g_bytes + 77, 13}}},
-     {&grpc_static_metadata_refcounts[35], {{g_bytes + 482, 7}}}},
+     {&grpc_static_metadata_refcounts[36], {{g_bytes + 510, 7}}}},
     {{&grpc_static_metadata_refcounts[5], {{g_bytes + 36, 2}}},
-     {&grpc_static_metadata_refcounts[96], {{g_bytes + 1043, 8}}}},
+     {&grpc_static_metadata_refcounts[97], {{g_bytes + 1071, 8}}}},
     {{&grpc_static_metadata_refcounts[14], {{g_bytes + 158, 12}}},
-     {&grpc_static_metadata_refcounts[97], {{g_bytes + 1051, 16}}}},
+     {&grpc_static_metadata_refcounts[98], {{g_bytes + 1079, 16}}}},
     {{&grpc_static_metadata_refcounts[4], {{g_bytes + 29, 7}}},
-     {&grpc_static_metadata_refcounts[98], {{g_bytes + 1067, 4}}}},
+     {&grpc_static_metadata_refcounts[99], {{g_bytes + 1095, 4}}}},
     {{&grpc_static_metadata_refcounts[1], {{g_bytes + 5, 7}}},
-     {&grpc_static_metadata_refcounts[99], {{g_bytes + 1071, 3}}}},
+     {&grpc_static_metadata_refcounts[100], {{g_bytes + 1099, 3}}}},
     {{&grpc_static_metadata_refcounts[16], {{g_bytes + 186, 15}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
     {{&grpc_static_metadata_refcounts[15], {{g_bytes + 170, 16}}},
-     {&grpc_static_metadata_refcounts[95], {{g_bytes + 1035, 8}}}},
+     {&grpc_static_metadata_refcounts[96], {{g_bytes + 1063, 8}}}},
     {{&grpc_static_metadata_refcounts[15], {{g_bytes + 170, 16}}},
-     {&grpc_static_metadata_refcounts[36], {{g_bytes + 489, 4}}}},
+     {&grpc_static_metadata_refcounts[37], {{g_bytes + 517, 4}}}},
     {{&grpc_static_metadata_refcounts[21], {{g_bytes + 282, 8}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
-    {{&grpc_static_metadata_refcounts[100], {{g_bytes + 1074, 11}}},
+    {{&grpc_static_metadata_refcounts[101], {{g_bytes + 1102, 11}}},
      {&grpc_static_metadata_refcounts[29], {{g_bytes + 354, 0}}}},
     {{&grpc_static_metadata_refcounts[10], {{g_bytes + 90, 20}}},
-     {&grpc_static_metadata_refcounts[95], {{g_bytes + 1035, 8}}}},
+     {&grpc_static_metadata_refcounts[96], {{g_bytes + 1063, 8}}}},
     {{&grpc_static_metadata_refcounts[10], {{g_bytes + 90, 20}}},
-     {&grpc_static_metadata_refcounts[35], {{g_bytes + 482, 7}}}},
+     {&grpc_static_metadata_refcounts[36], {{g_bytes + 510, 7}}}},
     {{&grpc_static_metadata_refcounts[10], {{g_bytes + 90, 20}}},
-     {&grpc_static_metadata_refcounts[101], {{g_bytes + 1085, 16}}}},
+     {&grpc_static_metadata_refcounts[102], {{g_bytes + 1113, 16}}}},
     {{&grpc_static_metadata_refcounts[10], {{g_bytes + 90, 20}}},
-     {&grpc_static_metadata_refcounts[36], {{g_bytes + 489, 4}}}},
+     {&grpc_static_metadata_refcounts[37], {{g_bytes + 517, 4}}}},
     {{&grpc_static_metadata_refcounts[10], {{g_bytes + 90, 20}}},
-     {&grpc_static_metadata_refcounts[102], {{g_bytes + 1101, 13}}}},
+     {&grpc_static_metadata_refcounts[103], {{g_bytes + 1129, 13}}}},
     {{&grpc_static_metadata_refcounts[10], {{g_bytes + 90, 20}}},
-     {&grpc_static_metadata_refcounts[103], {{g_bytes + 1114, 12}}}},
+     {&grpc_static_metadata_refcounts[104], {{g_bytes + 1142, 12}}}},
     {{&grpc_static_metadata_refcounts[10], {{g_bytes + 90, 20}}},
-     {&grpc_static_metadata_refcounts[104], {{g_bytes + 1126, 21}}}},
+     {&grpc_static_metadata_refcounts[105], {{g_bytes + 1154, 21}}}},
     {{&grpc_static_metadata_refcounts[16], {{g_bytes + 186, 15}}},
-     {&grpc_static_metadata_refcounts[95], {{g_bytes + 1035, 8}}}},
+     {&grpc_static_metadata_refcounts[96], {{g_bytes + 1063, 8}}}},
     {{&grpc_static_metadata_refcounts[16], {{g_bytes + 186, 15}}},
-     {&grpc_static_metadata_refcounts[36], {{g_bytes + 489, 4}}}},
+     {&grpc_static_metadata_refcounts[37], {{g_bytes + 517, 4}}}},
     {{&grpc_static_metadata_refcounts[16], {{g_bytes + 186, 15}}},
-     {&grpc_static_metadata_refcounts[102], {{g_bytes + 1101, 13}}}},
+     {&grpc_static_metadata_refcounts[103], {{g_bytes + 1129, 13}}}},
 };
 const uint8_t grpc_static_accept_encoding_metadata[8] = {0,  76, 77, 78,
                                                          79, 80, 81, 82};
diff --git a/src/core/lib/transport/static_metadata.h b/src/core/lib/transport/static_metadata.h
index 5e57ea5741..2bb9f72838 100644
--- a/src/core/lib/transport/static_metadata.h
+++ b/src/core/lib/transport/static_metadata.h
@@ -31,7 +31,7 @@
 
 #include "src/core/lib/transport/metadata.h"
 
