bugfix(kubeadm): Fix UT and log optmize

cmd/kubeadm/app/apis/output/types.go

@@ -78,7 +78,7 @@ type ComponentConfigVersionState struct {
 type UpgradePlan struct {
 	metav1.TypeMeta
 
-	Components []ComponentUpgradePlan
+	Components []*ComponentUpgradePlan
 
 	ConfigVersions []ComponentConfigVersionState
 }

cmd/kubeadm/app/apis/output/v1alpha2/types.go

@@ -78,7 +78,7 @@ type ComponentConfigVersionState struct {
 type UpgradePlan struct {
 	metav1.TypeMeta
 
-	Components []ComponentUpgradePlan `json:"components"`
+	Components []*ComponentUpgradePlan `json:"components"`
 
 	ConfigVersions []ComponentConfigVersionState `json:"configVersions"`
 }

cmd/kubeadm/app/apis/output/v1alpha2/zz_generated.conversion.go

@@ -180,7 +180,7 @@ func Convert_output_Images_To_v1alpha2_Images(in *output.Images, out *Images, s
 }
 
 func autoConvert_v1alpha2_UpgradePlan_To_output_UpgradePlan(in *UpgradePlan, out *output.UpgradePlan, s conversion.Scope) error {
-	out.Components = *(*[]output.ComponentUpgradePlan)(unsafe.Pointer(&in.Components))
+	out.Components = *(*[]*output.ComponentUpgradePlan)(unsafe.Pointer(&in.Components))
 	out.ConfigVersions = *(*[]output.ComponentConfigVersionState)(unsafe.Pointer(&in.ConfigVersions))
 	return nil
 }
@@ -191,7 +191,7 @@ func Convert_v1alpha2_UpgradePlan_To_output_UpgradePlan(in *UpgradePlan, out *ou
 }
 
 func autoConvert_output_UpgradePlan_To_v1alpha2_UpgradePlan(in *output.UpgradePlan, out *UpgradePlan, s conversion.Scope) error {
-	out.Components = *(*[]ComponentUpgradePlan)(unsafe.Pointer(&in.Components))
+	out.Components = *(*[]*ComponentUpgradePlan)(unsafe.Pointer(&in.Components))
 	out.ConfigVersions = *(*[]ComponentConfigVersionState)(unsafe.Pointer(&in.ConfigVersions))
 	return nil
 }

cmd/kubeadm/app/apis/output/v1alpha2/zz_generated.deepcopy.go

@@ -128,8 +128,14 @@ func (in *UpgradePlan) DeepCopyInto(out *UpgradePlan) {
 	out.TypeMeta = in.TypeMeta
 	if in.Components != nil {
 		in, out := &in.Components, &out.Components
-		*out = make([]ComponentUpgradePlan, len(*in))
+		*out = make([]*ComponentUpgradePlan, len(*in))
-		copy(*out, *in)
+		for i := range *in {
+			if (*in)[i] != nil {
+				in, out := &(*in)[i], &(*out)[i]
+				*out = new(ComponentUpgradePlan)
+				**out = **in
+			}
+		}
 	}
 	if in.ConfigVersions != nil {
 		in, out := &in.ConfigVersions, &out.ConfigVersions

cmd/kubeadm/app/apis/output/zz_generated.deepcopy.go

@@ -128,8 +128,14 @@ func (in *UpgradePlan) DeepCopyInto(out *UpgradePlan) {
 	out.TypeMeta = in.TypeMeta
 	if in.Components != nil {
 		in, out := &in.Components, &out.Components
-		*out = make([]ComponentUpgradePlan, len(*in))
+		*out = make([]*ComponentUpgradePlan, len(*in))
-		copy(*out, *in)
+		for i := range *in {
+			if (*in)[i] != nil {
+				in, out := &(*in)[i], &(*out)[i]
+				*out = new(ComponentUpgradePlan)
+				**out = **in
+			}
+		}
 	}
 	if in.ConfigVersions != nil {
 		in, out := &in.ConfigVersions, &out.ConfigVersions

