Make pvc storage class annotation immutable after create

pkg/api/validation/BUILD

@@ -30,6 +30,7 @@ go_library(
         "//pkg/api/util:go_default_library",
         "//pkg/api/v1:go_default_library",
         "//pkg/apimachinery/registered:go_default_library",
+        "//pkg/apis/storage/util:go_default_library",
         "//pkg/capabilities:go_default_library",
         "//pkg/labels:go_default_library",
         "//pkg/runtime:go_default_library",
@@ -75,6 +76,7 @@ go_test(
         "//pkg/api/unversioned:go_default_library",
         "//pkg/apimachinery/registered:go_default_library",
         "//pkg/apis/extensions:go_default_library",
+        "//pkg/apis/storage/util:go_default_library",
         "//pkg/capabilities:go_default_library",
         "//pkg/runtime:go_default_library",
         "//pkg/security/apparmor:go_default_library",

pkg/api/validation/validation.go

@@ -34,6 +34,7 @@ import (
 	apiservice "k8s.io/kubernetes/pkg/api/service"
 	unversionedvalidation "k8s.io/kubernetes/pkg/api/unversioned/validation"
 	"k8s.io/kubernetes/pkg/api/v1"
+	storageutil "k8s.io/kubernetes/pkg/apis/storage/util"
 	"k8s.io/kubernetes/pkg/capabilities"
 	"k8s.io/kubernetes/pkg/labels"
 	"k8s.io/kubernetes/pkg/runtime/schema"
@@ -351,6 +352,15 @@ func ValidateImmutableField(newVal, oldVal interface{}, fldPath *field.Path) fie
 	return allErrs
 }
 
+func ValidateImmutableAnnotation(newVal string, oldVal string, annotation string, fldPath *field.Path) field.ErrorList {
+	allErrs := field.ErrorList{}
+
+	if oldVal != newVal {
+		allErrs = append(allErrs, field.Invalid(fldPath.Child("annotations", annotation), newVal, fieldImmutableErrorMsg))
+	}
+	return allErrs
+}
+
 // ValidateObjectMeta validates an object's metadata on creation. It expects that name generation has already
 // been performed.
 // It doesn't return an error for rootscoped resources with namespace, because namespace should already be cleared before.
@@ -1262,11 +1272,15 @@ func ValidatePersistentVolumeClaimUpdate(newPvc, oldPvc *api.PersistentVolumeCla
 		oldPvc.Spec.VolumeName = newPvc.Spec.VolumeName
 		defer func() { oldPvc.Spec.VolumeName = "" }()
 	}
-	// changes to Spec are not allowed, but updates to label/annotations are OK.
+	// changes to Spec are not allowed, but updates to label/and some annotations are OK.
 	// no-op updates pass validation.
 	if !api.Semantic.DeepEqual(newPvc.Spec, oldPvc.Spec) {
 		allErrs = append(allErrs, field.Forbidden(field.NewPath("spec"), "field is immutable after creation"))
 	}
+
+	// storageclass annotation should be immutable after creation
+	allErrs = append(allErrs, ValidateImmutableAnnotation(newPvc.ObjectMeta.Annotations[storageutil.StorageClassAnnotation], oldPvc.ObjectMeta.Annotations[storageutil.StorageClassAnnotation], storageutil.StorageClassAnnotation, field.NewPath("metadata"))...)
+
 	newPvc.Status = oldPvc.Status
 	return allErrs
 }

pkg/api/validation/validation_test.go

@@ -28,6 +28,7 @@ import (
 	"k8s.io/kubernetes/pkg/api/service"
 	"k8s.io/kubernetes/pkg/api/unversioned"
 	"k8s.io/kubernetes/pkg/apimachinery/registered"
+	storageutil "k8s.io/kubernetes/pkg/apis/storage/util"
 	"k8s.io/kubernetes/pkg/capabilities"
 	"k8s.io/kubernetes/pkg/security/apparmor"
 	"k8s.io/kubernetes/pkg/util/intstr"
@@ -661,6 +662,36 @@ func testVolumeClaim(name string, namespace string, spec api.PersistentVolumeCla
 	}
 }
 
