Merge pull request #12706 from ptabor/20210218

clientv3: PS: Replace balancer with upstream grpc solution

server/etcdmain/grpc_proxy.go

@@ -208,7 +208,13 @@ func startGRPCProxy(cmd *cobra.Command, args []string) {
 	}()
 
 	client := mustNewClient(lg)
-	proxyClient := mustNewProxyClient(lg, tlsinfo)
+
+	// The proxy client is used for self-healthchecking.
+	// TODO: The mechanism should be refactored to use internal connection.
+	var proxyClient *clientv3.Client
+	if grpcProxyAdvertiseClientURL != "" {
+		proxyClient = mustNewProxyClient(lg, tlsinfo)
+	}
 	httpClient := mustNewHTTPClient(lg)
 
 	srvhttp, httpl := mustHTTPListener(lg, m, tlsinfo, client, proxyClient)

server/proxy/grpcproxy/health.go

@@ -56,6 +56,9 @@ func checkHealth(c *clientv3.Client) etcdhttp.Health {
 }
 
 func checkProxyHealth(c *clientv3.Client) etcdhttp.Health {
+	if c == nil {
+		return etcdhttp.Health{Health: "false", Reason: "no connection to proxy"}
+	}
 	h := checkHealth(c)
 	if h.Health != "true" {
 		return h