cmd/kubeadm/app/cmd/upgrade/common.go

@@ -135,14 +135,14 @@ func enforceRequirements(flags *applyPlanFlags, args []string, dryRun bool, upgr
 	cfg, legacyReconfigure, err := loadConfig(flags.cfgPath, client, !upgradeApply, printer)
 	if err != nil {
 		if apierrors.IsNotFound(err) {
-			fmt.Printf("[upgrade/config] In order to upgrade, a ConfigMap called %q in the %s namespace must exist.\n", constants.KubeadmConfigConfigMap, metav1.NamespaceSystem)
+			printer.Printf("[upgrade/config] In order to upgrade, a ConfigMap called %q in the %s namespace must exist.\n", constants.KubeadmConfigConfigMap, metav1.NamespaceSystem)
-			fmt.Println("[upgrade/config] Without this information, 'kubeadm upgrade' won't know how to configure your upgraded cluster.")
+			printer.Printf("[upgrade/config] Without this information, 'kubeadm upgrade' won't know how to configure your upgraded cluster.\n")
-			fmt.Println("")
+			printer.Printf("\n")
-			fmt.Println("[upgrade/config] Next steps:")
+			printer.Printf("[upgrade/config] Next steps:\n")
-			fmt.Printf("\t- OPTION 1: Run 'kubeadm config upload from-flags' and specify the same CLI arguments you passed to 'kubeadm init' when you created your control-plane.\n")
+			printer.Printf("\t- OPTION 1: Run 'kubeadm config upload from-flags' and specify the same CLI arguments you passed to 'kubeadm init' when you created your control-plane.\n")
-			fmt.Printf("\t- OPTION 2: Run 'kubeadm config upload from-file' and specify the same config file you passed to 'kubeadm init' when you created your control-plane.\n")
+			printer.Printf("\t- OPTION 2: Run 'kubeadm config upload from-file' and specify the same config file you passed to 'kubeadm init' when you created your control-plane.\n")
-			fmt.Printf("\t- OPTION 3: Pass a config file to 'kubeadm upgrade' using the --config flag.\n")
+			printer.Printf("\t- OPTION 3: Pass a config file to 'kubeadm upgrade' using the --config flag.\n")
-			fmt.Println("")
+			printer.Printf("\n")
 			err = errors.Errorf("the ConfigMap %q in the %s namespace used for getting configuration information was not found", constants.KubeadmConfigConfigMap, metav1.NamespaceSystem)
 		}
 		return nil, nil, nil, errors.Wrap(err, "[upgrade/config] FATAL")
@@ -203,14 +203,14 @@ func enforceRequirements(flags *applyPlanFlags, args []string, dryRun bool, upgr
 	// Check if feature gate flags used in the cluster are consistent with the set of features currently supported by kubeadm
 	if msg := features.CheckDeprecatedFlags(&features.InitFeatureGates, cfg.FeatureGates); len(msg) > 0 {
 		for _, m := range msg {
-			fmt.Printf("[upgrade/config] %s\n", m)
+			printer.Printf("[upgrade/config] %s\n", m)
 		}
 		return nil, nil, nil, errors.New("[upgrade/config] FATAL. Unable to upgrade a cluster using deprecated feature-gate flags. Please see the release notes")
 	}
 
 	// If the user told us to print this information out; do it!
 	if flags.printConfig {
-		printConfiguration(&cfg.ClusterConfiguration, os.Stdout)
+		printConfiguration(&cfg.ClusterConfiguration, os.Stdout, printer)
 	}
 
 	// Use a real version getter interface that queries the API server, the kubeadm client and the Kubernetes CI system for latest versions
@@ -218,7 +218,7 @@ func enforceRequirements(flags *applyPlanFlags, args []string, dryRun bool, upgr
 }
 
 // printConfiguration prints the external version of the API to yaml
-func printConfiguration(clustercfg *kubeadmapi.ClusterConfiguration, w io.Writer) {
+func printConfiguration(clustercfg *kubeadmapi.ClusterConfiguration, w io.Writer, printer output.Printer) {
 	// Short-circuit if cfg is nil, so we can safely get the value of the pointer below
 	if clustercfg == nil {
 		return
@@ -226,11 +226,11 @@ func printConfiguration(clustercfg *kubeadmapi.ClusterConfiguration, w io.Writer
 
 	cfgYaml, err := configutil.MarshalKubeadmConfigObject(clustercfg)
 	if err == nil {
-		fmt.Fprintln(w, "[upgrade/config] Configuration used:")
+		printer.Fprintln(w, "[upgrade/config] Configuration used:")
 
 		scanner := bufio.NewScanner(bytes.NewReader(cfgYaml))
 		for scanner.Scan() {
-			fmt.Fprintf(w, "\t%s\n", scanner.Text())
+			printer.Fprintf(w, "\t%s\n", scanner.Text())
 		}
 	}
 }

cmd/kubeadm/app/cmd/upgrade/common_test.go

@@ -139,7 +139,7 @@ func TestPrintConfiguration(t *testing.T) {
 	for _, rt := range tests {
 		t.Run(rt.name, func(t *testing.T) {
 			rt.buf = bytes.NewBufferString("")
-			printConfiguration(rt.cfg, rt.buf)
+			printConfiguration(rt.cfg, rt.buf, &output.TextPrinter{})
 			actualBytes := rt.buf.Bytes()
 			if !bytes.Equal(actualBytes, rt.expectedBytes) {
 				t.Errorf(

cmd/kubeadm/app/cmd/upgrade/plan.go

@@ -35,7 +35,6 @@ import (
 	clientset "k8s.io/client-go/kubernetes"
 	"k8s.io/klog/v2"
 	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
-	outputapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/output"
 	outputapischeme "k8s.io/kubernetes/cmd/kubeadm/app/apis/output/scheme"
 	outputapiv1alpha2 "k8s.io/kubernetes/cmd/kubeadm/app/apis/output/v1alpha2"
 	"k8s.io/kubernetes/cmd/kubeadm/app/componentconfigs"
@@ -77,9 +76,9 @@ func newCmdPlan(apf *applyPlanFlags) *cobra.Command {
 	return cmd
 }
 
