in the new output API output.kubeadm.k8s.io/v1alpha3 modify the UpgradePlan structure to include a list of multiple available upgrades.

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

@@ -33,6 +33,7 @@ import (
 func Funcs(codecs runtimeserializer.CodecFactory) []interface{} {
 	return []interface{}{
 		fuzzBootstrapToken,
+		fuzzUpgradePlan,
 	}
 }
 
@@ -45,3 +46,10 @@ func fuzzBootstrapToken(obj *output.BootstrapToken, c fuzz.Continue) {
 	obj.Usages = []string{"authentication", "signing"}
 	obj.Groups = []string{constants.NodeBootstrapTokenAuthGroup}
 }
+
+// TODO: Remove this func when v1alpha2 is removed
+func fuzzUpgradePlan(obj *output.UpgradePlan, c fuzz.Continue) {
+	// Pin the value to avoid round tripping the AvailableUpgrades field
+	// which is not present in the v1alpha2 version.
+	obj.AvailableUpgrades = nil
+}

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

@@ -73,14 +73,28 @@ type ComponentConfigVersionState struct {
 
 // +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
 
+// AvailableUpgrade represents information for a single available upgrade.
+type AvailableUpgrade struct {
+	metav1.TypeMeta
+
+	Description string
+
+	Components []ComponentUpgradePlan
+}
+
+// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
+
 // UpgradePlan represents information about upgrade plan for the output
 // produced by 'kubeadm upgrade plan'
 type UpgradePlan struct {
 	metav1.TypeMeta
 
-	Components []ComponentUpgradePlan
+	AvailableUpgrades []AvailableUpgrade
 
 	ConfigVersions []ComponentConfigVersionState
+
+	// TODO: Remove this field when v1alpha2 is removed
+	Components []ComponentUpgradePlan
 }
 
 // Certificate represents information for a certificate or a certificate authority when using the check-expiration command.

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

@@ -0,0 +1,28 @@
+/*
+Copyright 2024 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 v1alpha2
+
+import (
+	"k8s.io/apimachinery/pkg/conversion"
+
+	"k8s.io/kubernetes/cmd/kubeadm/app/apis/output"
+)
+
+// Convert_output_UpgradePlan_To_v1alpha2_UpgradePlan converts a private UpgradePlan to public UpgradePlan.
+func Convert_output_UpgradePlan_To_v1alpha2_UpgradePlan(in *output.UpgradePlan, out *UpgradePlan, s conversion.Scope) error {
+	return autoConvert_output_UpgradePlan_To_v1alpha2_UpgradePlan(in, out, s)
+}

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

@@ -81,7 +81,7 @@ func RegisterConversions(s *runtime.Scheme) error {
 	}); err != nil {
 		return err
 	}
-	if err := s.AddGeneratedConversionFunc((*output.UpgradePlan)(nil), (*UpgradePlan)(nil), func(a, b interface{}, scope conversion.Scope) error {
+	if err := s.AddConversionFunc((*output.UpgradePlan)(nil), (*UpgradePlan)(nil), func(a, b interface{}, scope conversion.Scope) error {
 		return Convert_output_UpgradePlan_To_v1alpha2_UpgradePlan(a.(*output.UpgradePlan), b.(*UpgradePlan), scope)
 	}); err != nil {
 		return err
@@ -191,12 +191,8 @@ 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))
+	// WARNING: in.AvailableUpgrades requires manual conversion: does not exist in peer-type
 	out.ConfigVersions = *(*[]ComponentConfigVersionState)(unsafe.Pointer(&in.ConfigVersions))
+	out.Components = *(*[]ComponentUpgradePlan)(unsafe.Pointer(&in.Components))
 	return nil
 }
-
-// Convert_output_UpgradePlan_To_v1alpha2_UpgradePlan is an autogenerated conversion function.
-func Convert_output_UpgradePlan_To_v1alpha2_UpgradePlan(in *output.UpgradePlan, out *UpgradePlan, s conversion.Scope) error {
-	return autoConvert_output_UpgradePlan_To_v1alpha2_UpgradePlan(in, out, s)
-}

cmd/kubeadm/app/apis/output/v1alpha3/conversion.go

@@ -0,0 +1,28 @@
+/*
+Copyright 2024 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 v1alpha3
+
+import (
+	"k8s.io/apimachinery/pkg/conversion"
+
+	"k8s.io/kubernetes/cmd/kubeadm/app/apis/output"
+)
+
+// Convert_output_UpgradePlan_To_v1alpha3_UpgradePlan converts a private UpgradePlan to public UpgradePlan.
+func Convert_output_UpgradePlan_To_v1alpha3_UpgradePlan(in *output.UpgradePlan, out *UpgradePlan, s conversion.Scope) error {
+	return autoConvert_output_UpgradePlan_To_v1alpha3_UpgradePlan(in, out, s)
+}

cmd/kubeadm/app/apis/output/v1alpha3/doc.go

@@ -27,4 +27,6 @@ limitations under the License.
 // Changes since v1alpha2:
 //   - Added support for outputting certificate expiration information for "kubeadm certs check-expiration"
 //     with the CertificateExpirationInfo structure.
+//   - Introduce a (breaking) change to the UpgradePlan structure used by "kubeadm upgrade plan".
+//     UpgradePlan now contains a list of AvailableUpgrade structures.
 package v1alpha3 // import "k8s.io/kubernetes/cmd/kubeadm/app/apis/output/v1alpha3"

cmd/kubeadm/app/apis/output/v1alpha3/types.go

@@ -73,14 +73,25 @@ type ComponentConfigVersionState struct {
 
 // +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
 
+// AvailableUpgrade represents information for a single available upgrade.
+type AvailableUpgrade struct {
+	metav1.TypeMeta
+
+	Description string `json:"description"`
+
+	Components []ComponentUpgradePlan `json:"components"`
+}
+
+// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
+
 // UpgradePlan represents information about upgrade plan for the output
 // produced by 'kubeadm upgrade plan'
 type UpgradePlan struct {
 	metav1.TypeMeta
 
-	Components []ComponentUpgradePlan `json:"components"`
+	AvailableUpgrades []AvailableUpgrade `json:"availableUpgrades,omitempty"`
 
-	ConfigVersions []ComponentConfigVersionState `json:"configVersions"`
+	ConfigVersions []ComponentConfigVersionState `json:"configVersions,omitempty"`
 }
 
 // Certificate represents information for a certificate or a certificate authority when using the check-expiration command.

cmd/kubeadm/app/apis/output/v1alpha3/zz_generated.conversion.go

@@ -36,6 +36,16 @@ func init() {
 // RegisterConversions adds conversion functions to the given scheme.
 // Public to allow building arbitrary schemes.
 func RegisterConversions(s *runtime.Scheme) error {
+	if err := s.AddGeneratedConversionFunc((*AvailableUpgrade)(nil), (*output.AvailableUpgrade)(nil), func(a, b interface{}, scope conversion.Scope) error {
+		return Convert_v1alpha3_AvailableUpgrade_To_output_AvailableUpgrade(a.(*AvailableUpgrade), b.(*output.AvailableUpgrade), scope)
+	}); err != nil {
+		return err
+	}
+	if err := s.AddGeneratedConversionFunc((*output.AvailableUpgrade)(nil), (*AvailableUpgrade)(nil), func(a, b interface{}, scope conversion.Scope) error {
+		return Convert_output_AvailableUpgrade_To_v1alpha3_AvailableUpgrade(a.(*output.AvailableUpgrade), b.(*AvailableUpgrade), scope)
+	}); err != nil {
+		return err
+	}
 	if err := s.AddGeneratedConversionFunc((*BootstrapToken)(nil), (*output.BootstrapToken)(nil), func(a, b interface{}, scope conversion.Scope) error {
 		return Convert_v1alpha3_BootstrapToken_To_output_BootstrapToken(a.(*BootstrapToken), b.(*output.BootstrapToken), scope)
 	}); err != nil {
@@ -101,7 +111,7 @@ func RegisterConversions(s *runtime.Scheme) error {
 	}); err != nil {
 		return err
 	}
-	if err := s.AddGeneratedConversionFunc((*output.UpgradePlan)(nil), (*UpgradePlan)(nil), func(a, b interface{}, scope conversion.Scope) error {
+	if err := s.AddConversionFunc((*output.UpgradePlan)(nil), (*UpgradePlan)(nil), func(a, b interface{}, scope conversion.Scope) error {
 		return Convert_output_UpgradePlan_To_v1alpha3_UpgradePlan(a.(*output.UpgradePlan), b.(*UpgradePlan), scope)
 	}); err != nil {
 		return err
@@ -109,6 +119,28 @@ func RegisterConversions(s *runtime.Scheme) error {
 	return nil
 }
 
