kubeadm upgrade plan: don't load component configs

Component configs are used by kubeadm upgrade plan at the moment. However, they
can prevent kubeadm upgrade plan from functioning if loading of an unsupported
version of a component config is attempted. For that matter it's best to just
stop loading component configs as part of the kubeadm config load process.

Signed-off-by: Rostislav M. Georgiev <rostislavg@vmware.com>

cmd/kubeadm/app/cmd/alpha/certs.go

@@ -254,7 +254,7 @@ func getInternalCfg(cfgPath string, kubeconfigPath string, cfg kubeadmapiv1beta2
 	if cfgPath == "" {
 		client, err := kubeconfigutil.ClientSetFromFile(kubeconfigPath)
 		if err == nil {
-			internalcfg, err := configutil.FetchInitConfigurationFromCluster(client, out, logPrefix, false)
+			internalcfg, err := configutil.FetchInitConfigurationFromCluster(client, out, logPrefix, false, false)
 			if err == nil {
 				fmt.Println() // add empty line to separate the FetchInitConfigurationFromCluster output from the command output
 				return internalcfg, nil

cmd/kubeadm/app/cmd/join.go

@@ -545,7 +545,7 @@ func fetchInitConfiguration(tlsBootstrapCfg *clientcmdapi.Config) (*kubeadmapi.I
 	}
 
 	// Fetches the init configuration
-	initConfiguration, err := configutil.FetchInitConfigurationFromCluster(tlsClient, os.Stdout, "preflight", true)
+	initConfiguration, err := configutil.FetchInitConfigurationFromCluster(tlsClient, os.Stdout, "preflight", true, false)
 	if err != nil {
 		return nil, errors.Wrap(err, "unable to fetch the kubeadm-config ConfigMap")
 	}

cmd/kubeadm/app/cmd/reset.go

@@ -94,7 +94,7 @@ func newResetData(cmd *cobra.Command, options *resetOptions, in io.Reader, out i
 	client, err := getClientset(options.kubeconfigPath, false)
 	if err == nil {
 		klog.V(1).Infof("[reset] Loaded client set from kubeconfig file: %s", options.kubeconfigPath)
-		cfg, err = configutil.FetchInitConfigurationFromCluster(client, out, "reset", false)
+		cfg, err = configutil.FetchInitConfigurationFromCluster(client, out, "reset", false, false)
 		if err != nil {
 			klog.Warningf("[reset] Unable to fetch the kubeadm-config ConfigMap from cluster: %v", err)
 		}

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

@@ -74,7 +74,7 @@ func enforceRequirements(flags *applyPlanFlags, args []string, dryRun bool, upgr
 			newK8sVersion = cfg.KubernetesVersion
 		}
 	} else {
-		cfg, err = configutil.FetchInitConfigurationFromCluster(client, os.Stdout, "upgrade/config", false)
+		cfg, err = configutil.FetchInitConfigurationFromCluster(client, os.Stdout, "upgrade/config", false, !upgradeApply)
 	}
 
 	if err != nil {

cmd/kubeadm/app/cmd/upgrade/diff.go

@@ -91,7 +91,7 @@ func runDiff(flags *diffFlags, args []string) error {
 		if err != nil {
 			return errors.Wrapf(err, "couldn't create a Kubernetes client from file %q", flags.kubeConfigPath)
 		}
-		cfg, err = configutil.FetchInitConfigurationFromCluster(client, flags.out, "upgrade/diff", false)
+		cfg, err = configutil.FetchInitConfigurationFromCluster(client, flags.out, "upgrade/diff", false, false)
 	}
 	if err != nil {
 		return err

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

@@ -141,7 +141,7 @@ func newNodeData(cmd *cobra.Command, args []string, options *nodeOptions) (*node
 	// 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, os.Stdout, "upgrade", !isControlPlaneNode)
+	cfg, err := configutil.FetchInitConfigurationFromCluster(client, os.Stdout, "upgrade", !isControlPlaneNode, false)
 	if err != nil {
 		return nil, errors.Wrap(err, "unable to fetch the kubeadm-config ConfigMap")
 	}

cmd/kubeadm/app/util/config/cluster.go

@@ -61,12 +61,12 @@ func (ue *unretriableError) Error() string {
 }
 
 // FetchInitConfigurationFromCluster fetches configuration from a ConfigMap in the cluster
-func FetchInitConfigurationFromCluster(client clientset.Interface, w io.Writer, logPrefix string, newControlPlane bool) (*kubeadmapi.InitConfiguration, error) {
+func FetchInitConfigurationFromCluster(client clientset.Interface, w io.Writer, logPrefix string, newControlPlane, skipComponentConfigs bool) (*kubeadmapi.InitConfiguration, error) {
 	fmt.Fprintf(w, "[%s] Reading configuration from the cluster...\n", logPrefix)
 	fmt.Fprintf(w, "[%s] FYI: You can look at this config file with 'kubectl -n %s get cm %s -oyaml'\n", logPrefix, metav1.NamespaceSystem, constants.KubeadmConfigConfigMap)
 
 	// Fetch the actual config from cluster
-	cfg, err := getInitConfigurationFromCluster(constants.KubernetesDir, client, newControlPlane)
+	cfg, err := getInitConfigurationFromCluster(constants.KubernetesDir, client, newControlPlane, skipComponentConfigs)
 	if err != nil {
 		return nil, err
 	}
@@ -80,7 +80,7 @@ func FetchInitConfigurationFromCluster(client clientset.Interface, w io.Writer,
 }
 
 // getInitConfigurationFromCluster is separate only for testing purposes, don't call it directly, use FetchInitConfigurationFromCluster instead
-func getInitConfigurationFromCluster(kubeconfigDir string, client clientset.Interface, newControlPlane bool) (*kubeadmapi.InitConfiguration, error) {
+func getInitConfigurationFromCluster(kubeconfigDir string, client clientset.Interface, newControlPlane, skipComponentConfigs bool) (*kubeadmapi.InitConfiguration, error) {
 	// Also, the config map really should be KubeadmConfigConfigMap...
 	configMap, err := apiclient.GetConfigMapWithRetry(client, metav1.NamespaceSystem, constants.KubeadmConfigConfigMap)
 	if err != nil {
@@ -99,9 +99,11 @@ func getInitConfigurationFromCluster(kubeconfigDir string, client clientset.Inte
 		return nil, errors.Wrap(err, "failed to decode cluster configuration data")
 	}
 
-	// gets the component configs from the corresponding config maps
-	if err := componentconfigs.FetchFromCluster(&initcfg.ClusterConfiguration, client); err != nil {
-		return nil, errors.Wrap(err, "failed to get component configs")
+	if !skipComponentConfigs {
+		// get the component configs from the corresponding config maps
+		if err := componentconfigs.FetchFromCluster(&initcfg.ClusterConfiguration, client); err != nil {
+			return nil, errors.Wrap(err, "failed to get component configs")
+		}
 	}
 
 	// if this isn't a new controlplane instance (e.g. in case of kubeadm upgrades)

cmd/kubeadm/app/util/config/cluster_test.go

@@ -736,7 +736,7 @@ func TestGetInitConfigurationFromCluster(t *testing.T) {
 				}
 			}
 
-			cfg, err := getInitConfigurationFromCluster(tmpdir, client, rt.newControlPlane)
+			cfg, err := getInitConfigurationFromCluster(tmpdir, client, rt.newControlPlane, false)
 			if rt.expectedError != (err != nil) {
 				t.Errorf("unexpected return err from getInitConfigurationFromCluster: %v", err)
 				return