-// newComponentUpgradePlan helper creates outputapiv1alpha1.ComponentUpgradePlan object
+// newComponentUpgradePlan helper creates outputapiv1alpha2.ComponentUpgradePlan object
-func newComponentUpgradePlan(name, currentVersion, newVersion string) outputapi.ComponentUpgradePlan {
+func newComponentUpgradePlan(name, currentVersion, newVersion string) *outputapiv1alpha2.ComponentUpgradePlan {
-	return outputapi.ComponentUpgradePlan{
+	return &outputapiv1alpha2.ComponentUpgradePlan{
 		Name:           name,
 		CurrentVersion: currentVersion,
 		NewVersion:     newVersion,
@@ -151,7 +150,7 @@ func (pf *upgradePlanJSONYamlPrintFlags) AllowedFormats() []string {
 // upgradePlanJSONYAMLPrinter prints upgrade plan in a JSON or YAML format
 type upgradePlanJSONYAMLPrinter struct {
 	output.ResourcePrinterWrapper
-	Buffer []outputapiv1alpha2.ComponentUpgradePlan
+	Buffer []*outputapiv1alpha2.ComponentUpgradePlan
 }
 
 // newUpgradePlanJSONYAMLPrinter creates new upgradePlanJSONYAMLPrinter object
@@ -168,15 +167,16 @@ func (p *upgradePlanJSONYAMLPrinter) PrintObj(obj runtime.Object, writer io.Writ
 	if !ok {
 		return fmt.Errorf("expected ComponentUpgradePlan, but got %+v", obj)
 	}
-	p.Buffer = append(p.Buffer, *item)
+	p.Buffer = append(p.Buffer, item)
 	return nil
 }
 
 // Close writes any buffered data and empties list of buffered components
 func (p *upgradePlanJSONYAMLPrinter) Close(writer io.Writer) {
 	plan := &outputapiv1alpha2.UpgradePlan{Components: p.Buffer}
+	// p.ResourcePrinterWrapper.Printer.PrintObj(plan, writer)
 	p.Printer.PrintObj(plan, writer)
-	p.Buffer = []outputapiv1alpha2.ComponentUpgradePlan{}
+	p.Buffer = []*outputapiv1alpha2.ComponentUpgradePlan{}
 }
 
 // upgradePlanTextPrinter prints upgrade plan in a text form
@@ -226,9 +226,9 @@ func (pf *upgradePlanTextPrintFlags) AllowedFormats() []string {
 // ToPrinter returns kubeadm printer for the text output format
 func (pf *upgradePlanTextPrintFlags) ToPrinter(outputFormat string) (output.Printer, error) {
 	if outputFormat == output.TextOutput {
-		return &upgradePlanTextPrinter{columns: []string{"COMPONENT", "CURRENT", "AVAILABLE"}}, nil
+		return &upgradePlanTextPrinter{columns: []string{"COMPONENT", "CURRENT", "TARGET"}}, nil
 	}
-	return nil, genericclioptions.NoCompatiblePrinterError{OutputFormat: &outputFormat, AllowedFormats: []string{output.TextOutput}}
+	return nil, genericclioptions.NoCompatiblePrinterError{OutputFormat: &outputFormat, AllowedFormats: []string{output.JSONOutput, output.YAMLOutput, output.TextOutput}}
 }
 
 // runPlan takes care of outputting available versions to upgrade to for the user
@@ -247,8 +247,7 @@ func runPlan(flags *planFlags, args []string, printer output.Printer) error {
 
 	// Compute which upgrade possibilities there are
 	klog.V(1).Infoln("[upgrade/plan] computing upgrade possibilities")
-	klog.V(1).Infoln("[upgrade/plan] Fetching available versions to upgrade to")
+	availUpgrades, err := upgrade.GetAvailableUpgrades(versionGetter, flags.allowExperimentalUpgrades, flags.allowRCUpgrades, isExternalEtcd, client, constants.GetStaticPodDirectory(), printer)
-	availUpgrades, err := upgrade.GetAvailableUpgrades(versionGetter, flags.allowExperimentalUpgrades, flags.allowRCUpgrades, isExternalEtcd, client, constants.GetStaticPodDirectory())
 	if err != nil {
 		return errors.Wrap(err, "[upgrade/versions] FATAL")
 	}
@@ -291,7 +290,7 @@ func runPlan(flags *planFlags, args []string, printer output.Printer) error {
 
 // TODO There is currently no way to cleanly output upgrades that involve adding, removing, or changing components
 // https://github.com/kubernetes/kubeadm/issues/810 was created to track addressing this.
-func appendDNSComponent(components []outputapi.ComponentUpgradePlan, up *upgrade.Upgrade, name string) []outputapi.ComponentUpgradePlan {
+func appendDNSComponent(components []*outputapiv1alpha2.ComponentUpgradePlan, up *upgrade.Upgrade, name string) []*outputapiv1alpha2.ComponentUpgradePlan {
 	beforeVersion := up.Before.DNSVersion
 	afterVersion := up.After.DNSVersion
 
