Merge pull request #114695 from chendave/fix_cross_move

kubeadm: backup kubelet config for "upgrade node" and "upgrade apply"

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

@@ -18,8 +18,10 @@ package upgrade
 
 import (
 	"context"
+	"fmt"
 	"io"
 	"os"
+	"path/filepath"
 
 	"github.com/pkg/errors"
 
@@ -38,6 +40,7 @@ import (
 	kubeletphase "k8s.io/kubernetes/cmd/kubeadm/app/phases/kubelet"
 	patchnodephase "k8s.io/kubernetes/cmd/kubeadm/app/phases/patchnode"
 	"k8s.io/kubernetes/cmd/kubeadm/app/phases/uploadconfig"
+	kubeadmutil "k8s.io/kubernetes/cmd/kubeadm/app/util"
 	dryrunutil "k8s.io/kubernetes/cmd/kubeadm/app/util/dryrun"
 )
 
@@ -59,7 +62,7 @@ func PerformPostUpgradeTasks(client clientset.Interface, cfg *kubeadmapi.InitCon
 	}
 
 	// Write the new kubelet config down to disk and the env file if needed
-	if err := writeKubeletConfigFiles(client, cfg, patchesDir, dryRun, out); err != nil {
+	if err := WriteKubeletConfigFiles(cfg, patchesDir, dryRun, out); err != nil {
 		errs = append(errs, err)
 	}
 
@@ -153,12 +156,36 @@ func PerformPostUpgradeTasks(client clientset.Interface, cfg *kubeadmapi.InitCon
 	return errorsutil.NewAggregate(errs)
 }
 
-func writeKubeletConfigFiles(client clientset.Interface, cfg *kubeadmapi.InitConfiguration, patchesDir string, dryRun bool, out io.Writer) error {
+func WriteKubeletConfigFiles(cfg *kubeadmapi.InitConfiguration, patchesDir string, dryRun bool, out io.Writer) error {
+	// Set up the kubelet directory to use. If dry-running, this will return a fake directory
 	kubeletDir, err := GetKubeletDir(dryRun)
 	if err != nil {
 		// The error here should never occur in reality, would only be thrown if /tmp doesn't exist on the machine.
 		return err
 	}
+
+	// Create a copy of the kubelet config file in the /etc/kubernetes/tmp/ folder.
+	backupDir, err := kubeadmconstants.CreateTempDirForKubeadm(kubeadmconstants.KubernetesDir, "kubeadm-kubelet-config")
+	if err != nil {
+		return err
+	}
+	src := filepath.Join(kubeletDir, kubeadmconstants.KubeletConfigurationFileName)
+	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)
+		if err != nil {
+			return errors.Wrapf(err, "error backing up the kubelet config file, output: %q", output)
+		}
+	} else {
+		fmt.Printf("[dryrun] Would back up kubelet config file to %s\n", dest)
+	}
+
 	errs := []error{}
 	// Write the configuration for the kubelet down to disk so the upgraded kubelet can start with fresh config
 	if err := kubeletphase.WriteConfigToDisk(&cfg.ClusterConfiguration, kubeletDir, patchesDir, out); err != nil {
@@ -166,7 +193,10 @@ func writeKubeletConfigFiles(client clientset.Interface, cfg *kubeadmapi.InitCon
 	}
 
 	if dryRun { // Print what contents would be written
-		dryrunutil.PrintDryRunFile(kubeadmconstants.KubeletConfigurationFileName, kubeletDir, kubeadmconstants.KubeletRunDirectory, os.Stdout)
+		err := dryrunutil.PrintDryRunFile(kubeadmconstants.KubeletConfigurationFileName, kubeletDir, kubeadmconstants.KubeletRunDirectory, os.Stdout)
+		if err != nil {
+			errs = append(errs, errors.Wrap(err, "error printing files on dryrun"))
+		}
 	}
 	return errorsutil.NewAggregate(errs)
 }

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

@@ -19,12 +19,16 @@ package upgrade
 import (
 	"os"
 	"path/filepath"
+	"regexp"
 	"strings"
 	"testing"
 
 	"github.com/pkg/errors"
 
