[kube-controller-manager] Lower timeout for leaderelection resourcelock

Migrate how resource lock and leader election config is generated to new way, hidding kubeClient. This also halfs kubeClient timeout, making it an useful value.

If timeout is equal to RenewDeadline and we hit client timeout on request, there will be no retry, as RenewDeadline part will cancel the context and lose leader election. So setting a timeout to value at least equal to RenewDeadline is pointless.

Setting it as half of RenewDeadline is a heuristic to resolve this missing retry problem without adding additional parameter.

cmd/kube-controller-manager/app/config/config.go

@@ -40,9 +40,6 @@ type Config struct {
 	// the general kube client
 	Client *clientset.Clientset
 
-	// the client only used for leader election
-	LeaderElectionClient *clientset.Clientset
-
 	// the rest config for the master
 	Kubeconfig *restclient.Config
 

cmd/kube-controller-manager/app/controllermanager.go

@@ -270,15 +270,15 @@ func Run(c *config.CompletedConfig, stopCh <-chan struct{}) error {
 	// add a uniquifier so that two processes on the same host don't accidentally both become active
 	id = id + "_" + string(uuid.NewUUID())
 
-	rl, err := resourcelock.New(c.ComponentConfig.Generic.LeaderElection.ResourceLock,
+	rl, err := resourcelock.NewFromKubeconfig(c.ComponentConfig.Generic.LeaderElection.ResourceLock,
 		c.ComponentConfig.Generic.LeaderElection.ResourceNamespace,
 		c.ComponentConfig.Generic.LeaderElection.ResourceName,
-		c.LeaderElectionClient.CoreV1(),
-		c.LeaderElectionClient.CoordinationV1(),
 		resourcelock.ResourceLockConfig{
 			Identity:      id,
 			EventRecorder: c.EventRecorder,
-		})
+		},
+		c.Kubeconfig,
+		c.ComponentConfig.Generic.LeaderElection.RenewDeadline.Duration)
 	if err != nil {
 		klog.Fatalf("error creating lock: %v", err)
 	}

cmd/kube-controller-manager/app/options/options.go

@@ -441,18 +441,12 @@ func (s KubeControllerManagerOptions) Config(allControllers []string, disabledBy
 		return nil, err
 	}
 
-	// shallow copy, do not modify the kubeconfig.Timeout.
-	config := *kubeconfig
-	config.Timeout = s.Generic.LeaderElection.RenewDeadline.Duration
-	leaderElectionClient := clientset.NewForConfigOrDie(restclient.AddUserAgent(&config, "leader-election"))
-
 	eventRecorder := createRecorder(client, KubeControllerManagerUserAgent)
 
 	c := &kubecontrollerconfig.Config{
-		Client:               client,
-		Kubeconfig:           kubeconfig,
-		EventRecorder:        eventRecorder,
-		LeaderElectionClient: leaderElectionClient,
+		Client:        client,
+		Kubeconfig:    kubeconfig,
+		EventRecorder: eventRecorder,
 	}
 	if err := s.ApplyTo(c); err != nil {
 		return nil, err