Merge pull request #107512 from SataQiu/support-reset-dryrun-20220113

kubeadm reset: add support for dry-run

cmd/kubeadm/app/cmd/phases/reset/cleanupnode.go

@@ -63,40 +63,55 @@ func runCleanupNode(c workflow.RunData) error {
 		klog.Warningln("[reset] The kubelet service could not be stopped by kubeadm. Unable to detect a supported init system!")
 		klog.Warningln("[reset] Please ensure kubelet is stopped manually")
 	} else {
-		fmt.Println("[reset] Stopping the kubelet service")
+		if !r.DryRun() {
-		if err := initSystem.ServiceStop("kubelet"); err != nil {
+			fmt.Println("[reset] Stopping the kubelet service")
-			klog.Warningf("[reset] The kubelet service could not be stopped by kubeadm: [%v]\n", err)
+			if err := initSystem.ServiceStop("kubelet"); err != nil {
-			klog.Warningln("[reset] Please ensure kubelet is stopped manually")
+				klog.Warningf("[reset] The kubelet service could not be stopped by kubeadm: [%v]\n", err)
+				klog.Warningln("[reset] Please ensure kubelet is stopped manually")
+			}
+		} else {
+			fmt.Println("[reset] Would stop the kubelet service")
 		}
 	}
 
-	// Try to unmount mounted directories under kubeadmconstants.KubeletRunDirectory in order to be able to remove the kubeadmconstants.KubeletRunDirectory directory later
+	if !r.DryRun() {
-	fmt.Printf("[reset] Unmounting mounted directories in %q\n", kubeadmconstants.KubeletRunDirectory)
+		// Try to unmount mounted directories under kubeadmconstants.KubeletRunDirectory in order to be able to remove the kubeadmconstants.KubeletRunDirectory directory later
-	// In case KubeletRunDirectory holds a symbolic link, evaluate it
+		fmt.Printf("[reset] Unmounting mounted directories in %q\n", kubeadmconstants.KubeletRunDirectory)
-	kubeletRunDir, err := absoluteKubeletRunDirectory()
+		// In case KubeletRunDirectory holds a symbolic link, evaluate it
-	if err == nil {
+		kubeletRunDir, err := absoluteKubeletRunDirectory()
-		// Only clean absoluteKubeletRunDirectory if umountDirsCmd passed without error
+		if err == nil {
-		r.AddDirsToClean(kubeletRunDir)
+			// Only clean absoluteKubeletRunDirectory if umountDirsCmd passed without error
+			r.AddDirsToClean(kubeletRunDir)
+		}
+	} else {
+		fmt.Printf("[reset] Would unmount mounted directories in %q\n", kubeadmconstants.KubeletRunDirectory)
 	}
 
-	klog.V(1).Info("[reset] Removing Kubernetes-managed containers")
+	if !r.DryRun() {
-	if err := removeContainers(utilsexec.New(), r.CRISocketPath()); err != nil {
+		klog.V(1).Info("[reset] Removing Kubernetes-managed containers")
-		klog.Warningf("[reset] Failed to remove containers: %v\n", err)
+		if err := removeContainers(utilsexec.New(), r.CRISocketPath()); err != nil {
+			klog.Warningf("[reset] Failed to remove containers: %v\n", err)
+		}
+	} else {
+		fmt.Println("[reset] Would remove Kubernetes-managed containers")
 	}
 
 	r.AddDirsToClean("/var/lib/dockershim", "/var/run/kubernetes", "/var/lib/cni")
 
 	// Remove contents from the config and pki directories
-	klog.V(1).Infoln("[reset] Removing contents from the config and pki directories")
 	if certsDir != kubeadmapiv1.DefaultCertificatesDir {
 		klog.Warningf("[reset] WARNING: Cleaning a non-default certificates directory: %q\n", certsDir)
 	}
-	resetConfigDir(kubeadmconstants.KubernetesDir, certsDir)
+	resetConfigDir(kubeadmconstants.KubernetesDir, certsDir, r.DryRun())
 
 	if r.Cfg() != nil && features.Enabled(r.Cfg().FeatureGates, features.RootlessControlPlane) {
-		klog.V(1).Infoln("[reset] Removing users and groups created for rootless control-plane")
+		if !r.DryRun() {
-		if err := users.RemoveUsersAndGroups(); err != nil {
+			klog.V(1).Infoln("[reset] Removing users and groups created for rootless control-plane")
-			klog.Warningf("[reset] Failed to remove users and groups: %v\n", err)
+			if err := users.RemoveUsersAndGroups(); err != nil {
+				klog.Warningf("[reset] Failed to remove users and groups: %v\n", err)
+			}
+		} else {
+			fmt.Println("[reset] Would remove users and groups created for rootless control-plane")
 		}
 	}
 
@@ -130,16 +145,20 @@ func removeContainers(execer utilsexec.Interface, criSocketPath string) error {
 }
 
 // resetConfigDir is used to cleanup the files kubeadm writes in /etc/kubernetes/.
-func resetConfigDir(configPathDir, pkiPathDir string) {
+func resetConfigDir(configPathDir, pkiPathDir string, isDryRun bool) {
 	dirsToClean := []string{
 		filepath.Join(configPathDir, kubeadmconstants.ManifestsSubDirName),
 		pkiPathDir,
 	}
-	fmt.Printf("[reset] Deleting contents of config directories: %v\n", dirsToClean)
+	if !isDryRun {
-	for _, dir := range dirsToClean {
+		fmt.Printf("[reset] Deleting contents of directories: %v\n", dirsToClean)
-		if err := CleanDir(dir); err != nil {
+		for _, dir := range dirsToClean {
-			klog.Warningf("[reset] Failed to delete contents of %q directory: %v", dir, err)
+			if err := CleanDir(dir); err != nil {
+				klog.Warningf("[reset] Failed to delete contents of %q directory: %v", dir, err)
+			}
 		}
+	} else {
+		fmt.Printf("[reset] Would delete contents of directories: %v\n", dirsToClean)
 	}
 