+func autoConvert_v1alpha3_AvailableUpgrade_To_output_AvailableUpgrade(in *AvailableUpgrade, out *output.AvailableUpgrade, s conversion.Scope) error {
+	out.Description = in.Description
+	out.Components = *(*[]output.ComponentUpgradePlan)(unsafe.Pointer(&in.Components))
+	return nil
+}
+
+// Convert_v1alpha3_AvailableUpgrade_To_output_AvailableUpgrade is an autogenerated conversion function.
+func Convert_v1alpha3_AvailableUpgrade_To_output_AvailableUpgrade(in *AvailableUpgrade, out *output.AvailableUpgrade, s conversion.Scope) error {
+	return autoConvert_v1alpha3_AvailableUpgrade_To_output_AvailableUpgrade(in, out, s)
+}
+
+func autoConvert_output_AvailableUpgrade_To_v1alpha3_AvailableUpgrade(in *output.AvailableUpgrade, out *AvailableUpgrade, s conversion.Scope) error {
+	out.Description = in.Description
+	out.Components = *(*[]ComponentUpgradePlan)(unsafe.Pointer(&in.Components))
+	return nil
+}
+
+// Convert_output_AvailableUpgrade_To_v1alpha3_AvailableUpgrade is an autogenerated conversion function.
+func Convert_output_AvailableUpgrade_To_v1alpha3_AvailableUpgrade(in *output.AvailableUpgrade, out *AvailableUpgrade, s conversion.Scope) error {
+	return autoConvert_output_AvailableUpgrade_To_v1alpha3_AvailableUpgrade(in, out, s)
+}
+
 func autoConvert_v1alpha3_BootstrapToken_To_output_BootstrapToken(in *BootstrapToken, out *output.BootstrapToken, s conversion.Scope) error {
 	out.BootstrapToken = in.BootstrapToken
 	return nil
@@ -252,7 +284,7 @@ func Convert_output_Images_To_v1alpha3_Images(in *output.Images, out *Images, s
 }
 
 func autoConvert_v1alpha3_UpgradePlan_To_output_UpgradePlan(in *UpgradePlan, out *output.UpgradePlan, s conversion.Scope) error {
-	out.Components = *(*[]output.ComponentUpgradePlan)(unsafe.Pointer(&in.Components))
+	out.AvailableUpgrades = *(*[]output.AvailableUpgrade)(unsafe.Pointer(&in.AvailableUpgrades))
 	out.ConfigVersions = *(*[]output.ComponentConfigVersionState)(unsafe.Pointer(&in.ConfigVersions))
 	return nil
 }
@@ -263,12 +295,8 @@ func Convert_v1alpha3_UpgradePlan_To_output_UpgradePlan(in *UpgradePlan, out *ou
 }
 
 func autoConvert_output_UpgradePlan_To_v1alpha3_UpgradePlan(in *output.UpgradePlan, out *UpgradePlan, s conversion.Scope) error {
-	out.Components = *(*[]ComponentUpgradePlan)(unsafe.Pointer(&in.Components))
+	out.AvailableUpgrades = *(*[]AvailableUpgrade)(unsafe.Pointer(&in.AvailableUpgrades))
 	out.ConfigVersions = *(*[]ComponentConfigVersionState)(unsafe.Pointer(&in.ConfigVersions))
+	// WARNING: in.Components requires manual conversion: does not exist in peer-type
 	return nil
 }
-
-// Convert_output_UpgradePlan_To_v1alpha3_UpgradePlan is an autogenerated conversion function.
-func Convert_output_UpgradePlan_To_v1alpha3_UpgradePlan(in *output.UpgradePlan, out *UpgradePlan, s conversion.Scope) error {
-	return autoConvert_output_UpgradePlan_To_v1alpha3_UpgradePlan(in, out, s)
-}

cmd/kubeadm/app/apis/output/v1alpha3/zz_generated.deepcopy.go

@@ -25,6 +25,36 @@ import (
 	runtime "k8s.io/apimachinery/pkg/runtime"
 )
 
+// DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
+func (in *AvailableUpgrade) DeepCopyInto(out *AvailableUpgrade) {
+	*out = *in
+	out.TypeMeta = in.TypeMeta
+	if in.Components != nil {
+		in, out := &in.Components, &out.Components
+		*out = make([]ComponentUpgradePlan, len(*in))
+		copy(*out, *in)
+	}
+	return
+}
+
+// DeepCopy is an autogenerated deepcopy function, copying the receiver, creating a new AvailableUpgrade.
+func (in *AvailableUpgrade) DeepCopy() *AvailableUpgrade {
+	if in == nil {
+		return nil
+	}
+	out := new(AvailableUpgrade)
+	in.DeepCopyInto(out)
+	return out
+}
+
+// DeepCopyObject is an autogenerated deepcopy function, copying the receiver, creating a new runtime.Object.
+func (in *AvailableUpgrade) DeepCopyObject() runtime.Object {
+	if c := in.DeepCopy(); c != nil {
+		return c
+	}
+	return nil
+}
+
 // DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
 func (in *BootstrapToken) DeepCopyInto(out *BootstrapToken) {
 	*out = *in
@@ -182,10 +212,12 @@ func (in *Images) DeepCopyObject() runtime.Object {
 func (in *UpgradePlan) DeepCopyInto(out *UpgradePlan) {
 	*out = *in
 	out.TypeMeta = in.TypeMeta
-	if in.Components != nil {
+	if in.AvailableUpgrades != nil {
-		in, out := &in.Components, &out.Components
+		in, out := &in.AvailableUpgrades, &out.AvailableUpgrades
-		*out = make([]ComponentUpgradePlan, len(*in))
+		*out = make([]AvailableUpgrade, len(*in))
-		copy(*out, *in)
+		for i := range *in {
+			(*in)[i].DeepCopyInto(&(*out)[i])
+		}
 	}
 	if in.ConfigVersions != nil {
 		in, out := &in.ConfigVersions, &out.ConfigVersions

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

@@ -25,6 +25,36 @@ import (
 	runtime "k8s.io/apimachinery/pkg/runtime"
 )
 
+// DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
+func (in *AvailableUpgrade) DeepCopyInto(out *AvailableUpgrade) {
+	*out = *in
+	out.TypeMeta = in.TypeMeta
+	if in.Components != nil {
+		in, out := &in.Components, &out.Components
+		*out = make([]ComponentUpgradePlan, len(*in))
+		copy(*out, *in)
+	}
+	return
+}
+
+// DeepCopy is an autogenerated deepcopy function, copying the receiver, creating a new AvailableUpgrade.
+func (in *AvailableUpgrade) DeepCopy() *AvailableUpgrade {
+	if in == nil {
+		return nil
+	}
+	out := new(AvailableUpgrade)
+	in.DeepCopyInto(out)
+	return out
+}
+
+// DeepCopyObject is an autogenerated deepcopy function, copying the receiver, creating a new runtime.Object.
+func (in *AvailableUpgrade) DeepCopyObject() runtime.Object {
+	if c := in.DeepCopy(); c != nil {
+		return c
+	}
+	return nil
+}
+
 // DeepCopyInto is an autogenerated deepcopy function, copying the receiver, writing into out. in must be non-nil.
 func (in *BootstrapToken) DeepCopyInto(out *BootstrapToken) {
 	*out = *in
@@ -182,16 +212,23 @@ func (in *Images) DeepCopyObject() runtime.Object {
 func (in *UpgradePlan) DeepCopyInto(out *UpgradePlan) {
 	*out = *in
 	out.TypeMeta = in.TypeMeta
-	if in.Components != nil {
+	if in.AvailableUpgrades != nil {
-		in, out := &in.Components, &out.Components
+		in, out := &in.AvailableUpgrades, &out.AvailableUpgrades
-		*out = make([]ComponentUpgradePlan, len(*in))
+		*out = make([]AvailableUpgrade, len(*in))
-		copy(*out, *in)
+		for i := range *in {
+			(*in)[i].DeepCopyInto(&(*out)[i])
+		}
 	}
 	if in.ConfigVersions != nil {
 		in, out := &in.ConfigVersions, &out.ConfigVersions
 		*out = make([]ComponentConfigVersionState, len(*in))
 		copy(*out, *in)
 	}
+	if in.Components != nil {
+		in, out := &in.Components, &out.Components
+		*out = make([]ComponentUpgradePlan, len(*in))
+		copy(*out, *in)
+	}
 	return
 }
 