@@ -302,7 +301,7 @@ func appendDNSComponent(components []outputapi.ComponentUpgradePlan, up *upgrade
 }
 
 // genUpgradePlan generates output-friendly upgrade plan out of upgrade.Upgrade structure
-func genUpgradePlan(up *upgrade.Upgrade, isExternalEtcd bool) (*outputapi.UpgradePlan, string, error) {
+func genUpgradePlan(up *upgrade.Upgrade, isExternalEtcd bool) (*outputapiv1alpha2.UpgradePlan, string, error) {
 	newK8sVersion, err := version.ParseSemantic(up.After.KubeVersion)
 	if err != nil {
 		return nil, "", errors.Wrapf(err, "Unable to parse normalized version %q as a semantic version", up.After.KubeVersion)
@@ -317,7 +316,7 @@ func genUpgradePlan(up *upgrade.Upgrade, isExternalEtcd bool) (*outputapi.Upgrad
 		}
 	}
 
-	components := []outputapi.ComponentUpgradePlan{}
+	components := []*outputapiv1alpha2.ComponentUpgradePlan{}
 
 	if up.CanUpgradeKubelets() {
 		// The map is of the form <old-version>:<node-count>. Here all the keys are put into a slice and sorted
@@ -339,10 +338,10 @@ func genUpgradePlan(up *upgrade.Upgrade, isExternalEtcd bool) (*outputapi.Upgrad
 		components = append(components, newComponentUpgradePlan(constants.Etcd, up.Before.EtcdVersion, up.After.EtcdVersion))
 	}
 
-	return &outputapi.UpgradePlan{Components: components}, unstableVersionFlag, nil
+	return &outputapiv1alpha2.UpgradePlan{Components: components}, unstableVersionFlag, nil
 }
 
-func getComponentConfigVersionStates(cfg *kubeadmapi.ClusterConfiguration, client clientset.Interface, cfgPath string) ([]outputapi.ComponentConfigVersionState, error) {
+func getComponentConfigVersionStates(cfg *kubeadmapi.ClusterConfiguration, client clientset.Interface, cfgPath string) ([]outputapiv1alpha2.ComponentConfigVersionState, error) {
 	docmap := kubeadmapi.DocumentMap{}
 
 	if cfgPath != "" {
@@ -361,16 +360,7 @@ func getComponentConfigVersionStates(cfg *kubeadmapi.ClusterConfiguration, clien
 }
 
 // printUpgradePlan prints a UX-friendly overview of what versions are available to upgrade to
-func printUpgradePlan(up *upgrade.Upgrade, plan *outputapi.UpgradePlan, unstableVersionFlag string, isExternalEtcd bool, w io.Writer, printer output.Printer) {
+func printUpgradePlan(up *upgrade.Upgrade, plan *outputapiv1alpha2.UpgradePlan, unstableVersionFlag string, isExternalEtcd bool, writer io.Writer, printer output.Printer) {
-	// The tab writer writes to the "real" writer w
-	tabw := tabwriter.NewWriter(w, 10, 4, 3, ' ', 0)
-
-	// endOfTable helper function flashes table writer
-	endOfTable := func() {
-		tabw.Flush()
-		printer.Fprintln(w, "")
-	}
-
 	printHeader := true
 	printManualUpgradeHeader := true
 	for _, component := range plan.Components {
@@ -379,41 +369,40 @@ func printUpgradePlan(up *upgrade.Upgrade, plan *outputapi.UpgradePlan, unstable
 			continue
 		} else if component.Name == constants.Kubelet {
 			if printManualUpgradeHeader {
-				printer.Fprintln(w, "Components that must be upgraded manually after you have upgraded the control plane with 'kubeadm upgrade apply':")
+				printer.Fprintln(writer, "Components that must be upgraded manually after you have upgraded the control plane with 'kubeadm upgrade apply':")
-				printer.Fprintln(tabw, "COMPONENT\tCURRENT\tTARGET")
+				printer.PrintObj(newComponentUpgradePlan(component.Name, component.CurrentVersion, component.NewVersion), writer)
-				printer.Fprintf(tabw, "%s\t%s\t%s\n", component.Name, component.CurrentVersion, component.NewVersion)
 				printManualUpgradeHeader = false
 			} else {
-				printer.Fprintf(tabw, "%s\t%s\t%s\n", "", component.CurrentVersion, component.NewVersion)
+				printer.PrintObj(newComponentUpgradePlan("", component.CurrentVersion, component.NewVersion), writer)
 			}
 		} else {
 			if printHeader {
 				// End of manual upgrades table
-				endOfTable()
+				printer.Flush(writer)
 
