kubeadm: add the --patches flag and deprecate --experimental-patches

The feature of "patches" in kubeadm has been in Alpha for a few
releases. It has not received major bug reports from users.
Deprecate the --experimental-patches flag and add --patches.

Both flags are allowed to be mixed with --config.

cmd/kubeadm/app/apis/kubeadm/validation/validation.go

@@ -568,6 +568,8 @@ func isAllowedFlag(flagName string) bool {
 		kubeadmcmdoptions.KubeconfigDir,
 		kubeadmcmdoptions.UploadCerts,
 		kubeadmcmdoptions.Patches,
+		// TODO: https://github.com/kubernetes/kubeadm/issues/2046 remove in 1.23
+		kubeadmcmdoptions.ExperimentalPatches,
 		"print-join-command", "rootfs", "v", "log-file")
 	if allowedFlags.Has(flagName) {
 		return true

cmd/kubeadm/app/cmd/options/constant.go

@@ -144,5 +144,9 @@ const (
 	EtcdUpgrade = "etcd-upgrade"
 
 	// Patches flag sets the folder where kubeadm component patches are stored
-	Patches = "experimental-patches"
+	Patches = "patches"
+
+	// ExperimentalPatches (DEPRECATED) is the same as Patches
+	// TODO: https://github.com/kubernetes/kubeadm/issues/2046 remove in 1.23
+	ExperimentalPatches = "experimental-patches"
 )

cmd/kubeadm/app/cmd/options/generic.go

@@ -91,12 +91,16 @@ func AddKubeadmOtherFlags(flagSet *pflag.FlagSet, rootfsPath *string) {
 
 // AddPatchesFlag adds the --patches flag to the given flagset
 func AddPatchesFlag(fs *pflag.FlagSet, patchesDir *string) {
-	fs.StringVar(patchesDir, Patches, *patchesDir, `Path to a directory that contains files named `+
+	const usage = `Path to a directory that contains files named ` +
 		`"target[suffix][+patchtype].extension". For example, ` +
 		`"kube-apiserver0+merge.yaml" or just "etcd.json". ` +
+		`"target" can be one of "kube-apiserver", "kube-controller-manager", "kube-scheduler", "etcd". ` +
 		`"patchtype" can be one of "strategic", "merge" or "json" and they match the patch formats ` +
 		`supported by kubectl. The default "patchtype" is "strategic". "extension" must be either ` +
 		`"json" or "yaml". "suffix" is an optional string that can be used to determine ` +
-		`which patches are applied first alpha-numerically.`,
+		`which patches are applied first alpha-numerically.`
-	)
+	fs.StringVar(patchesDir, Patches, *patchesDir, usage)
+	// TODO: https://github.com/kubernetes/kubeadm/issues/2046 remove in 1.23
+	fs.StringVar(patchesDir, ExperimentalPatches, *patchesDir, usage)
+	fs.MarkDeprecated(ExperimentalPatches, "This flag will be removed in a future version. Please use '--patches' instead.")
 }

cmd/kubeadm/app/cmd/phases/init/controlplane.go

@@ -101,6 +101,8 @@ func getControlPlanePhaseFlags(name string) []string {
 		options.KubernetesVersion,
 		options.ImageRepository,
 		options.Patches,
+		// TODO: https://github.com/kubernetes/kubeadm/issues/2046 remove in 1.23
+		options.ExperimentalPatches,
 		options.DryRun,
 	}
 	if name == "all" || name == kubeadmconstants.KubeAPIServer {

cmd/kubeadm/app/cmd/phases/join/controlplanejoin.go

@@ -44,6 +44,8 @@ func getControlPlaneJoinPhaseFlags(name string) []string {
 	}
 	if name == "etcd" || name == "all" {
 		flags = append(flags, options.Patches)
+		// TODO: https://github.com/kubernetes/kubeadm/issues/2046 remove in 1.23
+		flags = append(flags, options.ExperimentalPatches)
 	}
 	if name != "mark-control-plane" {
 		flags = append(flags, options.APIServerAdvertiseAddress)

cmd/kubeadm/app/cmd/phases/join/controlplaneprepare.go

@@ -79,6 +79,8 @@ func getControlPlanePreparePhaseFlags(name string) []string {
 			options.TokenStr,
 			options.CertificateKey,
 			options.Patches,
+			// TODO: https://github.com/kubernetes/kubeadm/issues/2046 remove in 1.23
+			options.ExperimentalPatches,
 		}
 	case "download-certs":
 		flags = []string{
@@ -124,6 +126,8 @@ func getControlPlanePreparePhaseFlags(name string) []string {
 			options.CfgPath,
 			options.ControlPlane,
 			options.Patches,
+			// TODO: https://github.com/kubernetes/kubeadm/issues/2046 remove in 1.23
+			options.ExperimentalPatches,
 		}
 	default:
 		flags = []string{}

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

@@ -40,6 +40,8 @@ func NewControlPlane() workflow.Phase {
 			options.CertificateRenewal,
 			options.EtcdUpgrade,
 			options.Patches,
+			// TODO: https://github.com/kubernetes/kubeadm/issues/2046 remove in 1.23
+			options.ExperimentalPatches,
 		},
 	}
 	return phase