Replace getLocalhostIP with Loopback helper method

pkg/cli/server/server.go

@@ -469,7 +469,7 @@ func run(app *cli.Context, cfg *cmds.Server, leaderControllers server.CustomCont
 		systemd.SdNotify(true, "READY=1\n")
 	}()
 
-	url := fmt.Sprintf("https://%s:%d", serverConfig.ControlConfig.BindAddressOrLoopback(false), serverConfig.ControlConfig.SupervisorPort)
+	url := fmt.Sprintf("https://%s:%d", serverConfig.ControlConfig.BindAddressOrLoopback(false, true), serverConfig.ControlConfig.SupervisorPort)
 	token, err := clientaccess.FormatToken(serverConfig.ControlConfig.Runtime.AgentToken, serverConfig.ControlConfig.Runtime.ServerCA)
 	if err != nil {
 		return err

pkg/daemons/config/types.go

@@ -215,32 +215,36 @@ type Control struct {
 	Runtime     *ControlRuntime `json:"-"`
 }
 
-// BindAddressOrLoopback returns an IPv4 or IPv6 address suitable for embedding in server
-// URLs. If a bind address was configured, that is returned. If the chooseHostInterface
-// parameter is true, and a suitable default interface can be found, that interface's
-// address is returned.  If neither of the previous were used, the loopback address is
-// returned. IPv6 addresses are enclosed in square brackets, as per RFC2732.
-func (c *Control) BindAddressOrLoopback(chooseHostInterface bool) string {
+// BindAddressOrLoopback returns an IPv4 or IPv6 address suitable for embedding in
+// server URLs. If a bind address was configured, that is returned. If the
+// chooseHostInterface parameter is true, and a suitable default interface can be
+// found, that interface's address is returned.  If neither of the previous were used,
+// the loopback address is returned. If the urlSafe parameter is true, IPv6 addresses
+// are enclosed in square brackets, as per RFC2732.
+func (c *Control) BindAddressOrLoopback(chooseHostInterface, urlSafe bool) string {
 	ip := c.BindAddress
 	if ip == "" && chooseHostInterface {
 		if hostIP, _ := utilnet.ChooseHostInterface(); len(hostIP) > 0 {
 			ip = hostIP.String()
 		}
 	}
-	if utilsnet.IsIPv6String(ip) {
+	if urlSafe && utilsnet.IsIPv6String(ip) {
 		return fmt.Sprintf("[%s]", ip)
 	} else if ip != "" {
 		return ip
 	}
-	return c.Loopback()
+	return c.Loopback(urlSafe)
 }
 
 // Loopback returns an IPv4 or IPv6 loopback address, depending on whether the cluster
-// service CIDRs indicate an IPv4/Dual-Stack or IPv6 only cluster.  IPv6 addresses are
-// enclosed in square brackets, as per RFC2732.
-func (c *Control) Loopback() string {
+// service CIDRs indicate an IPv4/Dual-Stack or IPv6 only cluster. If the urlSafe
+// parameter is true, IPv6 addresses are enclosed in square brackets, as per RFC2732.
+func (c *Control) Loopback(urlSafe bool) string {
 	if IPv6OnlyService, _ := util.IsIPv6OnlyCIDRs(c.ServiceIPRanges); IPv6OnlyService {
-		return "[::1]"
+		if urlSafe {
+			return "[::1]"
+		}
+		return "::1"
 	}
 	return "127.0.0.1"
 }

pkg/daemons/control/deps/deps.go

@@ -314,7 +314,7 @@ func genClientCerts(config *config.Control) error {
 
 	var certGen bool
 
-	apiEndpoint := fmt.Sprintf("https://%s:%d", config.Loopback(), config.APIServerPort)
+	apiEndpoint := fmt.Sprintf("https://%s:%d", config.Loopback(true), config.APIServerPort)
 
 	certGen, err = factory("system:admin", []string{user.SystemPrivilegedGroup}, runtime.ClientAdminCert, runtime.ClientAdminKey)
 	if err != nil {
@@ -734,7 +734,7 @@ func genEgressSelectorConfig(controlConfig *config.Control) error {
 			ProxyProtocol: apiserver.ProtocolHTTPConnect,
 			Transport: &apiserver.Transport{
 				TCP: &apiserver.TCPTransport{
-					URL: fmt.Sprintf("https://%s:%d", controlConfig.BindAddressOrLoopback(false), controlConfig.SupervisorPort),
+					URL: fmt.Sprintf("https://%s:%d", controlConfig.BindAddressOrLoopback(false, true), controlConfig.SupervisorPort),
 					TLSConfig: &apiserver.TLSConfig{
 						CABundle:   controlConfig.Runtime.ServerCA,
 						ClientKey:  controlConfig.Runtime.ClientKubeAPIKey,

pkg/daemons/control/server.go

@@ -31,14 +31,6 @@ import (
 	_ "k8s.io/component-base/metrics/prometheus/restclient"
 )
 
-func getLocalhostIP(serviceCIDR []*net.IPNet) net.IP {
-	IPv6OnlyService, _ := util.IsIPv6OnlyCIDRs(serviceCIDR)
-	if IPv6OnlyService {
-		return net.ParseIP("::1")
-	}
-	return net.ParseIP("127.0.0.1")
-}
-
 func Server(ctx context.Context, cfg *config.Control) error {
 	rand.Seed(time.Now().UTC().UnixNano())
 