-#define GRPC_STATIC_MDSTR_COUNT 105
+#define GRPC_STATIC_MDSTR_COUNT 106
 extern const grpc_slice grpc_static_slice_table[GRPC_STATIC_MDSTR_COUNT];
 /* ":path" */
 #define GRPC_MDSTR_PATH (grpc_static_slice_table[0])
@@ -107,147 +107,150 @@ extern const grpc_slice grpc_static_slice_table[GRPC_STATIC_MDSTR_COUNT];
 /* "/grpc.lb.v1.LoadBalancer/BalanceLoad" */
 #define GRPC_MDSTR_SLASH_GRPC_DOT_LB_DOT_V1_DOT_LOADBALANCER_SLASH_BALANCELOAD \
   (grpc_static_slice_table[34])
+/* "/grpc.health.v1.Health/Watch" */
+#define GRPC_MDSTR_SLASH_GRPC_DOT_HEALTH_DOT_V1_DOT_HEALTH_SLASH_WATCH \
+  (grpc_static_slice_table[35])
 /* "deflate" */
-#define GRPC_MDSTR_DEFLATE (grpc_static_slice_table[35])
+#define GRPC_MDSTR_DEFLATE (grpc_static_slice_table[36])
 /* "gzip" */
-#define GRPC_MDSTR_GZIP (grpc_static_slice_table[36])
+#define GRPC_MDSTR_GZIP (grpc_static_slice_table[37])
 /* "stream/gzip" */
-#define GRPC_MDSTR_STREAM_SLASH_GZIP (grpc_static_slice_table[37])
+#define GRPC_MDSTR_STREAM_SLASH_GZIP (grpc_static_slice_table[38])
 /* "GET" */
-#define GRPC_MDSTR_GET (grpc_static_slice_table[38])
+#define GRPC_MDSTR_GET (grpc_static_slice_table[39])
 /* "POST" */
-#define GRPC_MDSTR_POST (grpc_static_slice_table[39])
+#define GRPC_MDSTR_POST (grpc_static_slice_table[40])
 /* "/" */
-#define GRPC_MDSTR_SLASH (grpc_static_slice_table[40])
+#define GRPC_MDSTR_SLASH (grpc_static_slice_table[41])
 /* "/index.html" */
-#define GRPC_MDSTR_SLASH_INDEX_DOT_HTML (grpc_static_slice_table[41])
+#define GRPC_MDSTR_SLASH_INDEX_DOT_HTML (grpc_static_slice_table[42])
 /* "http" */
-#define GRPC_MDSTR_HTTP (grpc_static_slice_table[42])
+#define GRPC_MDSTR_HTTP (grpc_static_slice_table[43])
 /* "https" */
-#define GRPC_MDSTR_HTTPS (grpc_static_slice_table[43])
+#define GRPC_MDSTR_HTTPS (grpc_static_slice_table[44])
 /* "200" */
-#define GRPC_MDSTR_200 (grpc_static_slice_table[44])
+#define GRPC_MDSTR_200 (grpc_static_slice_table[45])
 /* "204" */
-#define GRPC_MDSTR_204 (grpc_static_slice_table[45])
+#define GRPC_MDSTR_204 (grpc_static_slice_table[46])
 /* "206" */
-#define GRPC_MDSTR_206 (grpc_static_slice_table[46])
+#define GRPC_MDSTR_206 (grpc_static_slice_table[47])
 /* "304" */
-#define GRPC_MDSTR_304 (grpc_static_slice_table[47])
+#define GRPC_MDSTR_304 (grpc_static_slice_table[48])
 /* "400" */
-#define GRPC_MDSTR_400 (grpc_static_slice_table[48])
+#define GRPC_MDSTR_400 (grpc_static_slice_table[49])
 /* "404" */
-#define GRPC_MDSTR_404 (grpc_static_slice_table[49])
+#define GRPC_MDSTR_404 (grpc_static_slice_table[50])
 /* "500" */
-#define GRPC_MDSTR_500 (grpc_static_slice_table[50])
+#define GRPC_MDSTR_500 (grpc_static_slice_table[51])
 /* "accept-charset" */
-#define GRPC_MDSTR_ACCEPT_CHARSET (grpc_static_slice_table[51])
+#define GRPC_MDSTR_ACCEPT_CHARSET (grpc_static_slice_table[52])
 /* "gzip, deflate" */
-#define GRPC_MDSTR_GZIP_COMMA_DEFLATE (grpc_static_slice_table[52])
+#define GRPC_MDSTR_GZIP_COMMA_DEFLATE (grpc_static_slice_table[53])
 /* "accept-language" */
-#define GRPC_MDSTR_ACCEPT_LANGUAGE (grpc_static_slice_table[53])
+#define GRPC_MDSTR_ACCEPT_LANGUAGE (grpc_static_slice_table[54])
 /* "accept-ranges" */
-#define GRPC_MDSTR_ACCEPT_RANGES (grpc_static_slice_table[54])
+#define GRPC_MDSTR_ACCEPT_RANGES (grpc_static_slice_table[55])
 /* "accept" */
-#define GRPC_MDSTR_ACCEPT (grpc_static_slice_table[55])
+#define GRPC_MDSTR_ACCEPT (grpc_static_slice_table[56])
 /* "access-control-allow-origin" */
-#define GRPC_MDSTR_ACCESS_CONTROL_ALLOW_ORIGIN (grpc_static_slice_table[56])
+#define GRPC_MDSTR_ACCESS_CONTROL_ALLOW_ORIGIN (grpc_static_slice_table[57])
 /* "age" */
-#define GRPC_MDSTR_AGE (grpc_static_slice_table[57])
+#define GRPC_MDSTR_AGE (grpc_static_slice_table[58])
 /* "allow" */
-#define GRPC_MDSTR_ALLOW (grpc_static_slice_table[58])
+#define GRPC_MDSTR_ALLOW (grpc_static_slice_table[59])
 /* "authorization" */
-#define GRPC_MDSTR_AUTHORIZATION (grpc_static_slice_table[59])
+#define GRPC_MDSTR_AUTHORIZATION (grpc_static_slice_table[60])
 /* "cache-control" */
-#define GRPC_MDSTR_CACHE_CONTROL (grpc_static_slice_table[60])
+#define GRPC_MDSTR_CACHE_CONTROL (grpc_static_slice_table[61])
 /* "content-disposition" */
-#define GRPC_MDSTR_CONTENT_DISPOSITION (grpc_static_slice_table[61])
+#define GRPC_MDSTR_CONTENT_DISPOSITION (grpc_static_slice_table[62])
 /* "content-language" */
-#define GRPC_MDSTR_CONTENT_LANGUAGE (grpc_static_slice_table[62])
+#define GRPC_MDSTR_CONTENT_LANGUAGE (grpc_static_slice_table[63])
 /* "content-length" */
-#define GRPC_MDSTR_CONTENT_LENGTH (grpc_static_slice_table[63])
+#define GRPC_MDSTR_CONTENT_LENGTH (grpc_static_slice_table[64])
 /* "content-location" */
-#define GRPC_MDSTR_CONTENT_LOCATION (grpc_static_slice_table[64])
+#define GRPC_MDSTR_CONTENT_LOCATION (grpc_static_slice_table[65])
 /* "content-range" */
-#define GRPC_MDSTR_CONTENT_RANGE (grpc_static_slice_table[65])
+#define GRPC_MDSTR_CONTENT_RANGE (grpc_static_slice_table[66])
 /* "cookie" */
-#define GRPC_MDSTR_COOKIE (grpc_static_slice_table[66])
+#define GRPC_MDSTR_COOKIE (grpc_static_slice_table[67])
 /* "date" */
-#define GRPC_MDSTR_DATE (grpc_static_slice_table[67])
+#define GRPC_MDSTR_DATE (grpc_static_slice_table[68])
 /* "etag" */
-#define GRPC_MDSTR_ETAG (grpc_static_slice_table[68])