-				printer.Fprintf(w, "Upgrade to the latest %s:\n", up.Description)
+				printer.Fprintln(writer, "")
-				printer.Fprintln(w, "")
+				printer.Fprintf(writer, "Upgrade to the latest %s:\n", up.Description)
-				printer.Fprintln(tabw, "COMPONENT\tCURRENT\tTARGET")
+				printer.Fprintln(writer, "")
 				printHeader = false
 			}
-			printer.Fprintf(tabw, "%s\t%s\t%s\n", component.Name, component.CurrentVersion, component.NewVersion)
+			printer.PrintObj(newComponentUpgradePlan(component.Name, component.CurrentVersion, component.NewVersion), writer)
 		}
 	}
-	// End of control plane table
+	printer.Flush(writer)
-	endOfTable()
+	printer.Fprintln(writer, "")
 
-	//fmt.Fprintln(w, "")
+	printer.Fprintln(writer, "You can now apply the upgrade by executing the following command:")
-	printer.Fprintln(w, "You can now apply the upgrade by executing the following command:")
+	printer.Fprintln(writer, "")
-	printer.Fprintln(w, "")
+	printer.Fprintf(writer, "\tkubeadm upgrade apply %s%s\n", up.After.KubeVersion, unstableVersionFlag)
-	printer.Fprintf(w, "\tkubeadm upgrade apply %s%s\n", up.After.KubeVersion, unstableVersionFlag)
+	printer.Fprintln(writer, "")
-	printer.Fprintln(w, "")
 
 	if up.Before.KubeadmVersion != up.After.KubeadmVersion {
-		printer.Fprintf(w, "Note: Before you can perform this upgrade, you have to update kubeadm to %s.\n", up.After.KubeadmVersion)
+		printer.Fprintf(writer, "Note: Before you can perform this upgrade, you have to update kubeadm to %s.\n", up.After.KubeadmVersion)
-		printer.Fprintln(w, "")
+		printer.Fprintln(writer, "")
 	}
 
-	printLineSeparator(w, printer)
+	printLineSeparator(writer, printer)
+	printer.Close(writer)
 }
 
 // sortedSliceFromStringIntMap returns a slice of the keys in the map sorted alphabetically
@@ -445,7 +434,7 @@ func printLineSeparator(w io.Writer, printer output.Printer) {
 	printer.Fprintln(w, "")
 }
 
-func printComponentConfigVersionStates(versionStates []outputapi.ComponentConfigVersionState, w io.Writer, printer output.Printer) {
+func printComponentConfigVersionStates(versionStates []outputapiv1alpha2.ComponentConfigVersionState, w io.Writer, printer output.Printer) {
 	if len(versionStates) == 0 {
 		printer.Fprintln(w, "No information available on component configs.")
 		return

cmd/kubeadm/app/cmd/upgrade/plan_test.go

@@ -22,6 +22,7 @@ import (
 	"testing"
 
 	"k8s.io/kubernetes/cmd/kubeadm/app/phases/upgrade"
+	"k8s.io/kubernetes/cmd/kubeadm/app/util/output"
 )
 
