kube-proxy: use netutils.MultiListen for healthz and metrics server

Signed-off-by: Daman Arora <aroradaman@gmail.com>
(cherry picked from commit 7ce36f9bca)

cmd/kube-proxy/app/server.go

@@ -419,7 +419,7 @@ func serveHealthz(ctx context.Context, hz *healthcheck.ProxierHealthServer, errC
 	}
 
 	fn := func() {
-		err := hz.Run()
+		err := hz.Run(ctx)
 		if err != nil {
 			logger.Error(err, "Healthz server failed")
 			if errCh != nil {
@@ -435,7 +435,7 @@ func serveHealthz(ctx context.Context, hz *healthcheck.ProxierHealthServer, errC
 	go wait.Until(fn, 5*time.Second, ctx.Done())
 }
 
-func serveMetrics(bindAddress string, proxyMode kubeproxyconfig.ProxyMode, enableProfiling bool, errCh chan error) {
+func serveMetrics(ctx context.Context, bindAddress string, proxyMode kubeproxyconfig.ProxyMode, enableProfiling bool, errCh chan error) {
 	if len(bindAddress) == 0 {
 		return
 	}
@@ -460,17 +460,31 @@ func serveMetrics(bindAddress string, proxyMode kubeproxyconfig.ProxyMode, enabl
 	configz.InstallHandler(proxyMux)
 
 	fn := func() {
-		err := http.ListenAndServe(bindAddress, proxyMux)
-		if err != nil {
-			err = fmt.Errorf("starting metrics server failed: %w", err)
-			utilruntime.HandleError(err)
-			if errCh != nil {
-				errCh <- err
-				// if in hardfail mode, never retry again
-				blockCh := make(chan error)
-				<-blockCh
+		var err error
+		defer func() {
+			if err != nil {
+				err = fmt.Errorf("starting metrics server failed: %w", err)
+				utilruntime.HandleError(err)
+				if errCh != nil {
+					errCh <- err
+					// if in hardfail mode, never retry again
+					blockCh := make(chan error)
+					<-blockCh
+				}
 			}
+		}()
+
+		listener, err := netutils.MultiListen(ctx, "tcp", bindAddress)
+		if err != nil {
+			return
 		}
+
+		server := &http.Server{Handler: proxyMux}
+		err = server.Serve(listener)
+		if err != nil {
+			return
+		}
+
 	}
 	go wait.Until(fn, 5*time.Second, wait.NeverStop)
 }
@@ -512,7 +526,7 @@ func (s *ProxyServer) Run(ctx context.Context) error {
 	serveHealthz(ctx, s.HealthzServer, healthzErrCh)
 
 	// Start up a metrics server if requested
-	serveMetrics(s.Config.MetricsBindAddress, s.Config.Mode, s.Config.EnableProfiling, metricsErrCh)
+	serveMetrics(ctx, s.Config.MetricsBindAddress, s.Config.Mode, s.Config.EnableProfiling, metricsErrCh)
 
 	noProxyName, err := labels.NewRequirement(apis.LabelServiceProxyName, selection.DoesNotExist, nil)
 	if err != nil {

pkg/proxy/healthcheck/common.go

@@ -17,22 +17,25 @@ limitations under the License.
 package healthcheck
 
 import (
+	"context"
 	"net"
 	"net/http"
+
+	netutils "k8s.io/utils/net"
 )
 
 // listener allows for testing of ServiceHealthServer and ProxierHealthServer.
 type listener interface {
-	// Listen is very much like net.Listen, except the first arg (network) is
+	// Listen is very much like netutils.MultiListen, except the second arg (network) is
 	// fixed to be "tcp".
-	Listen(addr string) (net.Listener, error)
+	Listen(ctx context.Context, addrs ...string) (net.Listener, error)
 }
 
 // httpServerFactory allows for testing of ServiceHealthServer and ProxierHealthServer.
 type httpServerFactory interface {
 	// New creates an instance of a type satisfying HTTPServer.  This is
 	// designed to include http.Server.
-	New(addr string, handler http.Handler) httpServer
+	New(handler http.Handler) httpServer
 }
 
 // httpServer allows for testing of ServiceHealthServer and ProxierHealthServer.
@@ -45,8 +48,8 @@ type httpServer interface {
 // Implement listener in terms of net.Listen.
 type stdNetListener struct{}
 
-func (stdNetListener) Listen(addr string) (net.Listener, error) {
-	return net.Listen("tcp", addr)
+func (stdNetListener) Listen(ctx context.Context, addrs ...string) (net.Listener, error) {
+	return netutils.MultiListen(ctx, "tcp", addrs...)
 }
 
 var _ listener = stdNetListener{}
@@ -54,9 +57,8 @@ var _ listener = stdNetListener{}
 // Implement httpServerFactory in terms of http.Server.
 type stdHTTPServerFactory struct{}
 