+#define GRPC_MDSTR_ETAG (grpc_static_slice_table[69])
 /* "expect" */
-#define GRPC_MDSTR_EXPECT (grpc_static_slice_table[69])
+#define GRPC_MDSTR_EXPECT (grpc_static_slice_table[70])
 /* "expires" */
-#define GRPC_MDSTR_EXPIRES (grpc_static_slice_table[70])
+#define GRPC_MDSTR_EXPIRES (grpc_static_slice_table[71])
 /* "from" */
-#define GRPC_MDSTR_FROM (grpc_static_slice_table[71])
+#define GRPC_MDSTR_FROM (grpc_static_slice_table[72])
 /* "if-match" */
-#define GRPC_MDSTR_IF_MATCH (grpc_static_slice_table[72])
+#define GRPC_MDSTR_IF_MATCH (grpc_static_slice_table[73])
 /* "if-modified-since" */
-#define GRPC_MDSTR_IF_MODIFIED_SINCE (grpc_static_slice_table[73])
+#define GRPC_MDSTR_IF_MODIFIED_SINCE (grpc_static_slice_table[74])
 /* "if-none-match" */
-#define GRPC_MDSTR_IF_NONE_MATCH (grpc_static_slice_table[74])
+#define GRPC_MDSTR_IF_NONE_MATCH (grpc_static_slice_table[75])
 /* "if-range" */
-#define GRPC_MDSTR_IF_RANGE (grpc_static_slice_table[75])
+#define GRPC_MDSTR_IF_RANGE (grpc_static_slice_table[76])
 /* "if-unmodified-since" */
-#define GRPC_MDSTR_IF_UNMODIFIED_SINCE (grpc_static_slice_table[76])
+#define GRPC_MDSTR_IF_UNMODIFIED_SINCE (grpc_static_slice_table[77])
 /* "last-modified" */
-#define GRPC_MDSTR_LAST_MODIFIED (grpc_static_slice_table[77])
+#define GRPC_MDSTR_LAST_MODIFIED (grpc_static_slice_table[78])
 /* "link" */
-#define GRPC_MDSTR_LINK (grpc_static_slice_table[78])
+#define GRPC_MDSTR_LINK (grpc_static_slice_table[79])
 /* "location" */
-#define GRPC_MDSTR_LOCATION (grpc_static_slice_table[79])
+#define GRPC_MDSTR_LOCATION (grpc_static_slice_table[80])
 /* "max-forwards" */
-#define GRPC_MDSTR_MAX_FORWARDS (grpc_static_slice_table[80])
+#define GRPC_MDSTR_MAX_FORWARDS (grpc_static_slice_table[81])
 /* "proxy-authenticate" */
-#define GRPC_MDSTR_PROXY_AUTHENTICATE (grpc_static_slice_table[81])
+#define GRPC_MDSTR_PROXY_AUTHENTICATE (grpc_static_slice_table[82])
 /* "proxy-authorization" */
-#define GRPC_MDSTR_PROXY_AUTHORIZATION (grpc_static_slice_table[82])
+#define GRPC_MDSTR_PROXY_AUTHORIZATION (grpc_static_slice_table[83])
 /* "range" */
-#define GRPC_MDSTR_RANGE (grpc_static_slice_table[83])
+#define GRPC_MDSTR_RANGE (grpc_static_slice_table[84])
 /* "referer" */
-#define GRPC_MDSTR_REFERER (grpc_static_slice_table[84])
+#define GRPC_MDSTR_REFERER (grpc_static_slice_table[85])
 /* "refresh" */
-#define GRPC_MDSTR_REFRESH (grpc_static_slice_table[85])
+#define GRPC_MDSTR_REFRESH (grpc_static_slice_table[86])
 /* "retry-after" */
-#define GRPC_MDSTR_RETRY_AFTER (grpc_static_slice_table[86])
+#define GRPC_MDSTR_RETRY_AFTER (grpc_static_slice_table[87])
 /* "server" */
-#define GRPC_MDSTR_SERVER (grpc_static_slice_table[87])
+#define GRPC_MDSTR_SERVER (grpc_static_slice_table[88])
 /* "set-cookie" */
-#define GRPC_MDSTR_SET_COOKIE (grpc_static_slice_table[88])
+#define GRPC_MDSTR_SET_COOKIE (grpc_static_slice_table[89])
 /* "strict-transport-security" */
-#define GRPC_MDSTR_STRICT_TRANSPORT_SECURITY (grpc_static_slice_table[89])
+#define GRPC_MDSTR_STRICT_TRANSPORT_SECURITY (grpc_static_slice_table[90])
 /* "transfer-encoding" */
-#define GRPC_MDSTR_TRANSFER_ENCODING (grpc_static_slice_table[90])
+#define GRPC_MDSTR_TRANSFER_ENCODING (grpc_static_slice_table[91])
 /* "vary" */
-#define GRPC_MDSTR_VARY (grpc_static_slice_table[91])
+#define GRPC_MDSTR_VARY (grpc_static_slice_table[92])
 /* "via" */
-#define GRPC_MDSTR_VIA (grpc_static_slice_table[92])
+#define GRPC_MDSTR_VIA (grpc_static_slice_table[93])
 /* "www-authenticate" */
-#define GRPC_MDSTR_WWW_AUTHENTICATE (grpc_static_slice_table[93])
+#define GRPC_MDSTR_WWW_AUTHENTICATE (grpc_static_slice_table[94])
 /* "0" */
-#define GRPC_MDSTR_0 (grpc_static_slice_table[94])
+#define GRPC_MDSTR_0 (grpc_static_slice_table[95])
 /* "identity" */
-#define GRPC_MDSTR_IDENTITY (grpc_static_slice_table[95])
+#define GRPC_MDSTR_IDENTITY (grpc_static_slice_table[96])
 /* "trailers" */
-#define GRPC_MDSTR_TRAILERS (grpc_static_slice_table[96])
+#define GRPC_MDSTR_TRAILERS (grpc_static_slice_table[97])
 /* "application/grpc" */
-#define GRPC_MDSTR_APPLICATION_SLASH_GRPC (grpc_static_slice_table[97])
+#define GRPC_MDSTR_APPLICATION_SLASH_GRPC (grpc_static_slice_table[98])
 /* "grpc" */
-#define GRPC_MDSTR_GRPC (grpc_static_slice_table[98])
+#define GRPC_MDSTR_GRPC (grpc_static_slice_table[99])
 /* "PUT" */
-#define GRPC_MDSTR_PUT (grpc_static_slice_table[99])
+#define GRPC_MDSTR_PUT (grpc_static_slice_table[100])
 /* "lb-cost-bin" */
-#define GRPC_MDSTR_LB_COST_BIN (grpc_static_slice_table[100])
+#define GRPC_MDSTR_LB_COST_BIN (grpc_static_slice_table[101])
 /* "identity,deflate" */
-#define GRPC_MDSTR_IDENTITY_COMMA_DEFLATE (grpc_static_slice_table[101])
+#define GRPC_MDSTR_IDENTITY_COMMA_DEFLATE (grpc_static_slice_table[102])
 /* "identity,gzip" */
-#define GRPC_MDSTR_IDENTITY_COMMA_GZIP (grpc_static_slice_table[102])
+#define GRPC_MDSTR_IDENTITY_COMMA_GZIP (grpc_static_slice_table[103])
 /* "deflate,gzip" */
-#define GRPC_MDSTR_DEFLATE_COMMA_GZIP (grpc_static_slice_table[103])
+#define GRPC_MDSTR_DEFLATE_COMMA_GZIP (grpc_static_slice_table[104])
 /* "identity,deflate,gzip" */
 #define GRPC_MDSTR_IDENTITY_COMMA_DEFLATE_COMMA_GZIP \
-  (grpc_static_slice_table[104])
+  (grpc_static_slice_table[105])
 