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

@@ -31,11 +31,10 @@ import (
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/util/version"
 	"k8s.io/cli-runtime/pkg/genericclioptions"
-	"k8s.io/cli-runtime/pkg/printers"
 	"k8s.io/klog/v2"
 
 	outputapischeme "k8s.io/kubernetes/cmd/kubeadm/app/apis/output/scheme"
-	outputapiv1alpha2 "k8s.io/kubernetes/cmd/kubeadm/app/apis/output/v1alpha2"
+	outputapiv1alpha3 "k8s.io/kubernetes/cmd/kubeadm/app/apis/output/v1alpha3"
 	cmdutil "k8s.io/kubernetes/cmd/kubeadm/app/cmd/util"
 	"k8s.io/kubernetes/cmd/kubeadm/app/componentconfigs"
 	"k8s.io/kubernetes/cmd/kubeadm/app/constants"
@@ -59,7 +58,7 @@ func newCmdPlan(apf *applyPlanFlags) *cobra.Command {
 		applyPlanFlags: apf,
 	}
 
-	outputFlags := newUpgradePlanPrintFlags(output.TextOutput)
+	outputFlags := output.NewOutputFlags(&upgradePlanTextPrintFlags{}).WithTypeSetter(outputapischeme.Scheme).WithDefaultOutput(output.TextOutput)
 
 	cmd := &cobra.Command{
 		Use:   "plan [version] [flags]",
@@ -82,174 +81,15 @@ func newCmdPlan(apf *applyPlanFlags) *cobra.Command {
 	return cmd
 }
 
-// newComponentUpgradePlan helper creates outputapiv1alpha2.ComponentUpgradePlan object
+// newComponentUpgradePlan helper creates outputapiv1alpha3.ComponentUpgradePlan object
-func newComponentUpgradePlan(name, currentVersion, newVersion string) outputapiv1alpha2.ComponentUpgradePlan {
+func newComponentUpgradePlan(name, currentVersion, newVersion string) outputapiv1alpha3.ComponentUpgradePlan {
-	return outputapiv1alpha2.ComponentUpgradePlan{
+	return outputapiv1alpha3.ComponentUpgradePlan{
 		Name:           name,
 		CurrentVersion: currentVersion,
 		NewVersion:     newVersion,
 	}
 }
 
-// upgradePlanPrintFlags defines a printer flag structure for the
-// upgrade plan kubeadm command and provides a method
-// of retrieving a known printer based on flag values provided.
-type upgradePlanPrintFlags struct {
-	// JSONYamlPrintFlags provides default flags necessary for json/yaml printing
-	JSONYamlPrintFlags *upgradePlanJSONYamlPrintFlags
-	// TextPrintFlags provides default flags necessary for text printing
-	TextPrintFlags *upgradePlanTextPrintFlags
-	// TypeSetterPrinter is an implementation of ResourcePrinter that wraps another printer with types set on the objects
-	TypeSetterPrinter *printers.TypeSetterPrinter
-	// OutputFormat contains currently set output format
-	OutputFormat string
-}
-
-func newUpgradePlanPrintFlags(outputFormat string) *upgradePlanPrintFlags {
-	return &upgradePlanPrintFlags{
-		JSONYamlPrintFlags: &upgradePlanJSONYamlPrintFlags{},
-		TextPrintFlags:     &upgradePlanTextPrintFlags{},
-		TypeSetterPrinter:  printers.NewTypeSetter(outputapischeme.Scheme),
-		OutputFormat:       strings.ToLower(outputFormat),
-	}
-}
-
-// AllowedFormats returns a list of allowed output formats
-func (pf *upgradePlanPrintFlags) AllowedFormats() []string {
-	ret := pf.TextPrintFlags.AllowedFormats()
-	return append(ret, pf.JSONYamlPrintFlags.AllowedFormats()...)
-}
-
-// AddFlags receives a *cobra.Command reference and binds
-// flags related to Kubeadm printing to it
-func (pf *upgradePlanPrintFlags) AddFlags(cmd *cobra.Command) {
-	pf.TextPrintFlags.AddFlags(cmd)
-	pf.JSONYamlPrintFlags.AddFlags(cmd)
-	// TODO: once we are confident the feature is graduated we should remove the EXPERIMENTAL text below:
-	// https://github.com/kubernetes/kubeadm/issues/494
-	cmd.Flags().StringVarP(&pf.OutputFormat, "output", "o", pf.OutputFormat, fmt.Sprintf("EXPERIMENTAL: Output format. One of: %s.", strings.Join(pf.AllowedFormats(), "|")))
-}
-
-// ToPrinter receives an outputFormat and returns a printer capable of
-// handling format printing.
-// Returns error if the specified outputFormat does not match supported formats.
-func (pf *upgradePlanPrintFlags) ToPrinter() (output.Printer, error) {
-	switch pf.OutputFormat {
-	case output.TextOutput:
-		return pf.TextPrintFlags.ToPrinter(pf.OutputFormat)
-	case output.JSONOutput:
-		return newUpgradePlanJSONYAMLPrinter(pf.TypeSetterPrinter.WrapToPrinter(pf.JSONYamlPrintFlags.ToPrinter(output.JSONOutput)))
-	case output.YAMLOutput:
-		return newUpgradePlanJSONYAMLPrinter(pf.TypeSetterPrinter.WrapToPrinter(pf.JSONYamlPrintFlags.ToPrinter(output.YAMLOutput)))
-	default:
-		return nil, genericclioptions.NoCompatiblePrinterError{OutputFormat: &pf.OutputFormat, AllowedFormats: pf.AllowedFormats()}
-	}
-}
-
-type upgradePlanJSONYamlPrintFlags struct {
-	genericclioptions.JSONYamlPrintFlags
-}
-
-// AllowedFormats returns a list of allowed output formats
-func (pf *upgradePlanJSONYamlPrintFlags) AllowedFormats() []string {
-	return []string{output.JSONOutput, output.YAMLOutput}
-}
-
-// upgradePlanJSONYAMLPrinter prints upgrade plan in a JSON or YAML format
-type upgradePlanJSONYAMLPrinter struct {
-	output.ResourcePrinterWrapper
-	Components     []outputapiv1alpha2.ComponentUpgradePlan
-	ConfigVersions []outputapiv1alpha2.ComponentConfigVersionState
-}
-
-// newUpgradePlanJSONYAMLPrinter creates a new upgradePlanJSONYAMLPrinter object
-func newUpgradePlanJSONYAMLPrinter(resourcePrinter printers.ResourcePrinter, err error) (output.Printer, error) {
-	if err != nil {
-		return nil, err
-	}
-	return &upgradePlanJSONYAMLPrinter{ResourcePrinterWrapper: output.ResourcePrinterWrapper{Printer: resourcePrinter}}, nil
-}
-
-// PrintObj is an implementation of ResourcePrinter.PrintObj that adds object to the buffer
-func (p *upgradePlanJSONYAMLPrinter) PrintObj(obj runtime.Object, writer io.Writer) error {
-	item, ok := obj.(*outputapiv1alpha2.ComponentUpgradePlan)
-	if !ok {
-		return errors.Errorf("expected ComponentUpgradePlan, but got %+v", obj)
-	}
-	p.Components = append(p.Components, *item)
-	return nil
-}
-
-// Flush writes any buffered data once last object is added
-func (p *upgradePlanJSONYAMLPrinter) Flush(writer io.Writer, last bool) {
-	if !last {
-		return
-	}
-	if len(p.Components) == 0 && len(p.ConfigVersions) == 0 {
-		return
-	}
-	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 does nothing.
-func (p *upgradePlanJSONYAMLPrinter) Close(writer io.Writer) {}
-
-// upgradePlanTextPrinter prints upgrade plan in a text form
-type upgradePlanTextPrinter struct {
-	output.TextPrinter
-	columns   []string
-	tabwriter *tabwriter.Writer
-}
-
-// Flush writes any buffered data
-func (p *upgradePlanTextPrinter) Flush(writer io.Writer, last bool) {
-	if p.tabwriter != nil {
-		p.tabwriter.Flush()
-		p.tabwriter = nil
-		p.Fprintln(writer, "")
-	}
-}
-
-// PrintObj is an implementation of ResourcePrinter.PrintObj for upgrade plan plain text output
-func (p *upgradePlanTextPrinter) PrintObj(obj runtime.Object, writer io.Writer) error {
-	if p.tabwriter == nil {
-		p.tabwriter = tabwriter.NewWriter(writer, 10, 4, 3, ' ', 0)
-		// Print header
-		fmt.Fprintln(p.tabwriter, strings.Join(p.columns, "\t"))
-	}
-
-	item, ok := obj.(*outputapiv1alpha2.ComponentUpgradePlan)
-	if !ok {
-		return errors.Errorf("expected ComponentUpgradePlan, but got %+v", obj)
-	}
-
-	// Print item
-	fmt.Fprintf(p.tabwriter, "%s\t%s\t%s\n", item.Name, item.CurrentVersion, item.NewVersion)
-	return nil
-}
-
-// upgradePlanTextPrintFlags provides flags necessary for printing upgrade plan in a text form
-type upgradePlanTextPrintFlags struct{}
-
-func (pf *upgradePlanTextPrintFlags) AddFlags(cmd *cobra.Command) {}
-
-// AllowedFormats returns a list of allowed output formats
-func (pf *upgradePlanTextPrintFlags) AllowedFormats() []string {
-	return []string{output.TextOutput}
-}
-
-// ToPrinter returns a 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", "TARGET"}}, nil
-	}
-	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
 func runPlan(flags *planFlags, args []string, printer output.Printer) error {
 	// Start with the basics, verify that the cluster is healthy, build a client and a versionGetter. Never dry-run when planning.
@@ -284,34 +124,24 @@ func runPlan(flags *planFlags, args []string, printer output.Printer) error {
 		return nil
 	}
 