 	filesToClean := []string{
@@ -149,11 +168,16 @@ func resetConfigDir(configPathDir, pkiPathDir string) {
 		filepath.Join(configPathDir, kubeadmconstants.ControllerManagerKubeConfigFileName),
 		filepath.Join(configPathDir, kubeadmconstants.SchedulerKubeConfigFileName),
 	}
-	fmt.Printf("[reset] Deleting files: %v\n", filesToClean)
+
-	for _, path := range filesToClean {
+	if !isDryRun {
-		if err := os.RemoveAll(path); err != nil {
+		fmt.Printf("[reset] Deleting files: %v\n", filesToClean)
-			klog.Warningf("[reset] Failed to remove file: %q [%v]\n", path, err)
+		for _, path := range filesToClean {
+			if err := os.RemoveAll(path); err != nil {
+				klog.Warningf("[reset] Failed to remove file: %q [%v]\n", path, err)
+			}
 		}
+	} else {
+		fmt.Printf("[reset] Would delete files: %v\n", filesToClean)
 	}
 }
 

cmd/kubeadm/app/cmd/phases/reset/cleanupnode_test.go

@@ -174,7 +174,7 @@ func TestConfigDirCleaner(t *testing.T) {
 			if test.resetDir == "" {
 				test.resetDir = "pki"
 			}
-			resetConfigDir(tmpDir, filepath.Join(tmpDir, test.resetDir))
+			resetConfigDir(tmpDir, filepath.Join(tmpDir, test.resetDir), false)
 
 			// Verify the files we cleanup implicitly in every test:
 			assertExists(t, tmpDir)

cmd/kubeadm/app/cmd/phases/reset/data.go

@@ -32,6 +32,7 @@ type resetData interface {
 	InputReader() io.Reader
 	IgnorePreflightErrors() sets.String
 	Cfg() *kubeadmapi.InitConfiguration
+	DryRun() bool
 	Client() clientset.Interface
 	AddDirsToClean(dirs ...string)
 	CertificatesDir() string

cmd/kubeadm/app/cmd/phases/reset/removeetcdmember.go

@@ -58,8 +58,12 @@ func runRemoveETCDMemberPhase(c workflow.RunData) error {
 	if err == nil {
 		r.AddDirsToClean(etcdDataDir)
 		if cfg != nil {
-			if err := etcdphase.RemoveStackedEtcdMemberFromCluster(r.Client(), cfg); err != nil {
+			if !r.DryRun() {
-				klog.Warningf("[reset] failed to remove etcd member: %v, please manually remove this etcd member using etcdctl", err)
+				if err := etcdphase.RemoveStackedEtcdMemberFromCluster(r.Client(), cfg); err != nil {
+					klog.Warningf("[reset] Failed to remove etcd member: %v, please manually remove this etcd member using etcdctl", err)
+				}
+			} else {
+				fmt.Println("[reset] Would remove the etcd member on this node from the etcd cluster")
 			}
 		}
 	} else {

cmd/kubeadm/app/cmd/reset.go

@@ -64,6 +64,7 @@ type resetOptions struct {
 	forceReset            bool
 	ignorePreflightErrors []string
 	kubeconfigPath        string
+	dryRun                bool
 }
 
 // resetData defines all the runtime information used when running the kubeadm reset workflow;
@@ -78,6 +79,7 @@ type resetData struct {
 	outputWriter          io.Writer
 	cfg                   *kubeadmapi.InitConfiguration
 	dirsToClean           []string
+	dryRun                bool
 }
 
 // newResetOptions returns a struct ready for being used for creating cmd join flags.
@@ -134,6 +136,7 @@ func newResetData(cmd *cobra.Command, options *resetOptions, in io.Reader, out i
 		inputReader:           in,
 		outputWriter:          out,
 		cfg:                   cfg,
+		dryRun:                options.dryRun,
 	}, nil
 }
 
@@ -154,6 +157,10 @@ func AddResetFlags(flagSet *flag.FlagSet, resetOptions *resetOptions) {
 		&resetOptions.forceReset, options.ForceReset, "f", false,
 		"Reset the node without prompting for confirmation.",
 	)
+	flagSet.BoolVar(
+		&resetOptions.dryRun, options.DryRun, resetOptions.dryRun,
+		"Don't apply any changes; just output what would be done.",
+	)
 
 	options.AddKubeConfigFlag(flagSet, &resetOptions.kubeconfigPath)
 	options.AddIgnorePreflightErrorsFlag(flagSet, &resetOptions.ignorePreflightErrors)
@@ -214,6 +221,11 @@ func newCmdReset(in io.Reader, out io.Writer, resetOptions *resetOptions) *cobra
 }
 
 func cleanDirs(data *resetData) {
+	if data.DryRun() {
+		fmt.Printf("[reset] Would delete contents of stateful directories: %v\n", data.dirsToClean)
+		return
+	}
+
 	fmt.Printf("[reset] Deleting contents of stateful directories: %v\n", data.dirsToClean)
 	for _, dir := range data.dirsToClean {
 		klog.V(1).Infof("[reset] Deleting contents of %s", dir)
@@ -228,6 +240,11 @@ func (r *resetData) Cfg() *kubeadmapi.InitConfiguration {
 	return r.cfg
 }
 
+// DryRun returns the DryRun flag.
+func (r *resetData) DryRun() bool {
+	return r.dryRun
+}
+
 // CertificatesDir returns the CertificatesDir.
 func (r *resetData) CertificatesDir() string {
 	return r.certificatesDir