 extern const grpc_slice_refcount_vtable grpc_static_metadata_vtable;
 extern grpc_slice_refcount
diff --git a/src/cpp/server/health/default_health_check_service.cc b/src/cpp/server/health/default_health_check_service.cc
index 0c03fdf17a..c951c69d51 100644
--- a/src/cpp/server/health/default_health_check_service.cc
+++ b/src/cpp/server/health/default_health_check_service.cc
@@ -26,8 +26,8 @@
 
 #include "pb_decode.h"
 #include "pb_encode.h"
+#include "src/core/ext/filters/client_channel/health/health.pb.h"
 #include "src/cpp/server/health/default_health_check_service.h"
-#include "src/cpp/server/health/health.pb.h"
 
 namespace grpc {
 
@@ -78,12 +78,12 @@ void DefaultHealthCheckService::RegisterCallHandler(
 
 void DefaultHealthCheckService::UnregisterCallHandler(
     const grpc::string& service_name,
-    std::shared_ptr<HealthCheckServiceImpl::CallHandler> handler) {
+    const std::shared_ptr<HealthCheckServiceImpl::CallHandler>& handler) {
   std::unique_lock<std::mutex> lock(mu_);
   auto it = services_map_.find(service_name);
   if (it == services_map_.end()) return;
   ServiceData& service_data = it->second;
-  service_data.RemoveCallHandler(std::move(handler));
+  service_data.RemoveCallHandler(handler);
   if (service_data.Unused()) {
     services_map_.erase(it);
   }
@@ -115,7 +115,7 @@ void DefaultHealthCheckService::ServiceData::AddCallHandler(
 }
 
 void DefaultHealthCheckService::ServiceData::RemoveCallHandler(
-    std::shared_ptr<HealthCheckServiceImpl::CallHandler> handler) {
+    const std::shared_ptr<HealthCheckServiceImpl::CallHandler>& handler) {
   call_handlers_.erase(handler);
 }
 
@@ -184,16 +184,13 @@ bool DefaultHealthCheckService::HealthCheckServiceImpl::DecodeRequest(
   std::vector<Slice> slices;
   if (!request.Dump(&slices).ok()) return false;
   uint8_t* request_bytes = nullptr;
-  bool request_bytes_owned = false;
   size_t request_size = 0;
   grpc_health_v1_HealthCheckRequest request_struct;
-  if (slices.empty()) {
-    request_struct.has_service = false;
-  } else if (slices.size() == 1) {
+  request_struct.has_service = false;
+  if (slices.size() == 1) {
     request_bytes = const_cast<uint8_t*>(slices[0].begin());
     request_size = slices[0].size();
-  } else {
-    request_bytes_owned = true;
+  } else if (slices.size() > 1) {
     request_bytes = static_cast<uint8_t*>(gpr_malloc(request.Length()));
     uint8_t* copy_to = request_bytes;
     for (size_t i = 0; i < slices.size(); i++) {
@@ -201,15 +198,13 @@ bool DefaultHealthCheckService::HealthCheckServiceImpl::DecodeRequest(
       copy_to += slices[i].size();
     }
   }
-  if (request_bytes != nullptr) {
-    pb_istream_t istream = pb_istream_from_buffer(request_bytes, request_size);
-    bool decode_status = pb_decode(
-        &istream, grpc_health_v1_HealthCheckRequest_fields, &request_struct);
-    if (request_bytes_owned) {
-      gpr_free(request_bytes);
-    }
-    if (!decode_status) return false;
+  pb_istream_t istream = pb_istream_from_buffer(request_bytes, request_size);
+  bool decode_status = pb_decode(
+      &istream, grpc_health_v1_HealthCheckRequest_fields, &request_struct);
+  if (slices.size() > 1) {
+    gpr_free(request_bytes);
   }
+  if (!decode_status) return false;
   *service_name = request_struct.has_service ? request_struct.service : "";
   return true;
 }
@@ -318,6 +313,7 @@ void DefaultHealthCheckService::HealthCheckServiceImpl::CheckCallHandler::
     gpr_log(GPR_DEBUG, "[HCS %p] Health check call finished for handler %p",
             service_, this);
   }
+  self.reset();  // To appease clang-tidy.
 }
 