-	// A workaround to set the configVersionStates in the printer
+	// Generate and print the upgrade plan
-	if p, ok := printer.(*upgradePlanJSONYAMLPrinter); ok {
+	plan := genUpgradePlan(availUpgrades, configVersionStates, isExternalEtcd)
-		p.ConfigVersions = configVersionStates
+	return printer.PrintObj(plan, os.Stdout)
-	}
+}
 
-	// Generate and print upgrade plans
+// genUpgradePlan generates upgrade plan from available upgrades and component config version states
+func genUpgradePlan(availUpgrades []upgrade.Upgrade, configVersions []outputapiv1alpha3.ComponentConfigVersionState, isExternalEtcd bool) *outputapiv1alpha3.UpgradePlan {
+	plan := &outputapiv1alpha3.UpgradePlan{ConfigVersions: configVersions}
 	for _, up := range availUpgrades {
-		plan, unstableVersionFlag, err := genUpgradePlan(&up, isExternalEtcd)
+		au := genAvailableUpgrade(&up, isExternalEtcd)
-		if err != nil {
+		plan.AvailableUpgrades = append(plan.AvailableUpgrades, au)
-			return err
-		}
-
-		// Actually, this is needed for machine-readable output only.
-		// printUpgradePlan won't output the configVersionStates as it will simply print the same table several times
-		// in the human-readable output if it did so
-		plan.ConfigVersions = configVersionStates
-
-		printUpgradePlan(&up, plan, unstableVersionFlag, isExternalEtcd, os.Stdout, printer)
 	}
-
+	return plan
-	// Finally, print the component config state table
-	printComponentConfigVersionStates(configVersionStates, os.Stdout, printer)
-	return nil
 }
 
 // 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 []outputapiv1alpha2.ComponentUpgradePlan, up *upgrade.Upgrade, name string) []outputapiv1alpha2.ComponentUpgradePlan {
+func appendDNSComponent(components []outputapiv1alpha3.ComponentUpgradePlan, up *upgrade.Upgrade, name string) []outputapiv1alpha3.ComponentUpgradePlan {
 	beforeVersion := up.Before.DNSVersion
 	afterVersion := up.After.DNSVersion
 
@@ -321,23 +151,20 @@ func appendDNSComponent(components []outputapiv1alpha2.ComponentUpgradePlan, up
 	return components
 }
 
-// genUpgradePlan generates output-friendly upgrade plan out of upgrade.Upgrade structure
+// appendKubeadmComponent appends kubeadm component to the list of components
-func genUpgradePlan(up *upgrade.Upgrade, isExternalEtcd bool) (*outputapiv1alpha2.UpgradePlan, string, error) {
+func appendKubeadmComponent(components []outputapiv1alpha3.ComponentUpgradePlan, up *upgrade.Upgrade, name string) []outputapiv1alpha3.ComponentUpgradePlan {
-	newK8sVersion, err := version.ParseSemantic(up.After.KubeVersion)
+	beforeVersion := up.Before.KubeadmVersion
-	if err != nil {
+	afterVersion := up.After.KubeadmVersion
-		return nil, "", errors.Wrapf(err, "Unable to parse normalized version %q as a semantic version", up.After.KubeVersion)
-	}
 
-	unstableVersionFlag := ""
+	if beforeVersion != "" || afterVersion != "" {
-	if len(newK8sVersion.PreRelease()) != 0 {
+		components = append(components, newComponentUpgradePlan(name, beforeVersion, afterVersion))
-		if strings.HasPrefix(newK8sVersion.PreRelease(), "rc") {
-			unstableVersionFlag = " --allow-release-candidate-upgrades"
-		} else {
-			unstableVersionFlag = " --allow-experimental-upgrades"
-		}
 	}
+	return components
+}
 
-	components := []outputapiv1alpha2.ComponentUpgradePlan{}
+// genAvailableUpgrade generates available upgrade from upgrade object and external etcd boolean
+func genAvailableUpgrade(up *upgrade.Upgrade, isExternalEtcd bool) outputapiv1alpha3.AvailableUpgrade {
+	components := []outputapiv1alpha3.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
@@ -354,59 +181,13 @@ func genUpgradePlan(up *upgrade.Upgrade, isExternalEtcd bool) (*outputapiv1alpha
 	components = append(components, newComponentUpgradePlan(constants.KubeProxy, up.Before.KubeVersion, up.After.KubeVersion))
 
 	components = appendDNSComponent(components, up, constants.CoreDNS)
+	components = appendKubeadmComponent(components, up, constants.Kubeadm)
 
 	if !isExternalEtcd {
 		components = append(components, newComponentUpgradePlan(constants.Etcd, up.Before.EtcdVersion, up.After.EtcdVersion))
 	}
 
-	return &outputapiv1alpha2.UpgradePlan{Components: components}, unstableVersionFlag, nil
+	return outputapiv1alpha3.AvailableUpgrade{Description: up.Description, Components: components}
-}
-
-// printUpgradePlan prints a UX-friendly overview of what versions are available to upgrade to
-func printUpgradePlan(up *upgrade.Upgrade, plan *outputapiv1alpha2.UpgradePlan, unstableVersionFlag string, isExternalEtcd bool, writer io.Writer, printer output.Printer) {
-	printHeader := true
-	printManualUpgradeHeader := true
-	for _, component := range plan.Components {
-		if isExternalEtcd && component.Name == constants.Etcd {
-			// Don't print etcd if it's external
-			continue
-		} else if component.Name == constants.Kubelet {
-			if printManualUpgradeHeader {
-				printer.Fprintln(writer, "Components that must be upgraded manually after you have upgraded the control plane with 'kubeadm upgrade apply':")
-				plan := newComponentUpgradePlan(component.Name, component.CurrentVersion, component.NewVersion)
-				printer.PrintObj(&plan, writer)
-				printManualUpgradeHeader = false
-			} else {
-				plan := newComponentUpgradePlan("", component.CurrentVersion, component.NewVersion)
-				printer.PrintObj(&plan, writer)
-			}
-		} else {
-			if printHeader {
-				// End of manual upgrades table
-				printer.Flush(writer, false)
-				printer.Fprintf(writer, "Upgrade to the latest %s:\n", up.Description)
-				printer.Fprintln(writer, "")
-				printHeader = false
-			}
-			plan := newComponentUpgradePlan(component.Name, component.CurrentVersion, component.NewVersion)
-			printer.PrintObj(&plan, writer)
-		}
-	}
-
-	printer.Flush(writer, true)
-
-	printer.Fprintln(writer, "You can now apply the upgrade by executing the following command:")
-	printer.Fprintln(writer, "")
-	printer.Fprintf(writer, "\tkubeadm upgrade apply %s%s\n", up.After.KubeVersion, unstableVersionFlag)
-	printer.Fprintln(writer, "")
-
-	if up.Before.KubeadmVersion != 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(writer, "")
-	}
-
-	printLineSeparator(writer, printer)
-	printer.Close(writer)
 }
 
