Add /healthz back to kube-proxy metrics server

cmd/kube-proxy/app/server.go

@@ -38,6 +38,7 @@ import (
 	utilnet "k8s.io/apimachinery/pkg/util/net"
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 	"k8s.io/apimachinery/pkg/util/wait"
+	"k8s.io/apiserver/pkg/server/healthz"
 	utilfeature "k8s.io/apiserver/pkg/util/feature"
 	clientgoclientset "k8s.io/client-go/kubernetes"
 	v1core "k8s.io/client-go/kubernetes/typed/core/v1"
@@ -630,6 +631,7 @@ func (s *ProxyServer) Run() error {
 	// Start up a metrics server if requested
 	if len(s.MetricsBindAddress) > 0 {
 		mux := http.NewServeMux()
+		healthz.InstallHandler(mux)
 		mux.HandleFunc("/proxyMode", func(w http.ResponseWriter, r *http.Request) {
 			fmt.Fprintf(w, "%s", s.ProxyMode)
 		})