 //
@@ -442,7 +438,7 @@ void DefaultHealthCheckService::HealthCheckServiceImpl::WatchCallHandler::
     SendFinish(std::shared_ptr<CallHandler> self, const Status& status) {
   if (finish_called_) return;
   std::unique_lock<std::mutex> cq_lock(service_->cq_shutdown_mu_);
-  if (!service_->shutdown_) return;
+  if (service_->shutdown_) return;
   SendFinishLocked(std::move(self), status);
 }
 
@@ -464,6 +460,7 @@ void DefaultHealthCheckService::HealthCheckServiceImpl::WatchCallHandler::
             "handler: %p).",
             service_, service_name_.c_str(), this);
   }
+  self.reset();  // To appease clang-tidy.
 }
 
 // TODO(roth): This method currently assumes that there will be only one
@@ -473,9 +470,10 @@ void DefaultHealthCheckService::HealthCheckServiceImpl::WatchCallHandler::
     OnDoneNotified(std::shared_ptr<CallHandler> self, bool ok) {
   GPR_ASSERT(ok);
   gpr_log(GPR_DEBUG,
-          "[HCS %p] Healt watch call is notified done (handler: %p, "
+          "[HCS %p] Health watch call is notified done (handler: %p, "
           "is_cancelled: %d).",
           service_, this, static_cast<int>(ctx_.IsCancelled()));
+  database_->UnregisterCallHandler(service_name_, self);
   SendFinish(std::move(self), Status::CANCELLED);
 }
 
diff --git a/src/cpp/server/health/default_health_check_service.h b/src/cpp/server/health/default_health_check_service.h
index 3bab76b6b0..450bd543f5 100644
--- a/src/cpp/server/health/default_health_check_service.h
+++ b/src/cpp/server/health/default_health_check_service.h
@@ -252,7 +252,7 @@ class DefaultHealthCheckService final : public HealthCheckServiceInterface {
     void AddCallHandler(
         std::shared_ptr<HealthCheckServiceImpl::CallHandler> handler);
     void RemoveCallHandler(
-        std::shared_ptr<HealthCheckServiceImpl::CallHandler> handler);
+        const std::shared_ptr<HealthCheckServiceImpl::CallHandler>& handler);
     bool Unused() const {
       return call_handlers_.empty() && status_ == NOT_FOUND;
     }
@@ -269,7 +269,7 @@ class DefaultHealthCheckService final : public HealthCheckServiceInterface {
 
   void UnregisterCallHandler(
       const grpc::string& service_name,
-      std::shared_ptr<HealthCheckServiceImpl::CallHandler> handler);
+      const std::shared_ptr<HealthCheckServiceImpl::CallHandler>& handler);
 
   mutable std::mutex mu_;
   std::map<grpc::string, ServiceData> services_map_;  // Guarded by mu_.
diff --git a/src/python/grpcio/grpc_core_dependencies.py b/src/python/grpcio/grpc_core_dependencies.py
index 0382c38fb9..cb48b9f62c 100644
--- a/src/python/grpcio/grpc_core_dependencies.py
+++ b/src/python/grpcio/grpc_core_dependencies.py
@@ -316,6 +316,7 @@ CORE_SOURCE_FILES = [
     'src/core/ext/filters/client_channel/client_channel_factory.cc',
     'src/core/ext/filters/client_channel/client_channel_plugin.cc',
     'src/core/ext/filters/client_channel/connector.cc',
+    'src/core/ext/filters/client_channel/health/health_check_client.cc',
     'src/core/ext/filters/client_channel/http_connect_handshaker.cc',
     'src/core/ext/filters/client_channel/http_proxy.cc',
     'src/core/ext/filters/client_channel/lb_policy.cc',
@@ -332,6 +333,7 @@ CORE_SOURCE_FILES = [
     'src/core/ext/filters/client_channel/subchannel_index.cc',
     'src/core/ext/filters/client_channel/uri_parser.cc',
     'src/core/ext/filters/deadline/deadline_filter.cc',
+    'src/core/ext/filters/client_channel/health/health.pb.c',
     'src/core/tsi/alts_transport_security.cc',
     'src/core/tsi/fake_transport_security.cc',
     'src/core/tsi/local_transport_security.cc',
diff --git a/test/core/end2end/fuzzers/hpack.dictionary b/test/core/end2end/fuzzers/hpack.dictionary
index 569e744a6b..a79fe5ad95 100644
--- a/test/core/end2end/fuzzers/hpack.dictionary
+++ b/test/core/end2end/fuzzers/hpack.dictionary
@@ -34,6 +34,7 @@
 "\x1Egrpc.max_request_message_bytes"
 "\x1Fgrpc.max_response_message_bytes"
 "$/grpc.lb.v1.LoadBalancer/BalanceLoad"
+"\x1C/grpc.health.v1.Health/Watch"
 "\x07deflate"
 "\x04gzip"
 "\x0Bstream/gzip"
diff --git a/test/cpp/end2end/client_lb_end2end_test.cc b/test/cpp/end2end/client_lb_end2end_test.cc
index 2110da84ee..28bc580cd4 100644
--- a/test/cpp/end2end/client_lb_end2end_test.cc
+++ b/test/cpp/end2end/client_lb_end2end_test.cc
@@ -31,6 +31,7 @@
 #include <grpcpp/channel.h>
 #include <grpcpp/client_context.h>
 #include <grpcpp/create_channel.h>
+#include <grpcpp/health_check_service_interface.h>
 #include <grpcpp/server.h>
 #include <grpcpp/server_builder.h>
 
@@ -289,6 +290,10 @@ class ClientLbEnd2endTest : public ::testing::Test {
       server_->Shutdown(grpc_timeout_milliseconds_to_deadline(0));
       if (join) thread_->join();
     }
+
+    void SetServingStatus(const grpc::string& service, bool serving) {
+      server_->GetHealthCheckService()->SetServingStatus(service, serving);
+    }
   };
 
   void ResetCounters() {
@@ -320,6 +325,17 @@ class ClientLbEnd2endTest : public ::testing::Test {
     return true;
   }
 
