kubeadm: use separate phase for changing the kubelet's kubeconfig on upgrade for ControlPlaneKubeletLocalMode

cmd/kubeadm/app/cmd/phases/upgrade/node/controlplane.go

@@ -24,7 +24,6 @@ import (
 
 	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/options"
 	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/phases/workflow"
-	"k8s.io/kubernetes/cmd/kubeadm/app/features"
 	"k8s.io/kubernetes/cmd/kubeadm/app/phases/upgrade"
 	"k8s.io/kubernetes/cmd/kubeadm/app/util/apiclient"
 )
@@ -83,12 +82,6 @@ func runControlPlane() func(c workflow.RunData) error {
 			return errors.Wrap(err, "failed to perform addons upgrade")
 		}
 
-		if features.Enabled(cfg.FeatureGates, features.ControlPlaneKubeletLocalMode) {
-			if err := upgrade.UpdateKubeletLocalMode(cfg, dryRun); err != nil {
-				return errors.Wrap(err, "failed to update kubelet local mode")
-			}
-		}
-
 		fmt.Println("[upgrade] The control plane instance for this node was successfully updated!")
 
 		return nil

cmd/kubeadm/app/cmd/phases/upgrade/node/kubeconfig.go

@@ -0,0 +1,73 @@
+/*
+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 node holds phases of "kubeadm upgrade node".
+package node
+
+import (
+	"fmt"
+
+	"github.com/pkg/errors"
+
+	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/options"
+	"k8s.io/kubernetes/cmd/kubeadm/app/cmd/phases/workflow"
+	"k8s.io/kubernetes/cmd/kubeadm/app/features"
+	"k8s.io/kubernetes/cmd/kubeadm/app/phases/upgrade"
+)
+
+// NewKubeconfigPhase creates a kubeadm workflow phase that implements handling of kubeconfig upgrade.
+func NewKubeconfigPhase() workflow.Phase {
+	phase := workflow.Phase{
+		Name:   "kubeconfig",
+		Short:  "Upgrade kubeconfig files for this node",
+		Run:    runKubeconfig(),
+		Hidden: true,
+		InheritFlags: []string{
+			options.DryRun,
+			options.KubeconfigPath,
+		},
+	}
+	return phase
+}
+
+func runKubeconfig() func(c workflow.RunData) error {
+	return func(c workflow.RunData) error {
+		data, ok := c.(Data)
+		if !ok {
+			return errors.New("kubeconfig phase invoked with an invalid data struct")
+		}
+
+		// if this is not a control-plane node, this phase should not be executed
+		if !data.IsControlPlaneNode() {
+			fmt.Println("[upgrade] Skipping phase. Not a control plane node.")
+			return nil
+		}
+
+		// otherwise, retrieve all the info required for kubeconfig upgrade
+		cfg := data.InitCfg()
+		dryRun := data.DryRun()
+
+		if features.Enabled(cfg.FeatureGates, features.ControlPlaneKubeletLocalMode) {
+			if err := upgrade.UpdateKubeletLocalMode(cfg, dryRun); err != nil {
+				return errors.Wrap(err, "failed to update kubelet local mode")
+			}
+		}
+
+		fmt.Println("[upgrade] The kubeconfig for this node was successfully updated!")
+
+		return nil
+	}
+}

cmd/kubeadm/app/cmd/upgrade/node.go

@@ -97,6 +97,7 @@ func newCmdNode(out io.Writer) *cobra.Command {
 	// initialize the workflow runner with the list of phases
 	nodeRunner.AppendPhase(phases.NewPreflightPhase())
 	nodeRunner.AppendPhase(phases.NewControlPlane())
+	nodeRunner.AppendPhase(phases.NewKubeconfigPhase())
 	nodeRunner.AppendPhase(phases.NewKubeletConfigPhase())
 
 	// sets the data builder function, that will be used by the runner