Replace fmt.Print with printer in upgrade plan code and fix configVer…

…sions are not printed when output is json or yaml

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

@@ -176,7 +176,7 @@ func enforceRequirements(flags *applyPlanFlags, args []string, dryRun bool, upgr
 	}
 
 	// Run healthchecks against the cluster
-	if err := upgrade.CheckClusterHealth(client, &cfg.ClusterConfiguration, ignorePreflightErrorsSet); err != nil {
+	if err := upgrade.CheckClusterHealth(client, &cfg.ClusterConfiguration, ignorePreflightErrorsSet, printer); err != nil {
 		return nil, nil, nil, errors.Wrap(err, "[upgrade/health] FATAL")
 	}
 

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

@@ -158,7 +158,8 @@ func (pf *upgradePlanJSONYamlPrintFlags) AllowedFormats() []string {
 // upgradePlanJSONYAMLPrinter prints upgrade plan in a JSON or YAML format
 type upgradePlanJSONYAMLPrinter struct {
 	output.ResourcePrinterWrapper
-	Buffer []outputapiv1alpha2.ComponentUpgradePlan
+	Components     []outputapiv1alpha2.ComponentUpgradePlan
+	ConfigVersions []outputapiv1alpha2.ComponentConfigVersionState
 }
 
 // newUpgradePlanJSONYAMLPrinter creates a new upgradePlanJSONYAMLPrinter object
@@ -175,7 +176,7 @@ func (p *upgradePlanJSONYAMLPrinter) PrintObj(obj runtime.Object, writer io.Writ
 	if !ok {
 		return errors.Errorf("expected ComponentUpgradePlan, but got %+v", obj)
 	}
-	p.Buffer = append(p.Buffer, *item)
+	p.Components = append(p.Components, *item)
 	return nil
 }
 
@@ -184,19 +185,18 @@ func (p *upgradePlanJSONYAMLPrinter) Flush(writer io.Writer, last bool) {
 	if !last {
 		return
 	}
-	if len(p.Buffer) == 0 {
+	if len(p.Components) == 0 || len(p.ConfigVersions) == 0 {
 		return
 	}
-	plan := &outputapiv1alpha2.UpgradePlan{Components: p.Buffer}
+	plan := &outputapiv1alpha2.UpgradePlan{Components: p.Components, ConfigVersions: p.ConfigVersions}
 	if err := p.Printer.PrintObj(plan, writer); err != nil {
 		fmt.Fprintf(os.Stderr, "could not flush output buffer: %v\n", err)
 	}
+	p.Components = p.Components[:0]
 }
 
-// Close empties the list of buffered components
-func (p *upgradePlanJSONYAMLPrinter) Close(writer io.Writer) {
-	p.Buffer = p.Buffer[:0]
-}
+// Close does nothing.
+func (p *upgradePlanJSONYAMLPrinter) Close(writer io.Writer) {}
 
 // upgradePlanTextPrinter prints upgrade plan in a text form
 type upgradePlanTextPrinter struct {
@@ -284,6 +284,11 @@ func runPlan(flags *planFlags, args []string, printer output.Printer) error {
 		return nil
 	}
 
+	// A workaround to set the configVersionStates in the printer
+	if p, ok := printer.(*upgradePlanJSONYAMLPrinter); ok {
+		p.ConfigVersions = configVersionStates
+	}
+
 	// Generate and print upgrade plans
 	for _, up := range availUpgrades {
 		plan, unstableVersionFlag, err := genUpgradePlan(&up, isExternalEtcd)
@@ -387,6 +392,7 @@ func printUpgradePlan(up *upgrade.Upgrade, plan *outputapiv1alpha2.UpgradePlan,
 			printer.PrintObj(&plan, writer)
 		}
 	}
+
 	printer.Flush(writer, true)
 
 	printer.Fprintln(writer, "You can now apply the upgrade by executing the following command:")

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

@@ -216,7 +216,7 @@ func GetAvailableUpgrades(versionGetterImpl VersionGetter, experimentalUpgradesA
 		if err != nil {
 			return upgrades, err
 		}
-		fmt.Printf("[upgrade/versions] Latest %s: %s\n", "experimental version", latestVersionStr)
+		printer.Printf("[upgrade/versions] Latest %s: %s\n", "experimental version", latestVersionStr)
 
 		minorUnstable := latestVersion.Components()[1]
 		// Get and output the current latest unstable version
@@ -225,7 +225,7 @@ func GetAvailableUpgrades(versionGetterImpl VersionGetter, experimentalUpgradesA
 		if err != nil {
 			return upgrades, err
 		}
-		fmt.Printf("[upgrade/versions] Latest %s: %s\n", "previous version", previousBranchLatestVersionStr)
+		printer.Printf("[upgrade/versions] Latest %s: %s\n", "previous version", previousBranchLatestVersionStr)
 
 		// If that previous latest version is an RC, RCs are allowed and the cluster version is lower than the RC version, show the upgrade
 		if rcUpgradesAllowed && rcUpgradePossible(clusterVersion, previousBranchLatestVersion) {

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

@@ -38,6 +38,7 @@ import (
 	"k8s.io/kubernetes/cmd/kubeadm/app/constants"
 	"k8s.io/kubernetes/cmd/kubeadm/app/images"
 	"k8s.io/kubernetes/cmd/kubeadm/app/preflight"
+	"k8s.io/kubernetes/cmd/kubeadm/app/util/output"
 )
 
 // healthCheck is a helper struct for easily performing healthchecks against the cluster and printing the output
@@ -66,8 +67,8 @@ func (c *healthCheck) Name() string {
 // - the API /healthz endpoint is healthy
 // - all control-plane Nodes are Ready
 // - (if static pod-hosted) that all required Static Pod manifests exist on disk
-func CheckClusterHealth(client clientset.Interface, cfg *kubeadmapi.ClusterConfiguration, ignoreChecksErrors sets.Set[string]) error {
-	fmt.Println("[upgrade] Running cluster health checks")
+func CheckClusterHealth(client clientset.Interface, cfg *kubeadmapi.ClusterConfiguration, ignoreChecksErrors sets.Set[string], printer output.Printer) error {
+	printer.Println("[upgrade] Running cluster health checks")
 
 	healthChecks := []preflight.Checker{
 		&healthCheck{