StatefulSet PersistentVolumeClaimDeletePolicy

pkg/apis/apps/fuzzer/fuzzer.go

@@ -40,6 +40,17 @@ var Funcs = func(codecs runtimeserializer.CodecFactory) []interface{} {
 			if len(s.Spec.UpdateStrategy.Type) == 0 {
 				s.Spec.UpdateStrategy.Type = apps.RollingUpdateStatefulSetStrategyType
 			}
+			if s.Spec.PersistentVolumeClaimRetentionPolicy == nil {
+				policies := []apps.PersistentVolumeClaimRetentionPolicyType{
+					apps.RetainPersistentVolumeClaimRetentionPolicyType,
+					apps.DeletePersistentVolumeClaimRetentionPolicyType,
+				}
+				choice := int32(c.Rand.Int31())
+				s.Spec.PersistentVolumeClaimRetentionPolicy = &apps.StatefulSetPersistentVolumeClaimRetentionPolicy{
+					WhenDeleted: policies[choice&1],
+					WhenScaled:  policies[(choice>>1)&1],
+				}
+			}
 			if s.Spec.RevisionHistoryLimit == nil {
 				s.Spec.RevisionHistoryLimit = new(int32)
 				*s.Spec.RevisionHistoryLimit = 10

pkg/apis/apps/types.go

@@ -97,6 +97,40 @@ type RollingUpdateStatefulSetStrategy struct {
 	Partition int32
 }
 
+// PersistentVolumeClaimRetentionPolicyType is a string enumeration of the policies that will determine
+// when volumes from the VolumeClaimTemplates will be deleted when the controlling StatefulSet is
+// deleted or scaled down.
+type PersistentVolumeClaimRetentionPolicyType string
+
+const (
+	// RetainPersistentVolumeClaimRetentionPolicyType is the default
+	// PersistentVolumeClaimRetentionPolicy and specifies that
+	// PersistentVolumeClaims associated with StatefulSet VolumeClaimTemplates
+	// will not be deleted.
+	RetainPersistentVolumeClaimRetentionPolicyType PersistentVolumeClaimRetentionPolicyType = "Retain"
+	// DeletePersistentVolumeClaimRetentionPolicyType specifies that
+	// PersistentVolumeClaims associated with StatefulSet VolumeClaimTemplates
+	// will be deleted in the scenario specified in
+	// StatefulSetPersistentVolumeClaimPolicy.
+	DeletePersistentVolumeClaimRetentionPolicyType PersistentVolumeClaimRetentionPolicyType = "Delete"
+)
+
+// StatefulSetPersistentVolumeClaimRetentionPolicy describes the policy used for PVCs
+// created from the StatefulSet VolumeClaimTemplates.
+type StatefulSetPersistentVolumeClaimRetentionPolicy struct {
+	// WhenDeleted specifies what happens to PVCs created from StatefulSet
+	// VolumeClaimTemplates when the StatefulSet is deleted. The default policy
+	// of `Retain` causes PVCs to not be affected by StatefulSet deletion. The
+	// `Delete` policy causes those PVCs to be deleted.
+	WhenDeleted PersistentVolumeClaimRetentionPolicyType
+	// WhenScaled specifies what happens to PVCs created from StatefulSet
+	// VolumeClaimTemplates when the StatefulSet is scaled down. The default
+	// policy of `Retain` causes PVCs to not be affected by a scaledown. The
+	// `Delete` policy causes the associated PVCs for any excess pods above
+	// the replica count to be deleted.
+	WhenScaled PersistentVolumeClaimRetentionPolicyType
+}
+
 // A StatefulSetSpec is the specification of a StatefulSet.
 type StatefulSetSpec struct {
 	// Replicas is the desired number of replicas of the given Template.
@@ -164,6 +198,12 @@ type StatefulSetSpec struct {
 	// This is an alpha field and requires enabling StatefulSetMinReadySeconds feature gate.
 	// +optional
 	MinReadySeconds int32
+
+	// PersistentVolumeClaimRetentionPolicy describes the policy used for PVCs created from
+	// the StatefulSet VolumeClaimTemplates. This requires the
+	// StatefulSetAutoDeletePVC feature gate to be enabled, which is alpha.
+	// +optional
+	PersistentVolumeClaimRetentionPolicy *StatefulSetPersistentVolumeClaimRetentionPolicy
 }
 