+	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
+	"k8s.io/kubernetes/cmd/kubeadm/app/componentconfigs"
 	"k8s.io/kubernetes/cmd/kubeadm/app/constants"
+	"k8s.io/kubernetes/cmd/kubeadm/app/preflight"
 	testutil "k8s.io/kubernetes/cmd/kubeadm/test"
 )
 
@@ -101,3 +105,104 @@ func TestRollbackFiles(t *testing.T) {
 		t.Fatalf("Expected error contains %q, got %v", errString, err)
 	}
 }
+
+func TestWriteKubeletConfigFiles(t *testing.T) {
+	// exit early if the user doesn't have root permission as the test needs to create /etc/kubernetes directory
+	// while the permission should be granted to the user.
+	isPrivileged := preflight.IsPrivilegedUserCheck{}
+	if _, err := isPrivileged.Check(); err != nil {
+		return
+	}
+	testCases := []struct {
+		name       string
+		dryrun     bool
+		patchesDir string
+		errPattern string
+		cfg        *kubeadmapi.InitConfiguration
+	}{
+		// Be careful that if the dryrun is set to false and the test is run on a live cluster, the kubelet config file might be overwritten.
+		// However, you should be able to find the original config file in /etc/kubernetes/tmp/kubeadm-kubelet-configxxx folder.
+		// The test haven't clean up the temporary file created under /etc/kubernetes/tmp/ as that could be accidentally delete other files in
+		// that folder as well which might be unexpected.
+		{
+			name:   "write kubelet config file successfully",
+			dryrun: true,
+			cfg: &kubeadmapi.InitConfiguration{
+				ClusterConfiguration: kubeadmapi.ClusterConfiguration{
+					ComponentConfigs: kubeadmapi.ComponentConfigMap{
+						componentconfigs.KubeletGroup: &componentConfig{},
+					},
+				},
+			},
+		},
+		{
+			name:       "aggregate errs: no kubelet config file and cannot read config file",
+			dryrun:     true,
+			errPattern: "no kubelet component config found.*no such file or directory",
+			cfg:        &kubeadmapi.InitConfiguration{},
+		},
+		{
+			name:       "only one err: patch dir does not exist",
+			dryrun:     true,
+			patchesDir: "Bogus",
+			errPattern: "could not list patch files for path \"Bogus\"",
+			cfg: &kubeadmapi.InitConfiguration{
+				ClusterConfiguration: kubeadmapi.ClusterConfiguration{
+					ComponentConfigs: kubeadmapi.ComponentConfigMap{
+						componentconfigs.KubeletGroup: &componentConfig{},
+					},
+				},
+			},
+		},
+	}
+	for _, tc := range testCases {
+		err := WriteKubeletConfigFiles(tc.cfg, tc.patchesDir, tc.dryrun, os.Stdout)
+		if err != nil && tc.errPattern != "" {
+			if match, _ := regexp.MatchString(tc.errPattern, err.Error()); !match {
+				t.Fatalf("Expected error contains %q, got %v", tc.errPattern, err.Error())
+			}
+		}
+		if err == nil && len(tc.errPattern) != 0 {
+			t.Fatalf("WriteKubeletConfigFiles didn't return error expected %s", tc.errPattern)
+		}
+	}
+}
+
+// Just some stub code, the code could be enriched when necessary.
+type componentConfig struct {
+	userSupplied bool
+}
+
+func (cc *componentConfig) DeepCopy() kubeadmapi.ComponentConfig {
+	result := &componentConfig{}
+	return result
+}
+
+func (cc *componentConfig) Marshal() ([]byte, error) {
+	return nil, nil
+}
+
+func (cc *componentConfig) Unmarshal(docmap kubeadmapi.DocumentMap) error {
+	return nil
+}
+
+func (cc *componentConfig) Get() interface{} {
+	return &cc
+}
+
+func (cc *componentConfig) Set(cfg interface{}) {
+}
+
+func (cc *componentConfig) Default(_ *kubeadmapi.ClusterConfiguration, _ *kubeadmapi.APIEndpoint, _ *kubeadmapi.NodeRegistrationOptions) {
+}
+
+func (cc *componentConfig) Mutate() error {
+	return nil
+}
+
+func (cc *componentConfig) IsUserSupplied() bool {
+	return false
+}
+func (cc *componentConfig) SetUserSupplied(userSupplied bool) {
+	cc.userSupplied = userSupplied
+}