Merge pull request kubernetes#126336 from HirazawaUi/remove-runonce-mode

Kubelet: Remove runonce mode

Author: k8s-ci-robot

cmd/kubelet/app/server.go

@@ -901,7 +901,7 @@ func run(ctx context.Context, s *options.KubeletServer, kubeDeps *kubelet.Depend
 		klog.InfoS("Failed to ApplyOOMScoreAdj", "err", err)
 	}
 
-	if err := RunKubelet(ctx, s, kubeDeps, s.RunOnce); err != nil {
+	if err := RunKubelet(ctx, s, kubeDeps); err != nil {
 		return err
 	}
 
@@ -916,10 +916,6 @@ func run(ctx context.Context, s *options.KubeletServer, kubeDeps *kubelet.Depend
 		}, 5*time.Second, wait.NeverStop)
 	}
 
-	if s.RunOnce {
-		return nil
-	}
-
 	// If systemd is used, notify it that we have started
 	go daemon.SdNotify(false, "READY=1")
 
@@ -1232,7 +1228,7 @@ func setContentTypeForClient(cfg *restclient.Config, contentType string) {
 //	3 Standalone 'kubernetes' binary
 //
 // Eventually, #2 will be replaced with instances of #3
-func RunKubelet(ctx context.Context, kubeServer *options.KubeletServer, kubeDeps *kubelet.Dependencies, runOnce bool) error {
+func RunKubelet(ctx context.Context, kubeServer *options.KubeletServer, kubeDeps *kubelet.Dependencies) error {
 	hostname, err := nodeutil.GetHostname(kubeServer.HostnameOverride)
 	if err != nil {
 		return err
@@ -1286,16 +1282,9 @@ func RunKubelet(ctx context.Context, kubeServer *options.KubeletServer, kubeDeps
 		klog.ErrorS(err, "Failed to set rlimit on max file handles")
 	}
 
-	// process pods and exit.
-	if runOnce {
-		if _, err := k.RunOnce(podCfg.Updates()); err != nil {
-			return fmt.Errorf("runonce failed: %w", err)
-		}
-		klog.InfoS("Started kubelet as runonce")
-	} else {
-		startKubelet(k, podCfg, &kubeServer.KubeletConfiguration, kubeDeps, kubeServer.EnableServer)
-		klog.InfoS("Started kubelet")
-	}
+	startKubelet(k, podCfg, &kubeServer.KubeletConfiguration, kubeDeps, kubeServer.EnableServer)
+	klog.InfoS("Started kubelet")
+
 	return nil
 }
 

pkg/kubelet/apis/config/types.go

@@ -285,6 +285,7 @@ type KubeletConfiguration struct {
 	ResolverConfig string
 	// RunOnce causes the Kubelet to check the API server once for pods,
 	// run those in addition to the pods specified by static pod files, and exit.
+	// Deprecated: no longer has any effect.
 	RunOnce bool
 	// cpuCFSQuota enables CPU CFS quota enforcement for containers that
 	// specify CPU limits

pkg/kubelet/apis/config/validation/validation.go

@@ -140,6 +140,9 @@ func ValidateKubeletConfiguration(kc *kubeletconfig.KubeletConfiguration, featur
 	if kc.ServerTLSBootstrap && !localFeatureGate.Enabled(features.RotateKubeletServerCertificate) {
 		allErrors = append(allErrors, fmt.Errorf("invalid configuration: serverTLSBootstrap %v requires feature gate RotateKubeletServerCertificate", kc.ServerTLSBootstrap))
 	}
+	if kc.RunOnce {
+		allErrors = append(allErrors, fmt.Errorf("invalid configuration: runOnce (--runOnce) %v, Runonce mode has been deprecated and should not be set", kc.RunOnce))
+	}
 
 	for _, nodeTaint := range kc.RegisterWithTaints {
 		if err := utiltaints.CheckTaintValidation(nodeTaint); err != nil {

pkg/kubelet/kubelet.go

@@ -278,7 +278,6 @@ type Bootstrap interface {
 	ListenAndServeReadOnly(address net.IP, port uint, tp trace.TracerProvider)
 	ListenAndServePodResources()
 	Run(<-chan kubetypes.PodUpdate)
-	RunOnce(<-chan kubetypes.PodUpdate) ([]RunPodResult, error)
 }
 
 // Dependencies is a bin for things we might consider "injected dependencies" -- objects constructed