kubeadm: fix a bug where file copy(backup) could not be executed correctly on Windows platform during upgrade

cmd/kubeadm/app/cmd/phases/init/certs.go

@@ -27,11 +27,11 @@ import (
 	kubeadmscheme "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/scheme"
 	kubeadmapiv1 "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1beta3"
 	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/options"
-	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/phases"
 	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/phases/workflow"
 	cmdutil "k8s.io/kubernetes/cmd/kubeadm/app/cmd/util"
 	kubeadmconstants "k8s.io/kubernetes/cmd/kubeadm/app/constants"
 	certsphase "k8s.io/kubernetes/cmd/kubeadm/app/phases/certs"
+	kubeadmutil "k8s.io/kubernetes/cmd/kubeadm/app/util"
 	"k8s.io/kubernetes/cmd/kubeadm/app/util/pkiutil"
 )
 
@@ -219,7 +219,7 @@ func runCAPhase(ca *certsphase.KubeadmCert) func(c workflow.RunData) error {
 
 			// If CA Cert existed while dryrun, copy CA Cert to dryrun dir for later use
 			if data.DryRun() {
-				err := phases.CopyFile(filepath.Join(data.CertificateDir(), kubeadmconstants.CACertName), filepath.Join(data.CertificateWriteDir(), kubeadmconstants.CACertName))
+				err := kubeadmutil.CopyFile(filepath.Join(data.CertificateDir(), kubeadmconstants.CACertName), filepath.Join(data.CertificateWriteDir(), kubeadmconstants.CACertName))
 				if err != nil {
 					return errors.Wrapf(err, "could not copy %s to dry run directory %s", kubeadmconstants.CACertName, data.CertificateWriteDir())
 				}
@@ -227,7 +227,7 @@ func runCAPhase(ca *certsphase.KubeadmCert) func(c workflow.RunData) error {
 			if _, err := pkiutil.TryLoadKeyFromDisk(data.CertificateDir(), ca.BaseName); err == nil {
 				// If CA Key existed while dryrun, copy CA Key to dryrun dir for later use
 				if data.DryRun() {
-					err := phases.CopyFile(filepath.Join(data.CertificateDir(), kubeadmconstants.CAKeyName), filepath.Join(data.CertificateWriteDir(), kubeadmconstants.CAKeyName))
+					err := kubeadmutil.CopyFile(filepath.Join(data.CertificateDir(), kubeadmconstants.CAKeyName), filepath.Join(data.CertificateWriteDir(), kubeadmconstants.CAKeyName))
 					if err != nil {
 						return errors.Wrapf(err, "could not copy %s to dry run directory %s", kubeadmconstants.CAKeyName, data.CertificateWriteDir())
 					}

cmd/kubeadm/app/cmd/phases/init/kubeconfig.go

@@ -23,11 +23,11 @@ import (
 	"github.com/pkg/errors"
 
 	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/options"
-	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/phases"
 	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/phases/workflow"
 	cmdutil "k8s.io/kubernetes/cmd/kubeadm/app/cmd/util"
 	kubeadmconstants "k8s.io/kubernetes/cmd/kubeadm/app/constants"
 	kubeconfigphase "k8s.io/kubernetes/cmd/kubeadm/app/phases/kubeconfig"
+	kubeadmutil "k8s.io/kubernetes/cmd/kubeadm/app/util"
 )
 
 var (
@@ -138,7 +138,7 @@ func runKubeConfigFile(kubeConfigFileName string) func(workflow.RunData) error {
 			fmt.Printf("[kubeconfig] External CA mode: Using user provided %s\n", kubeConfigFileName)
 			// If using an external CA while dryrun, copy kubeconfig files to dryrun dir for later use
 			if data.DryRun() {
-				err := phases.CopyFile(filepath.Join(kubeadmconstants.KubernetesDir, kubeConfigFileName), filepath.Join(data.KubeConfigDir(), kubeConfigFileName))
+				err := kubeadmutil.CopyFile(filepath.Join(kubeadmconstants.KubernetesDir, kubeConfigFileName), filepath.Join(data.KubeConfigDir(), kubeConfigFileName))
 				if err != nil {
 					return errors.Wrapf(err, "could not copy %s to dry run directory %s", kubeConfigFileName, data.KubeConfigDir())
 				}

cmd/kubeadm/app/cmd/phases/util.go

@@ -17,8 +17,6 @@ limitations under the License.
 package phases
 
 import (
-	"os"
-
 	"k8s.io/component-base/version"
 
 	kubeadmapiv1 "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1beta3"
@@ -33,17 +31,3 @@ func SetKubernetesVersion(cfg *kubeadmapiv1.ClusterConfiguration) {
 	}
 	cfg.KubernetesVersion = version.Get().String()
 }
-
-// CopyFile copy file from src to dest.
-func CopyFile(src, dest string) error {
-	fileInfo, err := os.Stat(src)
-	if err != nil {
-		return err
-	}
-	contents, err := os.ReadFile(src)
-	if err != nil {
-		return err
-	}
-	err = os.WriteFile(dest, contents, fileInfo.Mode())
-	return err
-}

cmd/kubeadm/app/phases/upgrade/postupgrade.go

@@ -265,14 +265,10 @@ func WriteKubeletConfigFiles(cfg *kubeadmapi.InitConfiguration, patchesDir strin
 	dest := filepath.Join(backupDir, kubeadmconstants.KubeletConfigurationFileName)
 
 	if !dryRun {
-		// call `cp` instead of `rename` here since the kubelet config file and back up directory (/etc/kubernetes/tmp/)
-		// might on the filesystem with different mount points in the test environment, such as kinder.
-		// This will lead to a failure to move the file from the source to dest since `rename` normally doesn't work
-		// across different mount points on most Unix system.
 		fmt.Printf("[upgrade] Backing up kubelet config file to %s\n", dest)
-		output, err := kubeadmutil.CopyDir(src, dest)
+		err := kubeadmutil.CopyFile(src, dest)
 		if err != nil {
-			return errors.Wrapf(err, "error backing up the kubelet config file, output: %q", output)
+			return errors.Wrap(err, "error backing up the kubelet config file")
 		}
 	} else {
 		fmt.Printf("[dryrun] Would back up kubelet config file to %s\n", dest)

cmd/kubeadm/app/util/copy.go

@@ -0,0 +1,35 @@
+/*
+Copyright 2023 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package util
+
+import (
+	"os"
+)
+
+// CopyFile copies a file from src to dest.
+func CopyFile(src, dest string) error {
+	fileInfo, err := os.Stat(src)
+	if err != nil {
+		return err
+	}
+	contents, err := os.ReadFile(src)
+	if err != nil {
+		return err
+	}
+	err = os.WriteFile(dest, contents, fileInfo.Mode())
+	return err
+}