ignore clusterName on create and update

pkg/api/rest/create.go

@@ -71,6 +71,9 @@ func BeforeCreate(strategy RESTCreateStrategy, ctx api.Context, obj runtime.Obje
 	api.FillObjectMetaSystemFields(ctx, objectMeta)
 	api.GenerateName(strategy, objectMeta)
 
+	// ClusterName is ignored and should not be saved
+	objectMeta.ClusterName = ""
+
 	if errs := strategy.Validate(ctx, obj); len(errs) > 0 {
 		return errors.NewInvalid(kind.GroupKind(), objectMeta.Name, errs)
 	}