 func TestSortedSliceFromStringIntMap(t *testing.T) {
@@ -441,13 +442,19 @@ _____________________________________________________________________
 	for _, rt := range tests {
 		t.Run(rt.name, func(t *testing.T) {
 			rt.buf = bytes.NewBufferString("")
+			outputFlags := newUpgradePlanPrintFlags(output.TextOutput)
+			printer, err := outputFlags.ToPrinter()
+			if err != nil {
+				t.Errorf("failed ToPrinter, err: %+v", err)
+			}
+
 			// Generate and print upgrade plans
 			for _, up := range rt.upgrades {
 				plan, unstableVersionFlag, err := genUpgradePlan(&up, rt.externalEtcd)
 				if err != nil {
 					t.Errorf("failed genUpgradePlan, err: %+v", err)
 				}
-				printUpgradePlan(&up, plan, unstableVersionFlag, rt.externalEtcd, rt.buf)
+				printUpgradePlan(&up, plan, unstableVersionFlag, rt.externalEtcd, rt.buf, printer)
 			}
 			actualBytes := rt.buf.Bytes()
 			if !bytes.Equal(actualBytes, rt.expectedBytes) {
@@ -460,3 +467,164 @@ _____________________________________________________________________
 		})
 	}
 }
+
+func TestPrintAvailableUpgradesStructured(t *testing.T) {
+	upgrades := []upgrade.Upgrade{
+		{
+			Description: "version in the v1.8 series",
+			Before: upgrade.ClusterState{
+				KubeVersion: "v1.8.1",
+				KubeletVersions: map[string]uint16{
+					"v1.8.1": 1,
+				},
+				KubeadmVersion: "v1.8.2",
+				DNSVersion:     "1.14.5",
+				EtcdVersion:    "3.0.17",
+			},
+			After: upgrade.ClusterState{
+				KubeVersion:    "v1.8.3",
+				KubeadmVersion: "v1.8.3",
+				DNSVersion:     "1.14.5",
+				EtcdVersion:    "3.0.17",
+			},
+		},
+	}
+
+	var tests = []struct {
+		name         string
+		outputFormat string
+		buf          *bytes.Buffer
+		expected     string
+		externalEtcd bool
+	}{
+		{
+			name:         "JSON output",
+			outputFormat: "json",
+			expected: `{
+    "kind": "UpgradePlan",
+    "apiVersion": "output.kubeadm.k8s.io/v1alpha2",
+    "components": [
+        {
+            "name": "kubelet",
+            "currentVersion": "1 x v1.8.1",
+            "newVersion": "v1.8.3"
+        },
+        {
+            "name": "kube-apiserver",
+            "currentVersion": "v1.8.1",
+            "newVersion": "v1.8.3"
+        },
+        {
+            "name": "kube-controller-manager",
+            "currentVersion": "v1.8.1",
+            "newVersion": "v1.8.3"
+        },
+        {
+            "name": "kube-scheduler",
+            "currentVersion": "v1.8.1",
+            "newVersion": "v1.8.3"
+        },
+        {
+            "name": "kube-proxy",
+            "currentVersion": "v1.8.1",
+            "newVersion": "v1.8.3"
+        },
+        {
+            "name": "CoreDNS",
+            "currentVersion": "1.14.5",
+            "newVersion": "1.14.5"
+        },
+        {
+            "name": "etcd",
+            "currentVersion": "3.0.17",
+            "newVersion": "3.0.17"
+        }
+    ],
+    "configVersions": null
+}
+`,
+		},
+		{
+			name:         "YAML output",
+			outputFormat: "yaml",
+			expected: `apiVersion: output.kubeadm.k8s.io/v1alpha2
+components:
+- currentVersion: 1 x v1.8.1
+  name: kubelet
+  newVersion: v1.8.3
+- currentVersion: v1.8.1
+  name: kube-apiserver
+  newVersion: v1.8.3
+- currentVersion: v1.8.1
+  name: kube-controller-manager
+  newVersion: v1.8.3
+- currentVersion: v1.8.1
+  name: kube-scheduler
+  newVersion: v1.8.3
+- currentVersion: v1.8.1
+  name: kube-proxy
+  newVersion: v1.8.3
+- currentVersion: 1.14.5
+  name: CoreDNS
+  newVersion: 1.14.5
+- currentVersion: 3.0.17
+  name: etcd
+  newVersion: 3.0.17
+configVersions: null
+kind: UpgradePlan
+`,
+		},
+		{
+			name:         "Text output",
+			outputFormat: "Text",
+			expected: `Components that must be upgraded manually after you have upgraded the control plane with 'kubeadm upgrade apply':
+COMPONENT   CURRENT      TARGET
+kubelet     1 x v1.8.1   v1.8.3
+
+Upgrade to the latest version in the v1.8 series:
+
+COMPONENT                 CURRENT   TARGET
+kube-apiserver            v1.8.1    v1.8.3
+kube-controller-manager   v1.8.1    v1.8.3
+kube-scheduler            v1.8.1    v1.8.3
+kube-proxy                v1.8.1    v1.8.3
+CoreDNS                   1.14.5    1.14.5
+etcd                      3.0.17    3.0.17
+
+You can now apply the upgrade by executing the following command:
+
+	kubeadm upgrade apply v1.8.3
+
+Note: Before you can perform this upgrade, you have to update kubeadm to v1.8.3.
+
+_____________________________________________________________________
+
+`,
+		},
+	}
+
+	for _, rt := range tests {
+		t.Run(rt.name, func(t *testing.T) {
+			rt.buf = bytes.NewBufferString("")
+			outputFlags := newUpgradePlanPrintFlags(rt.outputFormat)
+			printer, err := outputFlags.ToPrinter()
+			if err != nil {
+				t.Errorf("failed ToPrinter, err: %+v", err)
+			}
+
+			// Generate and print upgrade plans
+			for _, up := range upgrades {
+				plan, unstableVersionFlag, err := genUpgradePlan(&up, rt.externalEtcd)
+				if err != nil {
+					t.Errorf("failed genUpgradePlan, err: %+v", err)
+				}
+				printUpgradePlan(&up, plan, unstableVersionFlag, rt.externalEtcd, rt.buf, printer)
+			}
+
+			actual := rt.buf.String()
+			if actual != rt.expected {
+				t.Errorf("failed PrintAvailableUpgrades:\n\nexpected:\n%s\n\nactual:\n%s", rt.expected, actual)
+			}
+		})
+	}
+}

cmd/kubeadm/app/componentconfigs/configset.go

@@ -26,9 +26,9 @@ import (
 	"k8s.io/apimachinery/pkg/util/validation/field"
 	clientset "k8s.io/client-go/kubernetes"
 	"k8s.io/klog/v2"
+	outputapiv1alpha2 "k8s.io/kubernetes/cmd/kubeadm/app/apis/output/v1alpha2"
 
 	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
-	"k8s.io/kubernetes/cmd/kubeadm/app/apis/output"
 	kubeadmutil "k8s.io/kubernetes/cmd/kubeadm/app/util"
 	"k8s.io/kubernetes/cmd/kubeadm/app/util/apiclient"
 	"k8s.io/kubernetes/cmd/kubeadm/app/util/config/strict"
@@ -289,7 +289,7 @@ func FetchFromClusterWithLocalOverwrites(clusterCfg *kubeadmapi.ClusterConfigura
 