+  bool WaitForChannelReady(Channel* channel, int timeout_seconds = 5) {
+    const gpr_timespec deadline =
+        grpc_timeout_seconds_to_deadline(timeout_seconds);
+    grpc_connectivity_state state;
+    while ((state = channel->GetState(true /* try_to_connect */)) !=
+           GRPC_CHANNEL_READY) {
+      if (!channel->WaitForStateChange(state, deadline)) return false;
+    }
+    return true;
+  }
+
   bool SeenAllServers() {
     for (const auto& server : servers_) {
       if (server->service_.request_count() == 0) return false;
@@ -359,11 +375,7 @@ TEST_F(ClientLbEnd2endTest, PickFirst) {
   StartServers(kNumServers);
   auto channel = BuildChannel("");  // test that pick first is the default.
   auto stub = BuildStub(channel);
-  std::vector<int> ports;
-  for (size_t i = 0; i < servers_.size(); ++i) {
-    ports.emplace_back(servers_[i]->port_);
-  }
-  SetNextResolution(ports);
+  SetNextResolution(GetServersPorts());
   for (size_t i = 0; i < servers_.size(); ++i) {
     CheckRpcSendOk(stub, DEBUG_LOCATION);
   }
@@ -586,10 +598,7 @@ TEST_P(ClientLbEnd2endWithParamTest, PickFirstManyUpdates) {
   StartServers(kNumServers);
   auto channel = BuildChannel("pick_first");
   auto stub = BuildStub(channel);
-  std::vector<int> ports;
-  for (size_t i = 0; i < servers_.size(); ++i) {
-    ports.emplace_back(servers_[i]->port_);
-  }
+  std::vector<int> ports = GetServersPorts();
   for (size_t i = 0; i < 1000; ++i) {
     std::shuffle(ports.begin(), ports.end(),
                  std::mt19937(std::random_device()()));
@@ -719,11 +728,7 @@ TEST_F(ClientLbEnd2endTest, RoundRobin) {
   StartServers(kNumServers);
   auto channel = BuildChannel("round_robin");
   auto stub = BuildStub(channel);
-  std::vector<int> ports;
-  for (const auto& server : servers_) {
-    ports.emplace_back(server->port_);
-  }
-  SetNextResolution(ports);
+  SetNextResolution(GetServersPorts());
   // Wait until all backends are ready.
   do {
     CheckRpcSendOk(stub, DEBUG_LOCATION);
@@ -885,10 +890,7 @@ TEST_F(ClientLbEnd2endTest, RoundRobinManyUpdates) {
   StartServers(kNumServers);
   auto channel = BuildChannel("round_robin");
   auto stub = BuildStub(channel);
-  std::vector<int> ports;
-  for (size_t i = 0; i < servers_.size(); ++i) {
-    ports.emplace_back(servers_[i]->port_);
-  }
+  std::vector<int> ports = GetServersPorts();
   for (size_t i = 0; i < 1000; ++i) {
     std::shuffle(ports.begin(), ports.end(),
                  std::mt19937(std::random_device()()));
@@ -998,6 +1000,125 @@ TEST_F(ClientLbEnd2endTest, RoundRobinSingleReconnect) {
   WaitForServer(stub, 0, DEBUG_LOCATION);
 }
 
