Remove PersistentVolumeLabel admission plugin

Remove useless admission plugin.

* It has been deprecated for years.
* All in-tree cloud providers were removed, so the admission plugin does not have
  any way to get PV labels.
* There is a replacement in https://github.com/kubernetes-sigs/cloud-pv-admission-labeler

Author: jsafrane

hack/make-rules/test-cmd.sh

@@ -56,7 +56,7 @@ function run_kube_apiserver() {
 
   # Admission Controllers to invoke prior to persisting objects in cluster
   ENABLE_ADMISSION_PLUGINS="LimitRanger,ResourceQuota"
-  DISABLE_ADMISSION_PLUGINS="ServiceAccount,PersistentVolumeLabel,DefaultStorageClass,DefaultTolerationSeconds,MutatingAdmissionWebhook,ValidatingAdmissionWebhook,StorageObjectInUseProtection"
+  DISABLE_ADMISSION_PLUGINS="ServiceAccount,DefaultStorageClass,DefaultTolerationSeconds,MutatingAdmissionWebhook,ValidatingAdmissionWebhook,StorageObjectInUseProtection"
 
   # Include RBAC (to exercise bootstrapping), and AlwaysAllow to allow all actions
   AUTHORIZATION_MODE="RBAC,AlwaysAllow"

pkg/kubeapiserver/options/plugins.go

@@ -49,7 +49,6 @@ import (
 	"k8s.io/kubernetes/plugin/pkg/admission/runtimeclass"
 	"k8s.io/kubernetes/plugin/pkg/admission/security/podsecurity"
 	"k8s.io/kubernetes/plugin/pkg/admission/serviceaccount"
-	"k8s.io/kubernetes/plugin/pkg/admission/storage/persistentvolume/label"
 	"k8s.io/kubernetes/plugin/pkg/admission/storage/persistentvolume/resize"
 	"k8s.io/kubernetes/plugin/pkg/admission/storage/storageclass/setdefault"
 	"k8s.io/kubernetes/plugin/pkg/admission/storage/storageobjectinuseprotection"
@@ -82,7 +81,6 @@ var AllOrderedPlugins = []string{
 	podtolerationrestriction.PluginName,     // PodTolerationRestriction
 	eventratelimit.PluginName,               // EventRateLimit
 	extendedresourcetoleration.PluginName,   // ExtendedResourceToleration
-	label.PluginName,                        // PersistentVolumeLabel
 	setdefault.PluginName,                   // DefaultStorageClass
 	storageobjectinuseprotection.PluginName, // StorageObjectInUseProtection
 	gc.PluginName,                           // OwnerReferencesPermissionEnforcement
@@ -126,7 +124,6 @@ func RegisterAllAdmissionPlugins(plugins *admission.Plugins) {
 	exists.Register(plugins)
 	noderestriction.Register(plugins)
 	nodetaint.Register(plugins)
-	label.Register(plugins) // DEPRECATED, future PVs should not rely on labels for zone topology
 	podnodeselector.Register(plugins)
 	podtolerationrestriction.Register(plugins)
 	runtimeclass.Register(plugins)