-func (stdHTTPServerFactory) New(addr string, handler http.Handler) httpServer {
+func (stdHTTPServerFactory) New(handler http.Handler) httpServer {
 	return &http.Server{
-		Addr:    addr,
 		Handler: handler,
 	}
 }

pkg/proxy/healthcheck/healthcheck_test.go

@@ -17,6 +17,7 @@ limitations under the License.
 package healthcheck
 
 import (
+	"context"
 	"encoding/json"
 	"net"
 	"net/http"
@@ -54,17 +55,17 @@ func (fake *fakeListener) hasPort(addr string) bool {
 	return fake.openPorts.Has(addr)
 }
 
-func (fake *fakeListener) Listen(addr string) (net.Listener, error) {
-	fake.openPorts.Insert(addr)
+func (fake *fakeListener) Listen(_ context.Context, addrs ...string) (net.Listener, error) {
+	fake.openPorts.Insert(addrs...)
 	return &fakeNetListener{
 		parent: fake,
-		addr:   addr,
+		addrs:  addrs,
 	}, nil
 }
 
 type fakeNetListener struct {
 	parent *fakeListener
-	addr   string
+	addrs  []string
 }
 
 type fakeAddr struct {
@@ -82,7 +83,7 @@ func (fake *fakeNetListener) Accept() (net.Conn, error) {
 }
 
 func (fake *fakeNetListener) Close() error {
-	fake.parent.openPorts.Delete(fake.addr)
+	fake.parent.openPorts.Delete(fake.addrs...)
 	return nil
 }
 
@@ -97,15 +98,13 @@ func newFakeHTTPServerFactory() *fakeHTTPServerFactory {
 	return &fakeHTTPServerFactory{}
 }
 
-func (fake *fakeHTTPServerFactory) New(addr string, handler http.Handler) httpServer {
+func (fake *fakeHTTPServerFactory) New(handler http.Handler) httpServer {
 	return &fakeHTTPServer{
-		addr:    addr,
 		handler: handler,
 	}
 }
 
 type fakeHTTPServer struct {
-	addr    string
 	handler http.Handler
 }
 
@@ -471,7 +470,7 @@ func TestHealthzServer(t *testing.T) {
 	fakeClock := testingclock.NewFakeClock(time.Now())
 
 	hs := newProxierHealthServer(listener, httpFactory, fakeClock, "127.0.0.1:10256", 10*time.Second)
-	server := hs.httpFactory.New(hs.addr, healthzHandler{hs: hs})
+	server := hs.httpFactory.New(healthzHandler{hs: hs})
 
 	hsTest := &serverTest{
 		server:      server,
@@ -506,7 +505,7 @@ func TestLivezServer(t *testing.T) {
 	fakeClock := testingclock.NewFakeClock(time.Now())
 
 	hs := newProxierHealthServer(listener, httpFactory, fakeClock, "127.0.0.1:10256", 10*time.Second)
-	server := hs.httpFactory.New(hs.addr, livezHandler{hs: hs})
+	server := hs.httpFactory.New(livezHandler{hs: hs})
 
 	hsTest := &serverTest{
 		server:      server,

pkg/proxy/healthcheck/proxier_health.go

@@ -17,6 +17,7 @@ limitations under the License.
 package healthcheck
 
 import (
+	"context"
 	"fmt"
 	"net/http"
 	"sync"
@@ -162,13 +163,13 @@ func (hs *ProxierHealthServer) NodeEligible() bool {
 }
 
 // Run starts the healthz HTTP server and blocks until it exits.
-func (hs *ProxierHealthServer) Run() error {
+func (hs *ProxierHealthServer) Run(ctx context.Context) error {
 	serveMux := http.NewServeMux()
 	serveMux.Handle("/healthz", healthzHandler{hs: hs})
 	serveMux.Handle("/livez", livezHandler{hs: hs})
-	server := hs.httpFactory.New(hs.addr, serveMux)
+	server := hs.httpFactory.New(serveMux)
 
-	listener, err := hs.listener.Listen(hs.addr)
+	listener, err := hs.listener.Listen(ctx, hs.addr)
 	if err != nil {
 		return fmt.Errorf("failed to start proxier healthz on %s: %v", hs.addr, err)
 	}

pkg/proxy/healthcheck/service_health.go

@@ -17,6 +17,7 @@ limitations under the License.
 package healthcheck
 
 import (
+	"context"
 	"fmt"
 	"net"
 	"net/http"
@@ -170,9 +171,9 @@ func (hcI *hcInstance) listenAndServeAll(hcs *server) error {
 	for _, ip := range hcs.nodeIPs {
 		addr := net.JoinHostPort(ip.String(), fmt.Sprint(hcI.port))
 		// create http server
-		httpSrv := hcs.httpFactory.New(addr, hcHandler{name: hcI.nsn, hcs: hcs})
+		httpSrv := hcs.httpFactory.New(hcHandler{name: hcI.nsn, hcs: hcs})
 		// start listener
-		listener, err = hcs.listener.Listen(addr)
+		listener, err = hcs.listener.Listen(context.TODO(), addr)
 		if err != nil {
 			// must close whatever have been previously opened
 			// to allow a retry/or port ownership change as needed