kubeadm: deprecate v1beta3

Mark v1beta3 as deprecated by showing a warning when used
and write a note about it in the doc.go file.

cmd/kubeadm/app/apis/kubeadm/v1beta3/doc.go

@@ -22,6 +22,9 @@ limitations under the License.
 // Package v1beta3 defines the v1beta3 version of the kubeadm configuration file format.
 // This version improves on the v1beta2 format by fixing some minor issues and adding a few new fields.
 //
+// DEPRECATED: v1beta3 is deprecated in favor of v1beta4 and will be removed in a future release, 1.34 or later.
+// Please migrate.
+//
 // A list of changes since v1beta2:
 //   - The deprecated "ClusterConfiguration.useHyperKubeImage" field has been removed.
 //     Kubeadm no longer supports the hyperkube image.
@@ -280,6 +283,3 @@ limitations under the License.
 //
 // - APIEndpoint, that represents the endpoint of the instance of the API server to be eventually deployed on this node.
 package v1beta3 // import "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1beta3"
-
-//TODO: The BootstrapTokenString object should move out to either k8s.io/client-go or k8s.io/api in the future
-//(probably as part of Bootstrap Tokens going GA). It should not be staged under the kubeadm API as it is now.

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

@@ -83,11 +83,13 @@ func validateSupportedVersion(gv schema.GroupVersion, allowDeprecated, allowExpe
 		"kubeadm.k8s.io/v1beta2":  "v1.22",
 	}
 
-	// Experimental API versions are present here until released.
+	// Experimental API versions are present here until released. Can be used only if allowed.
 	experimentalAPIVersions := map[string]string{}
 
-	// Deprecated API versions are supported by us, but can only be used for migration.
-	deprecatedAPIVersions := map[string]struct{}{}
+	// Deprecated API versions are supported until removed. They throw a warning.
+	deprecatedAPIVersions := map[string]struct{}{
+		"kubeadm.k8s.io/v1beta3": {},
+	}
 
 	gvString := gv.String()