 // GetVersionStates returns a slice of ComponentConfigVersionState structs
 // describing all supported component config groups that were identified on the cluster
-func GetVersionStates(clusterCfg *kubeadmapi.ClusterConfiguration, client clientset.Interface, docmap kubeadmapi.DocumentMap) ([]output.ComponentConfigVersionState, error) {
+func GetVersionStates(clusterCfg *kubeadmapi.ClusterConfiguration, client clientset.Interface, docmap kubeadmapi.DocumentMap) ([]outputapiv1alpha2.ComponentConfigVersionState, error) {
 	// We don't want to modify clusterCfg so we make a working deep copy of it.
 	// Also, we don't want the defaulted component configs so we get rid of them.
 	scratchClusterCfg := clusterCfg.DeepCopy()
@@ -308,13 +308,13 @@ func GetVersionStates(clusterCfg *kubeadmapi.ClusterConfiguration, client client
 		}
 	}
 
-	results := []output.ComponentConfigVersionState{}
+	results := []outputapiv1alpha2.ComponentConfigVersionState{}
 	for _, handler := range known {
 		group := handler.GroupVersion.Group
 		if vererr, ok := multipleVerErrs[group]; ok {
 			// If there is an UnsupportedConfigVersionError then we are dealing with a case where the config was user
 			// supplied and requires manual upgrade
-			results = append(results, output.ComponentConfigVersionState{
+			results = append(results, outputapiv1alpha2.ComponentConfigVersionState{
 				Group:                 group,
 				CurrentVersion:        vererr.OldVersion.Version,
 				PreferredVersion:      vererr.CurrentVersion.Version,
@@ -322,7 +322,7 @@ func GetVersionStates(clusterCfg *kubeadmapi.ClusterConfiguration, client client
 			})
 		} else if _, ok := scratchClusterCfg.ComponentConfigs[group]; ok {
 			// Normally loaded component config. No manual upgrade required on behalf of users.
-			results = append(results, output.ComponentConfigVersionState{
+			results = append(results, outputapiv1alpha2.ComponentConfigVersionState{
 				Group:            group,
 				CurrentVersion:   handler.GroupVersion.Version, // Currently kubeadm supports only one version per API
 				PreferredVersion: handler.GroupVersion.Version, // group so we can get away with these being the same
@@ -331,7 +331,7 @@ func GetVersionStates(clusterCfg *kubeadmapi.ClusterConfiguration, client client
 			// This config was either not present (user did not install an addon) or the config was unsupported kubeadm
 			// generated one and is therefore skipped so we can automatically re-generate it (no action required on
 			// behalf of the user).
-			results = append(results, output.ComponentConfigVersionState{
+			results = append(results, outputapiv1alpha2.ComponentConfigVersionState{
 				Group:            group,
 				PreferredVersion: handler.GroupVersion.Version,
 			})

cmd/kubeadm/app/componentconfigs/fakeconfig_test.go

@@ -35,7 +35,7 @@ import (
 	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
 	kubeadmscheme "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/scheme"
 	kubeadmapiv1 "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1beta3"
-	outputapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/output"
+	outputapiv1alpha2 "k8s.io/kubernetes/cmd/kubeadm/app/apis/output/v1alpha2"
 	"k8s.io/kubernetes/cmd/kubeadm/app/constants"
 	kubeadmutil "k8s.io/kubernetes/cmd/kubeadm/app/util"
 )
@@ -615,12 +615,12 @@ func TestFetchFromClusterWithLocalOverwrites(t *testing.T) {
 
 func TestGetVersionStates(t *testing.T) {
 	fakeKnownContext(func() {
-		versionStateCurrent := outputapi.ComponentConfigVersionState{
+		versionStateCurrent := outputapiv1alpha2.ComponentConfigVersionState{
 			Group:            kubeadmapiv1.GroupName,
 			CurrentVersion:   currentClusterConfigVersion,
 			PreferredVersion: currentClusterConfigVersion,
 		}
-		versionStateOld := outputapi.ComponentConfigVersionState{
+		versionStateOld := outputapiv1alpha2.ComponentConfigVersionState{
 			Group:                 kubeadmapiv1.GroupName,
 			CurrentVersion:        oldClusterConfigVersion,
 			PreferredVersion:      currentClusterConfigVersion,
@@ -631,7 +631,7 @@ func TestGetVersionStates(t *testing.T) {
 			desc     string
 			obj      runtime.Object
 			config   string
-			expected outputapi.ComponentConfigVersionState
+			expected outputapiv1alpha2.ComponentConfigVersionState
 		}{
 			{
 				desc:     "appropriate cluster object without overwrite",
@@ -687,7 +687,7 @@ func TestGetVersionStates(t *testing.T) {
 			{
 				desc: "old signed config without an overwrite",
 				obj:  testClusterConfigMap(oldFooClusterConfig, true),
-				expected: outputapi.ComponentConfigVersionState{
+				expected: outputapiv1alpha2.ComponentConfigVersionState{
 					Group:            kubeadmapiv1.GroupName,
 					CurrentVersion:   "", // The config is treated as if it's missing
 					PreferredVersion: currentClusterConfigVersion,