 // sortedSliceFromStringIntMap returns a slice of the keys in the map sorted alphabetically
@@ -419,6 +200,143 @@ func sortedSliceFromStringIntMap(strMap map[string]uint16) []string {
 	return strSlice
 }
 
+// upgradePlanTextPrintFlags provides flags necessary for printing upgrade plan in a text form
+type upgradePlanTextPrintFlags struct{}
+
+// ToPrinter returns a kubeadm printer for the text output format
+func (tpf *upgradePlanTextPrintFlags) ToPrinter(outputFormat string) (output.Printer, error) {
+	if outputFormat == output.TextOutput {
+		return &upgradePlanTextPrinter{}, nil
+	}
+	return nil, genericclioptions.NoCompatiblePrinterError{OutputFormat: &outputFormat, AllowedFormats: []string{output.TextOutput}}
+}
+
+// upgradePlanTextPrinter prints upgrade plan in a text form
+type upgradePlanTextPrinter struct {
+	output.TextPrinter
+}
+
+// PrintObj is an implementation of ResourcePrinter.PrintObj for upgrade plan plain text output
+func (printer *upgradePlanTextPrinter) PrintObj(obj runtime.Object, writer io.Writer) error {
+	plan, ok := obj.(*outputapiv1alpha3.UpgradePlan)
+	if !ok {
+		return errors.Errorf("expected UpgradePlan, but got %+v", obj)
+	}
+
+	for _, au := range plan.AvailableUpgrades {
+		if err := printer.printAvailableUpgrade(writer, &au); err != nil {
+			return err
+		}
+	}
+	printer.printComponentConfigVersionStates(writer, plan.ConfigVersions)
+	return nil
+}
+
+// printUpgradePlan prints a UX-friendly overview of what versions are available to upgrade to
+func (printer *upgradePlanTextPrinter) printAvailableUpgrade(writer io.Writer, au *outputapiv1alpha3.AvailableUpgrade) error {
+	var kubeVersion string
+	var beforeKubeadmVersion, afterKubeadmVersion string
+	for _, component := range au.Components {
+		if component.Name == constants.KubeAPIServer {
+			kubeVersion = component.NewVersion
+		}
+		if component.Name == constants.Kubeadm {
+			beforeKubeadmVersion = component.CurrentVersion
+			afterKubeadmVersion = component.NewVersion
+		}
+	}
+
+	newK8sVersion, err := version.ParseSemantic(kubeVersion)
+	if err != nil {
+		return errors.Wrapf(err, "Unable to parse normalized version %q as a semantic version", kubeVersion)
+	}
+
+	unstableVersionFlag := ""
+	if len(newK8sVersion.PreRelease()) != 0 {
+		if strings.HasPrefix(newK8sVersion.PreRelease(), "rc") {
+			unstableVersionFlag = " --allow-release-candidate-upgrades"
+		} else {
+			unstableVersionFlag = " --allow-experimental-upgrades"
+		}
+	}
+
+	_, _ = printer.Fprintln(writer, "Components that must be upgraded manually after you have upgraded the control plane with 'kubeadm upgrade apply':")
+	tabw := tabwriter.NewWriter(writer, 10, 4, 3, ' ', 0)
+	_, _ = printer.Fprintln(tabw, strings.Join([]string{"COMPONENT", "CURRENT", "TARGET"}, "\t"))
+	for i, component := range au.Components {
+		if component.Name != constants.Kubelet {
+			continue
+		}
+		if i == 0 {
+			_, _ = printer.Fprintf(tabw, "%s\t%s\t%s\n", component.Name, component.CurrentVersion, component.NewVersion)
+		} else {
+			_, _ = printer.Fprintf(tabw, "%s\t%s\t%s\n", "", component.CurrentVersion, component.NewVersion)
+		}
+	}
+	_ = tabw.Flush()
+
+	_, _ = printer.Fprintln(writer, "")
+	_, _ = printer.Fprintf(writer, "Upgrade to the latest %s:\n", au.Description)
+	_, _ = printer.Fprintln(writer, "")
+	_, _ = printer.Fprintln(tabw, strings.Join([]string{"COMPONENT", "CURRENT", "TARGET"}, "\t"))
+	for _, component := range au.Components {
+		if component.Name == constants.Kubelet || component.Name == constants.Kubeadm {
+			continue
+		}
+		_, _ = printer.Fprintf(tabw, "%s\t%s\t%s\n", component.Name, component.CurrentVersion, component.NewVersion)
+	}
+	_ = tabw.Flush()
+
+	_, _ = printer.Fprintln(writer, "")
+	_, _ = printer.Fprintln(writer, "You can now apply the upgrade by executing the following command:")
+	_, _ = printer.Fprintln(writer, "")
+	_, _ = printer.Fprintf(writer, "\tkubeadm upgrade apply %s%s\n", kubeVersion, unstableVersionFlag)
+	_, _ = printer.Fprintln(writer, "")
+
+	if beforeKubeadmVersion != afterKubeadmVersion {
+		_, _ = printer.Fprintf(writer, "Note: Before you can perform this upgrade, you have to update kubeadm to %s.\n", afterKubeadmVersion)
+		_, _ = printer.Fprintln(writer, "")
+	}
+
+	printer.printLineSeparator(writer)
+	return nil
+}
+
+// printComponentConfigVersionStates prints a UX-friendly overview of the current state of component configs
+func (printer *upgradePlanTextPrinter) printComponentConfigVersionStates(w io.Writer, versionStates []outputapiv1alpha3.ComponentConfigVersionState) {
+	if len(versionStates) == 0 {
+		_, _ = printer.Fprintln(w, "No information available on component configs.")
+		return
+	}
+
+	_, _ = printer.Fprintln(w, dedent.Dedent(`
+		The table below shows the current state of component configs as understood by this version of kubeadm.
+		Configs that have a "yes" mark in the "MANUAL UPGRADE REQUIRED" column require manual config upgrade or
+		resetting to kubeadm defaults before a successful upgrade can be performed. The version to manually
+		upgrade to is denoted in the "PREFERRED VERSION" column.
+	`))
+
+	tabw := tabwriter.NewWriter(w, 10, 4, 3, ' ', 0)
+	_, _ = printer.Fprintln(tabw, strings.Join([]string{"API GROUP", "CURRENT VERSION", "PREFERRED VERSION", "MANUAL UPGRADE REQUIRED"}, "\t"))
+
+	for _, state := range versionStates {
+		_, _ = printer.Fprintf(tabw,
+			"%s\t%s\t%s\t%s\n",
+			state.Group,
+			strOrDash(state.CurrentVersion),
+			strOrDash(state.PreferredVersion),
+			yesOrNo(state.ManualUpgradeRequired),
+		)
+	}
+
+	_ = tabw.Flush()
+	printer.printLineSeparator(w)
+}
+
+func (printer *upgradePlanTextPrinter) printLineSeparator(w io.Writer) {
+	_, _ = printer.Fprintf(w, "_____________________________________________________________________\n\n")
+}
+
 func strOrDash(s string) string {
 	if s != "" {
 		return s
@@ -432,37 +350,3 @@ func yesOrNo(b bool) string {
 	}
 	return "no"
 }
-
-func printLineSeparator(w io.Writer, printer output.Printer) {
-	printer.Fprintf(w, "_____________________________________________________________________\n\n")
-}
-
-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
-	}
-
-	printer.Fprintln(w, dedent.Dedent(`
-		The table below shows the current state of component configs as understood by this version of kubeadm.
-		Configs that have a "yes" mark in the "MANUAL UPGRADE REQUIRED" column require manual config upgrade or
-		resetting to kubeadm defaults before a successful upgrade can be performed. The version to manually
-		upgrade to is denoted in the "PREFERRED VERSION" column.
-	`))
-
-	tabw := tabwriter.NewWriter(w, 10, 4, 3, ' ', 0)
-	printer.Fprintln(tabw, "API GROUP\tCURRENT VERSION\tPREFERRED VERSION\tMANUAL UPGRADE REQUIRED")
-
-	for _, state := range versionStates {
-		printer.Fprintf(tabw,
-			"%s\t%s\t%s\t%s\n",
-			state.Group,
-			strOrDash(state.CurrentVersion),
-			strOrDash(state.PreferredVersion),
-			yesOrNo(state.ManualUpgradeRequired),
-		)
-	}
-
-	tabw.Flush()
-	printLineSeparator(w, printer)
-}

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

@@ -21,6 +21,9 @@ import (
 	"reflect"
 	"testing"
 