@@ -111,7 +103,7 @@ func controllerManager(ctx context.Context, cfg *config.Control) error {
 		"cluster-cidr":                     util.JoinIPNets(cfg.ClusterIPRanges),
 		"root-ca-file":                     runtime.ServerCA,
 		"profiling":                        "false",
-		"bind-address":                     getLocalhostIP(cfg.ServiceIPRanges).String(),
+		"bind-address":                     cfg.Loopback(false),
 		"secure-port":                      "10257",
 		"use-service-account-credentials":  "true",
 		"cluster-signing-kube-apiserver-client-cert-file": runtime.ClientCA,
@@ -143,7 +135,7 @@ func scheduler(ctx context.Context, cfg *config.Control) error {
 		"kubeconfig":                runtime.KubeConfigScheduler,
 		"authorization-kubeconfig":  runtime.KubeConfigScheduler,
 		"authentication-kubeconfig": runtime.KubeConfigScheduler,
-		"bind-address":              getLocalhostIP(cfg.ServiceIPRanges).String(),
+		"bind-address":              cfg.Loopback(false),
 		"secure-port":               "10259",
 		"profiling":                 "false",
 	}
@@ -179,7 +171,7 @@ func apiServer(ctx context.Context, cfg *config.Control) error {
 	}
 	argsMap["secure-port"] = strconv.Itoa(cfg.APIServerPort)
 	if cfg.APIServerBindAddress == "" {
-		argsMap["bind-address"] = getLocalhostIP(cfg.ServiceIPRanges).String()
+		argsMap["bind-address"] = cfg.Loopback(false)
 	} else {
 		argsMap["bind-address"] = cfg.APIServerBindAddress
 	}
@@ -316,7 +308,7 @@ func cloudControllerManager(ctx context.Context, cfg *config.Control) error {
 		"authorization-kubeconfig":     runtime.KubeConfigCloudController,
 		"authentication-kubeconfig":    runtime.KubeConfigCloudController,
 		"node-status-update-frequency": "1m0s",
-		"bind-address":                 getLocalhostIP(cfg.ServiceIPRanges).String(),
+		"bind-address":                 cfg.Loopback(false),
 	}
 	if cfg.NoLeaderElect {
 		argsMap["leader-elect"] = "false"

pkg/daemons/control/tunnel.go

@@ -210,7 +210,7 @@ func (t *TunnelServer) dialBackend(ctx context.Context, addr string) (net.Conn,
 	if err != nil {
 		return nil, err
 	}
-	loopback := t.config.Loopback()
+	loopback := t.config.Loopback(true)
 
 	var nodeName string
 	var toKubelet, useTunnel bool

pkg/etcd/etcd.go

@@ -653,7 +653,7 @@ func getEndpoints(control *config.Control) []string {
 	if len(runtime.EtcdConfig.Endpoints) > 0 {
 		return runtime.EtcdConfig.Endpoints
 	}
-	return []string{fmt.Sprintf("https://%s:2379", control.Loopback())}
+	return []string{fmt.Sprintf("https://%s:2379", control.Loopback(true))}
 }
 
 // toTLSConfig converts the ControlRuntime configuration to TLS configuration suitable
@@ -769,7 +769,7 @@ func (e *ETCD) peerURL() string {
 // During cluster reset/restore, we only listen on loopback to avoid having peers
 // connect mid-process.
 func (e *ETCD) listenPeerURLs(reset bool) string {
-	peerURLs := fmt.Sprintf("https://%s:2380", e.config.Loopback())
+	peerURLs := fmt.Sprintf("https://%s:2380", e.config.Loopback(true))
 	if !reset {
 		peerURLs += "," + e.peerURL()
 	}
@@ -785,7 +785,7 @@ func (e *ETCD) clientURL() string {
 // During cluster reset/restore, we only listen on loopback to avoid having the apiserver
 // connect mid-process.
 func (e *ETCD) listenClientURLs(reset bool) string {
-	clientURLs := fmt.Sprintf("https://%s:2379", e.config.Loopback())
+	clientURLs := fmt.Sprintf("https://%s:2379", e.config.Loopback(true))
 	if !reset {
 		clientURLs += "," + e.clientURL()
 	}
@@ -794,7 +794,7 @@ func (e *ETCD) listenClientURLs(reset bool) string {
 
 // listenMetricsURLs returns a list of URLs to bind to for metrics connections.
 func (e *ETCD) listenMetricsURLs(reset bool) string {
-	metricsURLs := fmt.Sprintf("http://%s:2381", e.config.Loopback())
+	metricsURLs := fmt.Sprintf("http://%s:2381", e.config.Loopback(true))
 	if !reset && e.config.EtcdExposeMetrics {
 		metricsURLs += "," + fmt.Sprintf("http://%s", net.JoinHostPort(e.address, "2381"))
 	}

pkg/server/server.go

@@ -337,18 +337,18 @@ func printTokens(config *config.Control) error {
 	}
 
 	if len(nodeFile) > 0 {
-		printToken(config.SupervisorPort, config.BindAddressOrLoopback(true), "To join node to cluster:", "agent")
+		printToken(config.SupervisorPort, config.BindAddressOrLoopback(true, true), "To join node to cluster:", "agent")
 	}
 
 	return nil
 }
 
 func writeKubeConfig(certs string, config *Config) error {
-	ip := config.ControlConfig.BindAddressOrLoopback(false)
+	ip := config.ControlConfig.BindAddressOrLoopback(false, true)
 	port := config.ControlConfig.HTTPSPort
 	// on servers without a local apiserver, tunnel access via the loadbalancer
 	if config.ControlConfig.DisableAPIServer {
-		ip = config.ControlConfig.Loopback()
+		ip = config.ControlConfig.Loopback(true)
 		port = config.ControlConfig.APIServerPort
 	}
 	url := fmt.Sprintf("https://%s:%d", ip, port)