+// If health checking is required by client but health checking service
+// is not running on the server, the channel should be treated as healthy.
+TEST_F(ClientLbEnd2endTest,
+       RoundRobinServersHealthCheckingUnimplementedTreatedAsHealthy) {
+  StartServers(1);  // Single server
+  ChannelArguments args;
+  args.SetServiceConfigJSON(
+      "{\"healthCheckConfig\": "
+      "{\"serviceName\": \"health_check_service_name\"}}");
+  auto channel = BuildChannel("round_robin", args);
+  auto stub = BuildStub(channel);
+  SetNextResolution({servers_[0]->port_});
+  EXPECT_TRUE(WaitForChannelReady(channel.get()));
+  CheckRpcSendOk(stub, DEBUG_LOCATION);
+}
+
+TEST_F(ClientLbEnd2endTest, RoundRobinWithHealthChecking) {
+  EnableDefaultHealthCheckService(true);
+  // Start servers.
+  const int kNumServers = 3;
+  StartServers(kNumServers);
+  ChannelArguments args;
+  args.SetServiceConfigJSON(
+      "{\"healthCheckConfig\": "
+      "{\"serviceName\": \"health_check_service_name\"}}");
+  auto channel = BuildChannel("round_robin", args);
+  auto stub = BuildStub(channel);
+  SetNextResolution(GetServersPorts());
+  // Channel should not become READY, because health checks should be failing.
+  gpr_log(GPR_INFO,
+          "*** initial state: unknown health check service name for "
+          "all servers");
+  EXPECT_FALSE(WaitForChannelReady(channel.get(), 1));
+  // Now set one of the servers to be healthy.
+  // The channel should become healthy and all requests should go to
+  // the healthy server.
+  gpr_log(GPR_INFO, "*** server 0 healthy");
+  servers_[0]->SetServingStatus("health_check_service_name", true);
+  EXPECT_TRUE(WaitForChannelReady(channel.get()));
+  for (int i = 0; i < 10; ++i) {
+    CheckRpcSendOk(stub, DEBUG_LOCATION);
+  }
+  EXPECT_EQ(10, servers_[0]->service_.request_count());
+  EXPECT_EQ(0, servers_[1]->service_.request_count());
+  EXPECT_EQ(0, servers_[2]->service_.request_count());
+  // Now set a second server to be healthy.
+  gpr_log(GPR_INFO, "*** server 2 healthy");
+  servers_[2]->SetServingStatus("health_check_service_name", true);
+  WaitForServer(stub, 2, DEBUG_LOCATION);
+  for (int i = 0; i < 10; ++i) {
+    CheckRpcSendOk(stub, DEBUG_LOCATION);
+  }
+  EXPECT_EQ(5, servers_[0]->service_.request_count());
+  EXPECT_EQ(0, servers_[1]->service_.request_count());
+  EXPECT_EQ(5, servers_[2]->service_.request_count());
+  // Now set the remaining server to be healthy.
+  gpr_log(GPR_INFO, "*** server 1 healthy");
+  servers_[1]->SetServingStatus("health_check_service_name", true);
+  WaitForServer(stub, 1, DEBUG_LOCATION);
+  for (int i = 0; i < 9; ++i) {
+    CheckRpcSendOk(stub, DEBUG_LOCATION);
+  }
+  EXPECT_EQ(3, servers_[0]->service_.request_count());
+  EXPECT_EQ(3, servers_[1]->service_.request_count());
+  EXPECT_EQ(3, servers_[2]->service_.request_count());
+  // Now set one server to be unhealthy again.  Then wait until the
+  // unhealthiness has hit the client.  We know that the client will see
+  // this when we send kNumServers requests and one of the remaining servers
+  // sees two of the requests.
+  gpr_log(GPR_INFO, "*** server 0 unhealthy");
+  servers_[0]->SetServingStatus("health_check_service_name", false);
+  do {
+    ResetCounters();
+    for (int i = 0; i < kNumServers; ++i) {
+      CheckRpcSendOk(stub, DEBUG_LOCATION);
+    }
+  } while (servers_[1]->service_.request_count() != 2 &&
+           servers_[2]->service_.request_count() != 2);
+  // Now set the remaining two servers to be unhealthy.  Make sure the
+  // channel leaves READY state and that RPCs fail.
+  gpr_log(GPR_INFO, "*** all servers unhealthy");
+  servers_[1]->SetServingStatus("health_check_service_name", false);
+  servers_[2]->SetServingStatus("health_check_service_name", false);
+  EXPECT_TRUE(WaitForChannelNotReady(channel.get()));
+  CheckRpcSendFailure(stub);
+  // Clean up.
+  EnableDefaultHealthCheckService(false);
+}
+
+TEST_F(ClientLbEnd2endTest, RoundRobinWithHealthCheckingInhibitPerChannel) {
+  EnableDefaultHealthCheckService(true);
+  // Start server.
+  const int kNumServers = 1;
+  StartServers(kNumServers);
+  // Create a channel with health-checking enabled.
+  ChannelArguments args;
+  args.SetServiceConfigJSON(
+      "{\"healthCheckConfig\": "
+      "{\"serviceName\": \"health_check_service_name\"}}");
+  auto channel1 = BuildChannel("round_robin", args);
+  auto stub1 = BuildStub(channel1);
+  std::vector<int> ports = GetServersPorts();
+  SetNextResolution(ports);
+  // Create a channel with health checking enabled but inhibited.
+  args.SetInt(GRPC_ARG_INHIBIT_HEALTH_CHECKING, 1);
+  auto channel2 = BuildChannel("round_robin", args);
+  auto stub2 = BuildStub(channel2);
+  SetNextResolution(ports);
+  // First channel should not become READY, because health checks should be
+  // failing.
+  EXPECT_FALSE(WaitForChannelReady(channel1.get(), 1));
+  CheckRpcSendFailure(stub1);
+  // Second channel should be READY.
+  EXPECT_TRUE(WaitForChannelReady(channel2.get(), 1));
+  CheckRpcSendOk(stub2, DEBUG_LOCATION);
+  // Clean up.
+  EnableDefaultHealthCheckService(false);
+}
+
 }  // namespace
 }  // namespace testing
 }  // namespace grpc
diff --git a/tools/codegen/core/gen_static_metadata.py b/tools/codegen/core/gen_static_metadata.py
index f705a9bd41..adfd4a24f9 100755
--- a/tools/codegen/core/gen_static_metadata.py
+++ b/tools/codegen/core/gen_static_metadata.py
@@ -63,6 +63,7 @@ CONFIG = [
     'grpc.max_response_message_bytes',
     # well known method names
     '/grpc.lb.v1.LoadBalancer/BalanceLoad',
+    '/grpc.health.v1.Health/Watch',
     # compression algorithm names
     'deflate',
     'gzip',
diff --git a/tools/distrib/check_copyright.py b/tools/distrib/check_copyright.py
index 77f602ad1f..787bef1778 100755
--- a/tools/distrib/check_copyright.py
+++ b/tools/distrib/check_copyright.py
@@ -75,6 +75,8 @@ _EXEMPT = frozenset((
     'examples/python/multiplex/route_guide_pb2_grpc.py',
     'examples/python/route_guide/route_guide_pb2.py',
     'examples/python/route_guide/route_guide_pb2_grpc.py',
+    'src/core/ext/filters/client_channel/health/health.pb.h',
+    'src/core/ext/filters/client_channel/health/health.pb.c',
     'src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.h',
     'src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.c',
     'src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/google/protobuf/duration.pb.h',
@@ -87,8 +89,6 @@ _EXEMPT = frozenset((
     'src/core/tsi/alts/handshaker/handshaker.pb.c',
     'src/core/tsi/alts/handshaker/transport_security_common.pb.h',
     'src/core/tsi/alts/handshaker/transport_security_common.pb.c',
-    'src/cpp/server/health/health.pb.h',
-    'src/cpp/server/health/health.pb.c',
 
     # An older file originally from outside gRPC.
     'src/php/tests/bootstrap.php',
diff --git a/tools/distrib/check_include_guards.py b/tools/distrib/check_include_guards.py
index 56f48af56a..b8d530cce0 100755
--- a/tools/distrib/check_include_guards.py
+++ b/tools/distrib/check_include_guards.py
@@ -156,6 +156,7 @@ argp.add_argument('--precommit', default=False, action='store_true')
 args = argp.parse_args()
 
 KNOWN_BAD = set([
+    'src/core/ext/filters/client_channel/health/health.pb.h',
     'src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/load_balancer.pb.h',
     'src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/google/protobuf/duration.pb.h',
     'src/core/ext/filters/client_channel/lb_policy/grpclb/proto/grpc/lb/v1/google/protobuf/timestamp.pb.h',
diff --git a/tools/distrib/check_nanopb_output.sh b/tools/distrib/check_nanopb_output.sh
index 1c2ef9b768..018cbb7b66 100755
--- a/tools/distrib/check_nanopb_output.sh
+++ b/tools/distrib/check_nanopb_output.sh
@@ -71,7 +71,7 @@ fi
 #
 # checks for health.proto
 #
-readonly HEALTH_GRPC_OUTPUT_PATH='src/cpp/server/health'
+readonly HEALTH_GRPC_OUTPUT_PATH='src/core/ext/filters/client_channel/health'
 # nanopb-compile the proto to a temp location
 ./tools/codegen/core/gen_nano_proto.sh \
   src/proto/grpc/health/v1/health.proto \
@@ -79,7 +79,7 @@ readonly HEALTH_GRPC_OUTPUT_PATH='src/cpp/server/health'
   "$HEALTH_GRPC_OUTPUT_PATH"
 # compare outputs to checked compiled code
 for NANOPB_OUTPUT_FILE in $NANOPB_HEALTH_TMP_OUTPUT/*.pb.*; do
-  if ! diff "$NANOPB_OUTPUT_FILE" "src/cpp/server/health/$(basename $NANOPB_OUTPUT_FILE)"; then
+  if ! diff "$NANOPB_OUTPUT_FILE" "${HEALTH_GRPC_OUTPUT_PATH}/$(basename $NANOPB_OUTPUT_FILE)"; then
     echo "Outputs differ: $NANOPB_HEALTH_TMP_OUTPUT vs $HEALTH_GRPC_OUTPUT_PATH"
     exit 2
   fi
diff --git a/tools/doxygen/Doxyfile.c++.internal b/tools/doxygen/Doxyfile.c++.internal
index 790d756680..26e671668e 100644
--- a/tools/doxygen/Doxyfile.c++.internal
+++ b/tools/doxygen/Doxyfile.c++.internal
@@ -1012,6 +1012,8 @@ include/grpcpp/support/string_ref.h \
 include/grpcpp/support/stub_options.h \
 include/grpcpp/support/sync_stream.h \
 include/grpcpp/support/time.h \
+src/core/ext/filters/client_channel/health/health.pb.c \
+src/core/ext/filters/client_channel/health/health.pb.h \
 src/core/ext/transport/inproc/inproc_transport.h \
 src/core/lib/avl/avl.h \
 src/core/lib/backoff/backoff.h \
@@ -1208,8 +1210,6 @@ src/cpp/server/dynamic_thread_pool.cc \
 src/cpp/server/dynamic_thread_pool.h \
 src/cpp/server/health/default_health_check_service.cc \
 src/cpp/server/health/default_health_check_service.h \
-src/cpp/server/health/health.pb.c \
-src/cpp/server/health/health.pb.h \
 src/cpp/server/health/health_check_service.cc \
 src/cpp/server/health/health_check_service_server_builder_option.cc \
 src/cpp/server/insecure_server_credentials.cc \
@@ -1228,8 +1228,11 @@ src/cpp/util/status.cc \
 src/cpp/util/string_ref.cc \
 src/cpp/util/time_cc.cc \
 third_party/nanopb/pb.h \
+third_party/nanopb/pb_common.c \
 third_party/nanopb/pb_common.h \
+third_party/nanopb/pb_decode.c \
 third_party/nanopb/pb_decode.h \
+third_party/nanopb/pb_encode.c \
 third_party/nanopb/pb_encode.h
 