+	"k8s.io/apimachinery/pkg/util/diff"
+	outputapischeme "k8s.io/kubernetes/cmd/kubeadm/app/apis/output/scheme"
+	outputapiv1alpha3 "k8s.io/kubernetes/cmd/kubeadm/app/apis/output/v1alpha3"
 	"k8s.io/kubernetes/cmd/kubeadm/app/phases/upgrade"
 	"k8s.io/kubernetes/cmd/kubeadm/app/util/output"
 )
@@ -67,10 +70,26 @@ func TestSortedSliceFromStringIntMap(t *testing.T) {
 }
 
 // TODO Think about modifying this test to be less verbose checking b/c it can be brittle.
-func TestPrintAvailableUpgrades(t *testing.T) {
+func TestPrintUpgradePlan(t *testing.T) {
+	versionStates := []outputapiv1alpha3.ComponentConfigVersionState{
+		{
+			Group:                 "kubeproxy.config.k8s.io",
+			CurrentVersion:        "v1alpha1",
+			PreferredVersion:      "v1alpha1",
+			ManualUpgradeRequired: false,
+		},
+		{
+			Group:                 "kubelet.config.k8s.io",
+			CurrentVersion:        "v1beta1",
+			PreferredVersion:      "v1beta1",
+			ManualUpgradeRequired: false,
+		},
+	}
+
 	var tests = []struct {
 		name          string
 		upgrades      []upgrade.Upgrade
+		versionStates []outputapiv1alpha3.ComponentConfigVersionState
 		buf           *bytes.Buffer
 		expectedBytes []byte
 		externalEtcd  bool
@@ -97,6 +116,7 @@ func TestPrintAvailableUpgrades(t *testing.T) {
 					},
 				},
 			},
+			versionStates: versionStates,
 			expectedBytes: []byte(`Components that must be upgraded manually after you have upgraded the control plane with 'kubeadm upgrade apply':
 COMPONENT   CURRENT       TARGET
 kubelet     1 x v1.18.1   v1.18.4
@@ -119,6 +139,17 @@ Note: Before you can perform this upgrade, you have to update kubeadm to v1.18.4
 
 _____________________________________________________________________
 
+
+The table below shows the current state of component configs as understood by this version of kubeadm.
+Configs that have a "yes" mark in the "MANUAL UPGRADE REQUIRED" column require manual config upgrade or
+resetting to kubeadm defaults before a successful upgrade can be performed. The version to manually
+upgrade to is denoted in the "PREFERRED VERSION" column.
+
+API GROUP                 CURRENT VERSION   PREFERRED VERSION   MANUAL UPGRADE REQUIRED
+kubeproxy.config.k8s.io   v1alpha1          v1alpha1            no
+kubelet.config.k8s.io     v1beta1           v1beta1             no
+_____________________________________________________________________
+
 `),
 		},
 		{
@@ -143,6 +174,7 @@ _____________________________________________________________________
 					},
 				},
 			},
+			versionStates: versionStates,
 			expectedBytes: []byte(`Components that must be upgraded manually after you have upgraded the control plane with 'kubeadm upgrade apply':
 COMPONENT   CURRENT       TARGET
 kubelet     1 x v1.18.4   v1.19.0
@@ -165,6 +197,17 @@ Note: Before you can perform this upgrade, you have to update kubeadm to v1.19.0
 
 _____________________________________________________________________
 
+
+The table below shows the current state of component configs as understood by this version of kubeadm.
+Configs that have a "yes" mark in the "MANUAL UPGRADE REQUIRED" column require manual config upgrade or
+resetting to kubeadm defaults before a successful upgrade can be performed. The version to manually
+upgrade to is denoted in the "PREFERRED VERSION" column.
+
+API GROUP                 CURRENT VERSION   PREFERRED VERSION   MANUAL UPGRADE REQUIRED
+kubeproxy.config.k8s.io   v1alpha1          v1alpha1            no
+kubelet.config.k8s.io     v1beta1           v1beta1             no
+_____________________________________________________________________
+
 `),
 		},
 		{
@@ -207,6 +250,7 @@ _____________________________________________________________________
 					},
 				},
 			},
+			versionStates: versionStates,
 			expectedBytes: []byte(`Components that must be upgraded manually after you have upgraded the control plane with 'kubeadm upgrade apply':
 COMPONENT   CURRENT       TARGET
 kubelet     1 x v1.18.3   v1.18.5
@@ -249,6 +293,17 @@ Note: Before you can perform this upgrade, you have to update kubeadm to v1.19.0
 
 _____________________________________________________________________
 
+
+The table below shows the current state of component configs as understood by this version of kubeadm.
+Configs that have a "yes" mark in the "MANUAL UPGRADE REQUIRED" column require manual config upgrade or
+resetting to kubeadm defaults before a successful upgrade can be performed. The version to manually
+upgrade to is denoted in the "PREFERRED VERSION" column.
+
+API GROUP                 CURRENT VERSION   PREFERRED VERSION   MANUAL UPGRADE REQUIRED
+kubeproxy.config.k8s.io   v1alpha1          v1alpha1            no
+kubelet.config.k8s.io     v1beta1           v1beta1             no
+_____________________________________________________________________
+
 `),
 		},
 		{
@@ -273,6 +328,7 @@ _____________________________________________________________________
 					},
 				},
 			},
+			versionStates: versionStates,
 			expectedBytes: []byte(`Components that must be upgraded manually after you have upgraded the control plane with 'kubeadm upgrade apply':
 COMPONENT   CURRENT       TARGET
 kubelet     1 x v1.18.5   v1.19.0-beta.1
@@ -295,6 +351,17 @@ Note: Before you can perform this upgrade, you have to update kubeadm to v1.19.0
 
 _____________________________________________________________________
 
+
+The table below shows the current state of component configs as understood by this version of kubeadm.
+Configs that have a "yes" mark in the "MANUAL UPGRADE REQUIRED" column require manual config upgrade or
+resetting to kubeadm defaults before a successful upgrade can be performed. The version to manually
+upgrade to is denoted in the "PREFERRED VERSION" column.
+
+API GROUP                 CURRENT VERSION   PREFERRED VERSION   MANUAL UPGRADE REQUIRED
+kubeproxy.config.k8s.io   v1alpha1          v1alpha1            no
+kubelet.config.k8s.io     v1beta1           v1beta1             no
+_____________________________________________________________________
+
 `),
 		},
 		{
@@ -319,6 +386,7 @@ _____________________________________________________________________
 					},
 				},
 			},
+			versionStates: versionStates,
 			expectedBytes: []byte(`Components that must be upgraded manually after you have upgraded the control plane with 'kubeadm upgrade apply':
 COMPONENT   CURRENT       TARGET
 kubelet     1 x v1.18.5   v1.19.0-rc.1
@@ -341,6 +409,17 @@ Note: Before you can perform this upgrade, you have to update kubeadm to v1.19.0
 
 _____________________________________________________________________
 
+
+The table below shows the current state of component configs as understood by this version of kubeadm.
+Configs that have a "yes" mark in the "MANUAL UPGRADE REQUIRED" column require manual config upgrade or
+resetting to kubeadm defaults before a successful upgrade can be performed. The version to manually
+upgrade to is denoted in the "PREFERRED VERSION" column.
+
+API GROUP                 CURRENT VERSION   PREFERRED VERSION   MANUAL UPGRADE REQUIRED
+kubeproxy.config.k8s.io   v1alpha1          v1alpha1            no
+kubelet.config.k8s.io     v1beta1           v1beta1             no
+_____________________________________________________________________
+
 `),
 		},
 		{
@@ -366,6 +445,7 @@ _____________________________________________________________________
 					},
 				},
 			},
+			versionStates: versionStates,
 			expectedBytes: []byte(`Components that must be upgraded manually after you have upgraded the control plane with 'kubeadm upgrade apply':
 COMPONENT   CURRENT       TARGET
 kubelet     1 x v1.19.2   v1.19.3
@@ -389,6 +469,17 @@ Note: Before you can perform this upgrade, you have to update kubeadm to v1.19.3
 
 _____________________________________________________________________
 
+
+The table below shows the current state of component configs as understood by this version of kubeadm.
+Configs that have a "yes" mark in the "MANUAL UPGRADE REQUIRED" column require manual config upgrade or
+resetting to kubeadm defaults before a successful upgrade can be performed. The version to manually
+upgrade to is denoted in the "PREFERRED VERSION" column.
+
+API GROUP                 CURRENT VERSION   PREFERRED VERSION   MANUAL UPGRADE REQUIRED
+kubeproxy.config.k8s.io   v1alpha1          v1alpha1            no
+kubelet.config.k8s.io     v1beta1           v1beta1             no
+_____________________________________________________________________
+
 `),
 		},
 
