Merge pull request kubernetes#69886 from bart0sh/PR0030-kubeadm-fix-1…

…054-upgrade-same-version

kubeadm: skip upgrade if manifest is not changed

cmd/kubeadm/app/phases/upgrade/BUILD

@@ -37,6 +37,7 @@ go_library(
         "//cmd/kubeadm/app/util/apiclient:go_default_library",
         "//cmd/kubeadm/app/util/dryrun:go_default_library",
         "//cmd/kubeadm/app/util/etcd:go_default_library",
+        "//cmd/kubeadm/app/util/staticpod:go_default_library",
         "//pkg/version:go_default_library",
         "//staging/src/k8s.io/api/apps/v1:go_default_library",
         "//staging/src/k8s.io/api/core/v1:go_default_library",

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

@@ -32,6 +32,7 @@ import (
 	"k8s.io/kubernetes/cmd/kubeadm/app/util"
 	"k8s.io/kubernetes/cmd/kubeadm/app/util/apiclient"
 	etcdutil "k8s.io/kubernetes/cmd/kubeadm/app/util/etcd"
+	"k8s.io/kubernetes/cmd/kubeadm/app/util/staticpod"
 )
 
 const (
@@ -201,6 +202,16 @@ func upgradeComponent(component string, waiter apiclient.Waiter, pathMgr StaticP
 	// Store the backup path in the recover list. If something goes wrong now, this component will be rolled back.
 	recoverManifests[component] = backupManifestPath
 
+	// Skip upgrade if current and new manifests are equal
+	equal, err := staticpod.ManifestFilesAreEqual(currentManifestPath, newManifestPath)
+	if err != nil {
+		return err
+	}
+	if equal {
+		fmt.Printf("[upgrade/staticpods] current and new manifests of %s are equal, skipping upgrade\n", component)
+		return nil
+	}
+
 	// Move the old manifest into the old-manifests directory
 	if err := pathMgr.MoveFile(currentManifestPath, backupManifestPath); err != nil {
 		return rollbackOldManifests(recoverManifests, err, pathMgr, recoverEtcd)

cmd/kubeadm/app/util/staticpod/utils.go

@@ -17,6 +17,7 @@ limitations under the License.
 package staticpod
 
 import (
+	"bytes"
 	"fmt"
 	"io/ioutil"
 	"net"
@@ -288,3 +289,17 @@ func GetProbeAddress(cfg *kubeadmapi.InitConfiguration, componentName string) st
 	}
 	return "127.0.0.1"
 }
+
+// ManifestFilesAreEqual compares 2 files. It returns true if their contents are equal, false otherwise
+func ManifestFilesAreEqual(path1, path2 string) (bool, error) {
+	content1, err := ioutil.ReadFile(path1)
+	if err != nil {
+		return false, err
+	}
+	content2, err := ioutil.ReadFile(path2)
+	if err != nil {
+		return false, err
+	}
+
+	return bytes.Equal(content1, content2), nil
+}

cmd/kubeadm/app/util/staticpod/utils_test.go

@@ -22,6 +22,7 @@ import (
 	"path/filepath"
 	"reflect"
 	"sort"
+	"strconv"
 	"testing"
 
 	"k8s.io/api/core/v1"
@@ -622,3 +623,73 @@ func TestReadStaticPodFromDisk(t *testing.T) {
 		}
 	}
 }
+
+func TestManifestFilesAreEqual(t *testing.T) {
+	var tests = []struct {
+		description    string
+		podYamls       []string
+		expectedResult bool
+		expectErr      bool
+	}{
+		{
+			description:    "manifests are equal",
+			podYamls:       []string{validPod, validPod},
+			expectedResult: true,
+			expectErr:      false,
+		},
+		{
+			description:    "manifests are not equal",
+			podYamls:       []string{validPod, validPod + "\n"},
+			expectedResult: false,
+			expectErr:      false,
+		},
+		{
+			description:    "first manifest doesn't exist",
+			podYamls:       []string{validPod, ""},
+			expectedResult: false,
+			expectErr:      true,
+		},
+		{
+			description:    "second manifest doesn't exist",
+			podYamls:       []string{"", validPod},
+			expectedResult: false,
+			expectErr:      true,
+		},
+	}
+
+	for _, rt := range tests {
+		tmpdir := testutil.SetupTempDir(t)
+		defer os.RemoveAll(tmpdir)
+
+		// write 2 manifests
+		for i := 0; i < 2; i++ {
+			if rt.podYamls[i] != "" {
+				manifestPath := filepath.Join(tmpdir, strconv.Itoa(i)+".yaml")
+				err := ioutil.WriteFile(manifestPath, []byte(rt.podYamls[i]), 0644)
+				if err != nil {
+					t.Fatalf("Failed to write manifest file\n%s\n\tfatal error: %v", rt.description, err)
+				}
+			}
+		}
+
+		// compare them
+		result, actualErr := ManifestFilesAreEqual(filepath.Join(tmpdir, "0.yaml"), filepath.Join(tmpdir, "1.yaml"))
+		if result != rt.expectedResult {
+			t.Errorf(
+				"ManifestFilesAreEqual failed\n%s\nexpected result: %t\nactual result: %t",
+				rt.description,
+				rt.expectedResult,
+				result,
+			)
+		}
+		if (actualErr != nil) != rt.expectErr {
+			t.Errorf(
+				"ManifestFilesAreEqual failed\n%s\n\texpected error: %t\n\tgot: %t\n\tactual error: %v",
+				rt.description,
+				rt.expectErr,
+				(actualErr != nil),
+				actualErr,
+			)
+		}
+	}
+}