 # This tag can be used to specify the character encoding of the source files
diff --git a/tools/doxygen/Doxyfile.core.internal b/tools/doxygen/Doxyfile.core.internal
index 8ab7b6ea4a..437253c01b 100644
--- a/tools/doxygen/Doxyfile.core.internal
+++ b/tools/doxygen/Doxyfile.core.internal
@@ -885,6 +885,10 @@ src/core/ext/filters/client_channel/client_channel_factory.h \
 src/core/ext/filters/client_channel/client_channel_plugin.cc \
 src/core/ext/filters/client_channel/connector.cc \
 src/core/ext/filters/client_channel/connector.h \
+src/core/ext/filters/client_channel/health/health.pb.c \
+src/core/ext/filters/client_channel/health/health.pb.h \
+src/core/ext/filters/client_channel/health/health_check_client.cc \
+src/core/ext/filters/client_channel/health/health_check_client.h \
 src/core/ext/filters/client_channel/http_connect_handshaker.cc \
 src/core/ext/filters/client_channel/http_connect_handshaker.h \
 src/core/ext/filters/client_channel/http_proxy.cc \
diff --git a/tools/run_tests/generated/sources_and_headers.json b/tools/run_tests/generated/sources_and_headers.json
index 4e1f26a0e5..3a442864e8 100644
--- a/tools/run_tests/generated/sources_and_headers.json
+++ b/tools/run_tests/generated/sources_and_headers.json
@@ -9966,7 +9966,8 @@
     "deps": [
       "gpr", 
       "grpc_base", 
-      "grpc_deadline_filter"
+      "grpc_deadline_filter", 
+      "health_proto"
     ], 
     "headers": [
       "src/core/ext/filters/client_channel/backup_poller.h", 
@@ -9974,6 +9975,7 @@
       "src/core/ext/filters/client_channel/client_channel_channelz.h", 
       "src/core/ext/filters/client_channel/client_channel_factory.h", 
       "src/core/ext/filters/client_channel/connector.h", 
+      "src/core/ext/filters/client_channel/health/health_check_client.h", 
       "src/core/ext/filters/client_channel/http_connect_handshaker.h", 
       "src/core/ext/filters/client_channel/http_proxy.h", 
       "src/core/ext/filters/client_channel/lb_policy.h", 
@@ -10007,6 +10009,8 @@
       "src/core/ext/filters/client_channel/client_channel_plugin.cc", 
       "src/core/ext/filters/client_channel/connector.cc", 
       "src/core/ext/filters/client_channel/connector.h", 
+      "src/core/ext/filters/client_channel/health/health_check_client.cc", 
+      "src/core/ext/filters/client_channel/health/health_check_client.h", 
       "src/core/ext/filters/client_channel/http_connect_handshaker.cc", 
       "src/core/ext/filters/client_channel/http_connect_handshaker.h", 
       "src/core/ext/filters/client_channel/http_proxy.cc", 
@@ -10988,6 +10992,23 @@
   }, 
   {
     "deps": [
+      "nanopb"
+    ], 
+    "headers": [
+      "src/core/ext/filters/client_channel/health/health.pb.h"
+    ], 
+    "is_filegroup": true, 
+    "language": "c", 
+    "name": "health_proto", 
+    "src": [
+      "src/core/ext/filters/client_channel/health/health.pb.c", 
+      "src/core/ext/filters/client_channel/health/health.pb.h"
+    ], 
+    "third_party": false, 
+    "type": "filegroup"
+  }, 
+  {
+    "deps": [
       "nanopb_headers"
     ], 
     "headers": [], 
@@ -11280,6 +11301,7 @@
       "grpc++_codegen_base", 
       "grpc_base_headers", 
       "grpc_transport_inproc_headers", 
+      "health_proto", 
       "nanopb_headers"
     ], 
     "headers": [
@@ -11380,7 +11402,6 @@
       "src/cpp/common/channel_filter.h", 
       "src/cpp/server/dynamic_thread_pool.h", 
       "src/cpp/server/health/default_health_check_service.h", 
-      "src/cpp/server/health/health.pb.h", 
       "src/cpp/server/thread_pool_interface.h", 
       "src/cpp/thread_manager/thread_manager.h"
     ], 
@@ -11505,8 +11526,6 @@
       "src/cpp/server/dynamic_thread_pool.h", 
       "src/cpp/server/health/default_health_check_service.cc", 
       "src/cpp/server/health/default_health_check_service.h", 
-      "src/cpp/server/health/health.pb.c", 
-      "src/cpp/server/health/health.pb.h", 
       "src/cpp/server/health/health_check_service.cc", 
       "src/cpp/server/health/health_check_service_server_builder_option.cc", 
       "src/cpp/server/server_builder.cc",