@@ -414,7 +505,8 @@ _____________________________________________________________________
 					},
 				},
 			},
-			externalEtcd: true,
+			versionStates: versionStates,
+			externalEtcd:  true,
 			expectedBytes: []byte(`Components that must be upgraded manually after you have upgraded the control plane with 'kubeadm upgrade apply':
 COMPONENT   CURRENT       TARGET
 kubelet     1 x v1.19.2   v1.19.3
@@ -436,30 +528,38 @@ Note: Before you can perform this upgrade, you have to update kubeadm to v1.19.3
 
 _____________________________________________________________________
 
+
+The table below shows the current state of component configs as understood by this version of kubeadm.
+Configs that have a "yes" mark in the "MANUAL UPGRADE REQUIRED" column require manual config upgrade or
+resetting to kubeadm defaults before a successful upgrade can be performed. The version to manually
+upgrade to is denoted in the "PREFERRED VERSION" column.
+
+API GROUP                 CURRENT VERSION   PREFERRED VERSION   MANUAL UPGRADE REQUIRED
+kubeproxy.config.k8s.io   v1alpha1          v1alpha1            no
+kubelet.config.k8s.io     v1beta1           v1beta1             no
+_____________________________________________________________________
+
 `),
 		},
 	}
 	for _, rt := range tests {
 		t.Run(rt.name, func(t *testing.T) {
 			rt.buf = bytes.NewBufferString("")
-			outputFlags := newUpgradePlanPrintFlags(output.TextOutput)
+			outputFlags := output.NewOutputFlags(&upgradePlanTextPrintFlags{}).WithTypeSetter(outputapischeme.Scheme).WithDefaultOutput(output.TextOutput)
 			printer, err := outputFlags.ToPrinter()
 			if err != nil {
 				t.Errorf("failed ToPrinter, err: %+v", err)
 			}
 
-			// Generate and print upgrade plans
+			plan := genUpgradePlan(rt.upgrades, rt.versionStates, rt.externalEtcd)
-			for _, up := range rt.upgrades {
+			if err := printer.PrintObj(plan, rt.buf); err != nil {
-				plan, unstableVersionFlag, err := genUpgradePlan(&up, rt.externalEtcd)
+				t.Errorf("unexpected error when print object: %v", err)
-				if err != nil {
-					t.Errorf("failed genUpgradePlan, err: %+v", err)
-				}
-				printUpgradePlan(&up, plan, unstableVersionFlag, rt.externalEtcd, rt.buf, printer)
 			}
+
 			actualBytes := rt.buf.Bytes()
 			if !bytes.Equal(actualBytes, rt.expectedBytes) {
 				t.Errorf(
-					"failed PrintAvailableUpgrades:\n\texpected: %q\n\n\tactual  : %q",
+					"failed PrintUpgradePlan:\n\texpected: %q\n\n\tactual  : %q",
 					string(rt.expectedBytes),
 					string(actualBytes),
 				)
@@ -468,7 +568,7 @@ _____________________________________________________________________
 	}
 }
 
-func TestPrintAvailableUpgradesStructured(t *testing.T) {
+func TestPrintUpgradePlanStructured(t *testing.T) {
 	upgrades := []upgrade.Upgrade{
 		{
 			Description: "version in the v1.8 series",
@@ -490,6 +590,21 @@ func TestPrintAvailableUpgradesStructured(t *testing.T) {
 		},
 	}
 
+	versionStates := []outputapiv1alpha3.ComponentConfigVersionState{
+		{
+			Group:                 "kubeproxy.config.k8s.io",
+			CurrentVersion:        "v1alpha1",
+			PreferredVersion:      "v1alpha1",
+			ManualUpgradeRequired: false,
+		},
+		{
+			Group:                 "kubelet.config.k8s.io",
+			CurrentVersion:        "v1beta1",
+			PreferredVersion:      "v1beta1",
+			ManualUpgradeRequired: false,
+		},
+	}
+
 	var tests = []struct {
 		name         string
 		outputFormat string
@@ -502,81 +617,117 @@ func TestPrintAvailableUpgradesStructured(t *testing.T) {
 			outputFormat: "json",
 			expected: `{
     "kind": "UpgradePlan",
-    "apiVersion": "output.kubeadm.k8s.io/v1alpha2",
+    "apiVersion": "output.kubeadm.k8s.io/v1alpha3",
-    "components": [
+    "availableUpgrades": [
         {
-            "name": "kubelet",
+            "description": "version in the v1.8 series",
-            "currentVersion": "1 x v1.8.1",
+            "components": [
-            "newVersion": "v1.8.3"
+                {
-        },
+                    "name": "kubelet",
-        {
+                    "currentVersion": "1 x v1.8.1",
-            "name": "kube-apiserver",
+                    "newVersion": "v1.8.3"
-            "currentVersion": "v1.8.1",
+                },
-            "newVersion": "v1.8.3"
+                {
-        },
+                    "name": "kube-apiserver",
-        {
+                    "currentVersion": "v1.8.1",
-            "name": "kube-controller-manager",
+                    "newVersion": "v1.8.3"
-            "currentVersion": "v1.8.1",
+                },
-            "newVersion": "v1.8.3"
+                {
-        },
+                    "name": "kube-controller-manager",
-        {
+                    "currentVersion": "v1.8.1",
-            "name": "kube-scheduler",
+                    "newVersion": "v1.8.3"
-            "currentVersion": "v1.8.1",
+                },
-            "newVersion": "v1.8.3"
+                {
-        },
+                    "name": "kube-scheduler",
-        {
+                    "currentVersion": "v1.8.1",
-            "name": "kube-proxy",
+                    "newVersion": "v1.8.3"
-            "currentVersion": "v1.8.1",
+                },
-            "newVersion": "v1.8.3"
+                {
-        },
+                    "name": "kube-proxy",
-        {
+                    "currentVersion": "v1.8.1",
-            "name": "CoreDNS",
+                    "newVersion": "v1.8.3"
-            "currentVersion": "1.14.5",
+                },
-            "newVersion": "1.14.5"
+                {
-        },
+                    "name": "CoreDNS",
-        {
+                    "currentVersion": "1.14.5",
-            "name": "etcd",
+                    "newVersion": "1.14.5"
-            "currentVersion": "3.0.17",
+                },
-            "newVersion": "3.0.17"
+                {
+                    "name": "kubeadm",
+                    "currentVersion": "v1.8.2",
+                    "newVersion": "v1.8.3"
+                },
+                {
+                    "name": "etcd",
+                    "currentVersion": "3.0.17",
+                    "newVersion": "3.0.17"
+                }
+            ]
         }
     ],
-    "configVersions": null
+    "configVersions": [
+        {
+            "group": "kubeproxy.config.k8s.io",
+            "currentVersion": "v1alpha1",
+            "preferredVersion": "v1alpha1",
+            "manualUpgradeRequired": false
+        },
+        {
+            "group": "kubelet.config.k8s.io",
+            "currentVersion": "v1beta1",
+            "preferredVersion": "v1beta1",
+            "manualUpgradeRequired": false
+        }
+    ]
 }
 `,
 		},
 		{
 			name:         "YAML output",
 			outputFormat: "yaml",
-			expected: `apiVersion: output.kubeadm.k8s.io/v1alpha2
+			expected: `apiVersion: output.kubeadm.k8s.io/v1alpha3
-components:
+availableUpgrades:
-- currentVersion: 1 x v1.8.1
+- components:
-  name: kubelet
+  - currentVersion: 1 x v1.8.1
-  newVersion: v1.8.3
+    name: kubelet
-- currentVersion: v1.8.1
+    newVersion: v1.8.3
-  name: kube-apiserver
+  - currentVersion: 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-controller-manager
-- currentVersion: v1.8.1
+    newVersion: v1.8.3
-  name: kube-scheduler
+  - 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: kube-proxy
-- currentVersion: 1.14.5
+    newVersion: v1.8.3
-  name: CoreDNS
+  - currentVersion: 1.14.5
-  newVersion: 1.14.5
+    name: CoreDNS
-- currentVersion: 3.0.17
+    newVersion: 1.14.5
-  name: etcd
+  - currentVersion: v1.8.2
-  newVersion: 3.0.17
+    name: kubeadm
-configVersions: null
+    newVersion: v1.8.3
+  - currentVersion: 3.0.17
+    name: etcd
+    newVersion: 3.0.17
+  description: version in the v1.8 series
+configVersions:
+- currentVersion: v1alpha1
+  group: kubeproxy.config.k8s.io
+  manualUpgradeRequired: false
+  preferredVersion: v1alpha1
+- currentVersion: v1beta1
+  group: kubelet.config.k8s.io
+  manualUpgradeRequired: false
+  preferredVersion: v1beta1
 kind: UpgradePlan
 `,
 		},
 		{
 			name:         "Text output",
-			outputFormat: "Text",
+			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
@@ -599,6 +750,17 @@ Note: Before you can perform this upgrade, you have to update kubeadm to v1.8.3.
 