 // StatefulSetStatus represents the current state of a StatefulSet.

pkg/apis/apps/v1/defaults.go

@@ -20,6 +20,8 @@ import (
 	appsv1 "k8s.io/api/apps/v1"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/util/intstr"
+	utilfeature "k8s.io/apiserver/pkg/util/feature"
+	"k8s.io/kubernetes/pkg/features"
 )
 
 func addDefaultingFuncs(scheme *runtime.Scheme) error {
@@ -117,6 +119,18 @@ func SetDefaults_StatefulSet(obj *appsv1.StatefulSet) {
 		*obj.Spec.UpdateStrategy.RollingUpdate.Partition = 0
 	}
 
+	if utilfeature.DefaultFeatureGate.Enabled(features.StatefulSetAutoDeletePVC) {
+		if obj.Spec.PersistentVolumeClaimRetentionPolicy == nil {
+			obj.Spec.PersistentVolumeClaimRetentionPolicy = &appsv1.StatefulSetPersistentVolumeClaimRetentionPolicy{}
+		}
+		if len(obj.Spec.PersistentVolumeClaimRetentionPolicy.WhenDeleted) == 0 {
+			obj.Spec.PersistentVolumeClaimRetentionPolicy.WhenDeleted = appsv1.RetainPersistentVolumeClaimRetentionPolicyType
+		}
+		if len(obj.Spec.PersistentVolumeClaimRetentionPolicy.WhenScaled) == 0 {
+			obj.Spec.PersistentVolumeClaimRetentionPolicy.WhenScaled = appsv1.RetainPersistentVolumeClaimRetentionPolicyType
+		}
+	}
+
 	if obj.Spec.Replicas == nil {
 		obj.Spec.Replicas = new(int32)
 		*obj.Spec.Replicas = 1

pkg/apis/apps/v1/defaults_test.go

@@ -27,10 +27,13 @@ import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/runtime"
 	"k8s.io/apimachinery/pkg/util/intstr"
+	utilfeature "k8s.io/apiserver/pkg/util/feature"
+	featuregatetesting "k8s.io/component-base/featuregate/testing"
 	"k8s.io/kubernetes/pkg/api/legacyscheme"
 	_ "k8s.io/kubernetes/pkg/apis/apps/install"
 	. "k8s.io/kubernetes/pkg/apis/apps/v1"
 	_ "k8s.io/kubernetes/pkg/apis/core/install"
+	"k8s.io/kubernetes/pkg/features"
 	utilpointer "k8s.io/utils/pointer"
 )
 
