Merge pull request kubernetes#123096 from neolit123/automated-cherry-…

…pick-of-#123077-origin-release-1.29

Automated cherry pick of kubernetes#123077: kubeadm: better checks if the node is CP during "upgrade

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

@@ -41,7 +41,6 @@ import (
 // supported by this api will be exposed as a flag.
 type nodeOptions struct {
 	kubeConfigPath        string
-	isControlPlaneNode    bool
 	etcdUpgrade           bool
 	renewCerts            bool
 	dryRun                bool
@@ -106,26 +105,11 @@ func newCmdNode(out io.Writer) *cobra.Command {
 
 // newNodeOptions returns a struct ready for being used for creating cmd kubeadm upgrade node flags.
 func newNodeOptions() *nodeOptions {
-	kubeConfigPath := constants.GetKubeletKubeConfigPath()
-
-	// isControlPlaneNode checks if a node is a control-plane node by looking up
-	// the kube-apiserver manifest file
-	isControlPlaneNode := true
-	filepath := constants.GetStaticPodFilepath(constants.KubeAPIServer, constants.GetStaticPodDirectory())
-	if _, err := os.Stat(filepath); os.IsNotExist(err) {
-		isControlPlaneNode = false
-	}
-
-	if isControlPlaneNode {
-		kubeConfigPath = constants.GetAdminKubeConfigPath()
-	}
-
 	return &nodeOptions{
-		kubeConfigPath:     kubeConfigPath,
-		isControlPlaneNode: isControlPlaneNode,
-		dryRun:             false,
-		renewCerts:         true,
-		etcdUpgrade:        true,
+		kubeConfigPath: "", // This is populated in newNodeData() on runtime
+		dryRun:         false,
+		renewCerts:     true,
+		etcdUpgrade:    true,
 	}
 }
 
@@ -141,14 +125,28 @@ func addUpgradeNodeFlags(flagSet *flag.FlagSet, nodeOptions *nodeOptions) {
 // This func takes care of validating nodeOptions passed to the command, and then it converts
 // options into the internal InitConfiguration type that is used as input all the phases in the kubeadm upgrade node workflow
 func newNodeData(cmd *cobra.Command, args []string, options *nodeOptions, out io.Writer) (*nodeData, error) {
+	// Checks if a node is a control-plane node by looking up the kube-apiserver manifest file
+	isControlPlaneNode := true
+	filepath := constants.GetStaticPodFilepath(constants.KubeAPIServer, constants.GetStaticPodDirectory())
+	if _, err := os.Stat(filepath); os.IsNotExist(err) {
+		isControlPlaneNode = false
+	}
+	if len(options.kubeConfigPath) == 0 {
+		// Update the kubeconfig path depending on whether this is a control plane node or not.
+		options.kubeConfigPath = constants.GetKubeletKubeConfigPath()
+		if isControlPlaneNode {
+			options.kubeConfigPath = constants.GetAdminKubeConfigPath()
+		}
+	}
+
 	client, err := getClient(options.kubeConfigPath, options.dryRun)
 	if err != nil {
 		return nil, errors.Wrapf(err, "couldn't create a Kubernetes client from file %q", options.kubeConfigPath)
 	}
 	// Fetches the cluster configuration
 	// NB in case of control-plane node, we are reading all the info for the node; in case of NOT control-plane node
 	//    (worker node), we are not reading local API address and the CRI socket from the node object
-	cfg, err := configutil.FetchInitConfigurationFromCluster(client, nil, "upgrade", !options.isControlPlaneNode, false)
+	cfg, err := configutil.FetchInitConfigurationFromCluster(client, nil, "upgrade", !isControlPlaneNode, false)
 	if err != nil {
 		return nil, errors.Wrap(err, "unable to fetch the kubeadm-config ConfigMap")
 	}
@@ -165,7 +163,7 @@ func newNodeData(cmd *cobra.Command, args []string, options *nodeOptions, out io
 		dryRun:                options.dryRun,
 		cfg:                   cfg,
 		client:                client,
-		isControlPlaneNode:    options.isControlPlaneNode,
+		isControlPlaneNode:    isControlPlaneNode,
 		patchesDir:            options.patchesDir,
 		ignorePreflightErrors: ignorePreflightErrorsSet,
 		kubeConfigPath:        options.kubeConfigPath,