kubeadm: Deprecate hyperkube use

As the hyperkube image is itself deprecated and moved out of tree, its use with
kubeadm gets deprecated too. Hence, deprecation messages will be printed when
it is used.

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

cmd/kubeadm/app/images/BUILD

@@ -14,6 +14,7 @@ go_library(
         "//cmd/kubeadm/app/apis/kubeadm:go_default_library",
         "//cmd/kubeadm/app/constants:go_default_library",
         "//cmd/kubeadm/app/util:go_default_library",
+        "//vendor/k8s.io/klog:go_default_library",
     ],
 )
 

cmd/kubeadm/app/images/images.go

@@ -19,6 +19,7 @@ package images
 import (
 	"fmt"
 
+	"k8s.io/klog"
 	kubeadmapi "k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm"
 	"k8s.io/kubernetes/cmd/kubeadm/app/constants"
 	kubeadmutil "k8s.io/kubernetes/cmd/kubeadm/app/util"
@@ -32,7 +33,8 @@ func GetGenericImage(prefix, image, tag string) string {
 // GetKubernetesImage generates and returns the image for the components managed in the Kubernetes main repository,
 // including the control-plane components and kube-proxy. If specified, the HyperKube image will be used.
 func GetKubernetesImage(image string, cfg *kubeadmapi.ClusterConfiguration) string {
-	if cfg.UseHyperKubeImage {
+	if cfg.UseHyperKubeImage && image != constants.HyperKube {
+		klog.Warningf(`WARNING: DEPRECATED use of the "hyperkube" image in place of %q`, image)
 		image = constants.HyperKube
 	}
 	repoPrefix := cfg.GetControlPlaneImageRepository()
@@ -91,6 +93,7 @@ func GetControlPlaneImages(cfg *kubeadmapi.ClusterConfiguration) []string {
 
 	// start with core kubernetes images
 	if cfg.UseHyperKubeImage {
+		klog.Warningln(`WARNING: DEPRECATED use of the "hyperkube" image for the Kubernetes control plane`)
 		imgs = append(imgs, GetKubernetesImage(constants.HyperKube, cfg))
 	} else {
 		imgs = append(imgs, GetKubernetesImage(constants.KubeAPIServer, cfg))