 _____________________________________________________________________
 
+
+The table below shows the current state of component configs as understood by this version of kubeadm.
+Configs that have a "yes" mark in the "MANUAL UPGRADE REQUIRED" column require manual config upgrade or
+resetting to kubeadm defaults before a successful upgrade can be performed. The version to manually
+upgrade to is denoted in the "PREFERRED VERSION" column.
+
+API GROUP                 CURRENT VERSION   PREFERRED VERSION   MANUAL UPGRADE REQUIRED
+kubeproxy.config.k8s.io   v1alpha1          v1alpha1            no
+kubelet.config.k8s.io     v1beta1           v1beta1             no
+_____________________________________________________________________
+
 `,
 		},
 	}
@@ -606,24 +768,21 @@ _____________________________________________________________________
 	for _, rt := range tests {
 		t.Run(rt.name, func(t *testing.T) {
 			rt.buf = bytes.NewBufferString("")
-			outputFlags := newUpgradePlanPrintFlags(rt.outputFormat)
+			outputFlags := output.NewOutputFlags(&upgradePlanTextPrintFlags{}).WithTypeSetter(outputapischeme.Scheme).WithDefaultOutput(rt.outputFormat)
 			printer, err := outputFlags.ToPrinter()
 			if err != nil {
 				t.Errorf("failed ToPrinter, err: %+v", err)
 			}
 
-			// Generate and print upgrade plans
+			plan := genUpgradePlan(upgrades, versionStates, false)
-			for _, up := range upgrades {
+			if err := printer.PrintObj(plan, rt.buf); err != nil {
-				plan, unstableVersionFlag, err := genUpgradePlan(&up, rt.externalEtcd)
+				t.Errorf("unexpected error when print object: %v", err)
-				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)
+
+				t.Errorf("failed PrintUpgradePlan:\n\nexpected:\n%s\n\nactual:\n%s\n\ndiff:\n%s", rt.expected, actual, diff.StringDiff(actual, rt.expected))
 			}
 		})
 	}

cmd/kubeadm/app/componentconfigs/configset.go

@@ -28,7 +28,7 @@ import (
 	"k8s.io/klog/v2"
 
 	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
-	outputapiv1alpha2 "k8s.io/kubernetes/cmd/kubeadm/app/apis/output/v1alpha2"
+	outputapiv1alpha3 "k8s.io/kubernetes/cmd/kubeadm/app/apis/output/v1alpha3"
 	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) ([]outputapiv1alpha2.ComponentConfigVersionState, error) {
+func GetVersionStates(clusterCfg *kubeadmapi.ClusterConfiguration, client clientset.Interface) ([]outputapiv1alpha3.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()
@@ -301,12 +301,12 @@ func GetVersionStates(clusterCfg *kubeadmapi.ClusterConfiguration, client client
 		return nil, err
 	}
 
-	results := []outputapiv1alpha2.ComponentConfigVersionState{}
+	results := []outputapiv1alpha3.ComponentConfigVersionState{}
 	for _, handler := range known {
 		group := handler.GroupVersion.Group
 		if _, ok := scratchClusterCfg.ComponentConfigs[group]; ok {
 			// Normally loaded component config. No manual upgrade required on behalf of users.
-			results = append(results, outputapiv1alpha2.ComponentConfigVersionState{
+			results = append(results, outputapiv1alpha3.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
@@ -315,7 +315,7 @@ 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, outputapiv1alpha2.ComponentConfigVersionState{
+			results = append(results, outputapiv1alpha3.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"
-	outputapiv1alpha2 "k8s.io/kubernetes/cmd/kubeadm/app/apis/output/v1alpha2"
+	outputapiv1alpha3 "k8s.io/kubernetes/cmd/kubeadm/app/apis/output/v1alpha3"
 	"k8s.io/kubernetes/cmd/kubeadm/app/constants"
 	kubeadmutil "k8s.io/kubernetes/cmd/kubeadm/app/util"
 )
@@ -612,7 +612,7 @@ func TestFetchFromClusterWithLocalOverwrites(t *testing.T) {
 
 func TestGetVersionStates(t *testing.T) {
 	fakeKnownContext(func() {
-		versionStateCurrent := outputapiv1alpha2.ComponentConfigVersionState{
+		versionStateCurrent := outputapiv1alpha3.ComponentConfigVersionState{
 			Group:            kubeadmapiv1.GroupName,
 			CurrentVersion:   currentClusterConfigVersion,
 			PreferredVersion: currentClusterConfigVersion,
@@ -622,7 +622,7 @@ func TestGetVersionStates(t *testing.T) {
 			desc        string
 			obj         runtime.Object
 			expectedErr bool
-			expected    outputapiv1alpha2.ComponentConfigVersionState
+			expected    outputapiv1alpha3.ComponentConfigVersionState
 		}{
 			{
 				desc:     "appropriate cluster object",
@@ -642,7 +642,7 @@ func TestGetVersionStates(t *testing.T) {
 			{
 				desc: "old signed config",
 				obj:  testClusterConfigMap(oldFooClusterConfig, true),
-				expected: outputapiv1alpha2.ComponentConfigVersionState{
+				expected: outputapiv1alpha3.ComponentConfigVersionState{
 					Group:            kubeadmapiv1.GroupName,
 					CurrentVersion:   "", // The config is treated as if it's missing
 					PreferredVersion: currentClusterConfigVersion,

cmd/kubeadm/app/constants/constants.go

@@ -340,6 +340,8 @@ const (
 	CoreDNS = "CoreDNS"
 	// Kubelet defines variable used internally when referring to the Kubelet
 	Kubelet = "kubelet"
+	// Kubeadm defines variable used internally when referring to the kubeadm component
+	Kubeadm = "kubeadm"
 
 	// KubeCertificatesVolumeName specifies the name for the Volume that is used for injecting certificates to control plane components (can be both a hostPath volume or a projected, all-in-one volume)
 	KubeCertificatesVolumeName = "k8s-certs"

cmd/kubeadm/app/util/output/output.go

@@ -144,9 +144,6 @@ type Printer interface {
 	Fprintln(writer io.Writer, args ...interface{}) (n int, err error)
 	Printf(format string, args ...interface{}) (n int, err error)
 	Println(args ...interface{}) (n int, err error)
-
-	Flush(writer io.Writer, last bool)
-	Close(writer io.Writer)
 }
 
 // TextPrinter implements Printer interface for generic text output
@@ -179,14 +176,6 @@ func (tp *TextPrinter) Println(args ...interface{}) (n int, err error) {
 	return fmt.Println(args...)
 }
 
-// Flush writes any buffered data
-func (tp *TextPrinter) Flush(writer io.Writer, last bool) {
-}
-
-// Close flushes any buffered data and closes the printer
-func (tp *TextPrinter) Close(writer io.Writer) {
-}
-
 // ResourcePrinterWrapper wraps ResourcePrinter and implements Printer interface
 type ResourcePrinterWrapper struct {
 	Printer printers.ResourcePrinter
@@ -200,14 +189,6 @@ func NewResourcePrinterWrapper(resourcePrinter printers.ResourcePrinter, err err
 	return &ResourcePrinterWrapper{Printer: resourcePrinter}, nil
 }
 
-// Flush writes any buffered data
-func (rpw *ResourcePrinterWrapper) Flush(writer io.Writer, last bool) {
-}
-
-// Close flushes any buffered data and closes the printer
-func (rpw *ResourcePrinterWrapper) Close(writer io.Writer) {
-}
-
 // PrintObj is an implementation of ResourcePrinter.PrintObj that calls underlying printer API
 func (rpw *ResourcePrinterWrapper) PrintObj(obj runtime.Object, writer io.Writer) error {
 	return rpw.Printer.PrintObj(obj, writer)