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

@@ -26,6 +26,7 @@ import (
 
 	kubeadmconstants "k8s.io/kubernetes/cmd/kubeadm/app/constants"
 	"k8s.io/kubernetes/cmd/kubeadm/app/phases/addons/dns"
+	"k8s.io/kubernetes/cmd/kubeadm/app/util/output"
 )
 
 // Upgrade defines an upgrade possibility to upgrade from a current version to a new one
@@ -72,7 +73,9 @@ type ClusterState struct {
 
 // GetAvailableUpgrades fetches all versions from the specified VersionGetter and computes which
 // kinds of upgrades can be performed
-func GetAvailableUpgrades(versionGetterImpl VersionGetter, experimentalUpgradesAllowed, rcUpgradesAllowed, externalEtcd bool, client clientset.Interface, manifestsDir string) ([]Upgrade, error) {
+func GetAvailableUpgrades(versionGetterImpl VersionGetter, experimentalUpgradesAllowed, rcUpgradesAllowed, externalEtcd bool, client clientset.Interface, manifestsDir string, printer output.Printer) ([]Upgrade, error) {
+	printer.Printf("[upgrade] Fetching available versions to upgrade to\n")
+
 	// Collect the upgrades kubeadm can do in this list
 	upgrades := []Upgrade{}
 
@@ -81,14 +84,14 @@ func GetAvailableUpgrades(versionGetterImpl VersionGetter, experimentalUpgradesA
 	if err != nil {
 		return upgrades, err
 	}
-	fmt.Printf("[upgrade/versions] Cluster version: %s\n", clusterVersionStr)
+	printer.Printf("[upgrade/versions] Cluster version: %s\n", clusterVersionStr)
 
 	// Get current kubeadm CLI version
 	kubeadmVersionStr, kubeadmVersion, err := versionGetterImpl.KubeadmVersion()
 	if err != nil {
 		return upgrades, err
 	}
-	fmt.Printf("[upgrade/versions] kubeadm version: %s\n", kubeadmVersionStr)
+	printer.Printf("[upgrade/versions] kubeadm version: %s\n", kubeadmVersionStr)
 
 	// Get and output the current latest stable version
 	stableVersionStr, stableVersion, err := versionGetterImpl.VersionFromCILabel("stable", "stable version")
@@ -97,7 +100,7 @@ func GetAvailableUpgrades(versionGetterImpl VersionGetter, experimentalUpgradesA
 		klog.Warningf("[upgrade/versions] WARNING: Falling back to current kubeadm version as latest stable version")
 		stableVersionStr, stableVersion = kubeadmVersionStr, kubeadmVersion
 	} else {
-		fmt.Printf("[upgrade/versions] Target version: %s\n", stableVersionStr)
+		printer.Printf("[upgrade/versions] Target version: %s\n", stableVersionStr)
 	}
 
 	// Get the kubelet versions in the cluster
@@ -146,7 +149,7 @@ func GetAvailableUpgrades(versionGetterImpl VersionGetter, experimentalUpgradesA
 		if err != nil {
 			klog.Warningf("[upgrade/versions] WARNING: %v\n", err)
 		} else {
-			fmt.Printf("[upgrade/versions] Latest %s: %s\n", description, patchVersionStr)
+			printer.Printf("[upgrade/versions] Latest %s: %s\n", description, patchVersionStr)
 
 			// Check if a minor version upgrade is possible when a patch release exists
 			// It's only possible if the latest patch version is higher than the current patch version
@@ -264,6 +267,9 @@ func GetAvailableUpgrades(versionGetterImpl VersionGetter, experimentalUpgradesA
 		}
 	}
 
+	// Add a newline in the end of this output to leave some space to the next output section
+	printer.Printf("\n")
+
 	return upgrades, nil
 }
 

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

@@ -31,6 +31,7 @@ import (
 	clientsetfake "k8s.io/client-go/kubernetes/fake"
 
 	"k8s.io/kubernetes/cmd/kubeadm/app/constants"
+	"k8s.io/kubernetes/cmd/kubeadm/app/util/output"
 )
 
 type fakeVersionGetter struct {
@@ -652,7 +653,7 @@ func TestGetAvailableUpgrades(t *testing.T) {
 				t.Fatalf("Unable to create test static pod manifest: %v", err)
 			}
 
-			actualUpgrades, actualErr := GetAvailableUpgrades(rt.vg, rt.allowExperimental, rt.allowRCs, rt.externalEtcd, client, manifestsDir)
+			actualUpgrades, actualErr := GetAvailableUpgrades(rt.vg, rt.allowExperimental, rt.allowRCs, rt.externalEtcd, client, manifestsDir, &output.TextPrinter{})
 			if !reflect.DeepEqual(actualUpgrades, rt.expectedUpgrades) {
 				t.Errorf("failed TestGetAvailableUpgrades\n\texpected upgrades: %v\n\tgot: %v", rt.expectedUpgrades, actualUpgrades)
 			}