+func testVolumeClaimStorageClass(name string, namespace string, annval string, spec api.PersistentVolumeClaimSpec) *api.PersistentVolumeClaim {
+	annotations := map[string]string{
+		storageutil.StorageClassAnnotation: annval,
+	}
+
+	return &api.PersistentVolumeClaim{
+		ObjectMeta: api.ObjectMeta{
+			Name:        name,
+			Namespace:   namespace,
+			Annotations: annotations,
+		},
+		Spec: spec,
+	}
+}
+
+func testVolumeClaimAnnotation(name string, namespace string, ann string, annval string, spec api.PersistentVolumeClaimSpec) *api.PersistentVolumeClaim {
+	annotations := map[string]string{
+		ann: annval,
+	}
+
+	return &api.PersistentVolumeClaim{
+		ObjectMeta: api.ObjectMeta{
+			Name:        name,
+			Namespace:   namespace,
+			Annotations: annotations,
+		},
+		Spec: spec,
+	}
+}
+
 func TestValidatePersistentVolumeClaim(t *testing.T) {
 	scenarios := map[string]struct {
 		isExpectedFailure bool
@@ -814,6 +845,26 @@ func TestValidatePersistentVolumeClaimUpdate(t *testing.T) {
 			},
 		},
 	})
+	validClaimStorageClass := testVolumeClaimStorageClass("foo", "ns", "fast", api.PersistentVolumeClaimSpec{
+		AccessModes: []api.PersistentVolumeAccessMode{
+			api.ReadOnlyMany,
+		},
+		Resources: api.ResourceRequirements{
+			Requests: api.ResourceList{
+				api.ResourceName(api.ResourceStorage): resource.MustParse("10G"),
+			},
+		},
+	})
+	validClaimAnnotation := testVolumeClaimAnnotation("foo", "ns", "description", "foo-description", api.PersistentVolumeClaimSpec{
+		AccessModes: []api.PersistentVolumeAccessMode{
+			api.ReadOnlyMany,
+		},
+		Resources: api.ResourceRequirements{
+			Requests: api.ResourceList{
+				api.ResourceName(api.ResourceStorage): resource.MustParse("10G"),
+			},
+		},
+	})
 	validUpdateClaim := testVolumeClaim("foo", "ns", api.PersistentVolumeClaimSpec{
 		AccessModes: []api.PersistentVolumeAccessMode{
 			api.ReadWriteOnce,
@@ -849,6 +900,40 @@ func TestValidatePersistentVolumeClaimUpdate(t *testing.T) {
 		},
 		VolumeName: "volume",
 	})
+	invalidUpdateClaimStorageClass := testVolumeClaimStorageClass("foo", "ns", "fast2", api.PersistentVolumeClaimSpec{
+		AccessModes: []api.PersistentVolumeAccessMode{
+			api.ReadOnlyMany,
+		},
+		Resources: api.ResourceRequirements{
+			Requests: api.ResourceList{
+				api.ResourceName(api.ResourceStorage): resource.MustParse("10G"),
+			},
+		},
+		VolumeName: "volume",
+	})
+	validUpdateClaimMutableAnnotation := testVolumeClaimAnnotation("foo", "ns", "description", "updated-or-added-foo-description", api.PersistentVolumeClaimSpec{
+		AccessModes: []api.PersistentVolumeAccessMode{
+			api.ReadOnlyMany,
+		},
+		Resources: api.ResourceRequirements{
+			Requests: api.ResourceList{
+				api.ResourceName(api.ResourceStorage): resource.MustParse("10G"),
+			},
+		},
+		VolumeName: "volume",
+	})
+	validAddClaimAnnotation := testVolumeClaimAnnotation("foo", "ns", "description", "updated-or-added-foo-description", api.PersistentVolumeClaimSpec{
+		AccessModes: []api.PersistentVolumeAccessMode{
+			api.ReadWriteOnce,
+			api.ReadOnlyMany,
+		},
+		Resources: api.ResourceRequirements{
+			Requests: api.ResourceList{
+				api.ResourceName(api.ResourceStorage): resource.MustParse("10G"),
+			},
+		},
+		VolumeName: "volume",
+	})
 	scenarios := map[string]struct {
 		isExpectedFailure bool
 		oldClaim          *api.PersistentVolumeClaim
@@ -874,6 +959,21 @@ func TestValidatePersistentVolumeClaimUpdate(t *testing.T) {
 			oldClaim:          validUpdateClaim,
 			newClaim:          invalidUpdateClaimAccessModes,
 		},
+		"invalid-update-change-storage-class-annotation-after-creation": {
+			isExpectedFailure: true,
+			oldClaim:          validClaimStorageClass,
+			newClaim:          invalidUpdateClaimStorageClass,
+		},
+		"valid-update-mutable-annotation": {
+			isExpectedFailure: false,
+			oldClaim:          validClaimAnnotation,
+			newClaim:          validUpdateClaimMutableAnnotation,
+		},
+		"valid-update-add-annotation": {
+			isExpectedFailure: false,
+			oldClaim:          validClaim,
+			newClaim:          validAddClaimAnnotation,
+		},
 	}
 
 	for name, scenario := range scenarios {