@@ -193,10 +196,13 @@ func TestSetDefaultStatefulSet(t *testing.T) {
 	}
 
 	tests := []struct {
-		original *appsv1.StatefulSet
-		expected *appsv1.StatefulSet
+		name                    string
+		original                *appsv1.StatefulSet
+		expected                *appsv1.StatefulSet
+		enablePVCDeletionPolicy bool
 	}{
-		{ // labels and default update strategy
+		{
+			name: "labels and default update strategy",
 			original: &appsv1.StatefulSet{
 				Spec: appsv1.StatefulSetSpec{
 					Template: defaultTemplate,
@@ -221,7 +227,8 @@ func TestSetDefaultStatefulSet(t *testing.T) {
 				},
 			},
 		},
-		{ // Alternate update strategy
+		{
+			name: "Alternate update strategy",
 			original: &appsv1.StatefulSet{
 				Spec: appsv1.StatefulSetSpec{
 					Template: defaultTemplate,
@@ -246,7 +253,8 @@ func TestSetDefaultStatefulSet(t *testing.T) {
 				},
 			},
 		},
-		{ // Parallel pod management policy.
+		{
+			name: "Parallel pod management policy",
 			original: &appsv1.StatefulSet{
 				Spec: appsv1.StatefulSetSpec{
 					Template:            defaultTemplate,
@@ -272,7 +280,8 @@ func TestSetDefaultStatefulSet(t *testing.T) {
 				},
 			},
 		},
-		{ // UpdateStrategy.RollingUpdate.Partition is not lost when UpdateStrategy.Type is not set
+		{
+			name: "UpdateStrategy.RollingUpdate.Partition is not lost when UpdateStrategy.Type is not set",
 			original: &appsv1.StatefulSet{
 				Spec: appsv1.StatefulSetSpec{
 					Template: defaultTemplate,
@@ -302,20 +311,151 @@ func TestSetDefaultStatefulSet(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "PVC delete policy enabled, no policy specified",
+			original: &appsv1.StatefulSet{
+				Spec: appsv1.StatefulSetSpec{
+					Template: defaultTemplate,
+				},
+			},
+			expected: &appsv1.StatefulSet{
+				ObjectMeta: metav1.ObjectMeta{
+					Labels: defaultLabels,
+				},
+				Spec: appsv1.StatefulSetSpec{
+					Replicas:            &defaultReplicas,
+					Template:            defaultTemplate,
+					PodManagementPolicy: appsv1.OrderedReadyPodManagement,
+					UpdateStrategy: appsv1.StatefulSetUpdateStrategy{
+						Type: appsv1.RollingUpdateStatefulSetStrategyType,
+						RollingUpdate: &appsv1.RollingUpdateStatefulSetStrategy{
+							Partition: &defaultPartition,
+						},
+					},
+					PersistentVolumeClaimRetentionPolicy: &appsv1.StatefulSetPersistentVolumeClaimRetentionPolicy{
+						WhenDeleted: appsv1.RetainPersistentVolumeClaimRetentionPolicyType,
+						WhenScaled:  appsv1.RetainPersistentVolumeClaimRetentionPolicyType,
+					},
+					RevisionHistoryLimit: utilpointer.Int32Ptr(10),
+				},
+			},
+			enablePVCDeletionPolicy: true,
+		},
+		{
+			name: "PVC delete policy enabled, with scaledown policy specified",
+			original: &appsv1.StatefulSet{
+				Spec: appsv1.StatefulSetSpec{
+					Template: defaultTemplate,
+					PersistentVolumeClaimRetentionPolicy: &appsv1.StatefulSetPersistentVolumeClaimRetentionPolicy{
+						WhenScaled: appsv1.DeletePersistentVolumeClaimRetentionPolicyType,
+					},
+				},
+			},
+			expected: &appsv1.StatefulSet{
+				ObjectMeta: metav1.ObjectMeta{
+					Labels: defaultLabels,
+				},
+				Spec: appsv1.StatefulSetSpec{
+					Replicas:            &defaultReplicas,
+					Template:            defaultTemplate,
+					PodManagementPolicy: appsv1.OrderedReadyPodManagement,
+					UpdateStrategy: appsv1.StatefulSetUpdateStrategy{
+						Type: appsv1.RollingUpdateStatefulSetStrategyType,
+						RollingUpdate: &appsv1.RollingUpdateStatefulSetStrategy{
+							Partition: &defaultPartition,
+						},
+					},
+					PersistentVolumeClaimRetentionPolicy: &appsv1.StatefulSetPersistentVolumeClaimRetentionPolicy{
+						WhenDeleted: appsv1.RetainPersistentVolumeClaimRetentionPolicyType,
+						WhenScaled:  appsv1.DeletePersistentVolumeClaimRetentionPolicyType,
+					},
+					RevisionHistoryLimit: utilpointer.Int32Ptr(10),
+				},
+			},
+			enablePVCDeletionPolicy: true,
+		},
+		{
+			name: "PVC delete policy disabled, with set deletion policy specified",
+			original: &appsv1.StatefulSet{
+				Spec: appsv1.StatefulSetSpec{
+					Template: defaultTemplate,
+					PersistentVolumeClaimRetentionPolicy: &appsv1.StatefulSetPersistentVolumeClaimRetentionPolicy{
+						WhenDeleted: appsv1.DeletePersistentVolumeClaimRetentionPolicyType,
+					},
+				},
+			},
+			expected: &appsv1.StatefulSet{
+				ObjectMeta: metav1.ObjectMeta{
+					Labels: defaultLabels,
+				},
+				Spec: appsv1.StatefulSetSpec{
+					Replicas:            &defaultReplicas,
+					Template:            defaultTemplate,
+					PodManagementPolicy: appsv1.OrderedReadyPodManagement,
+					UpdateStrategy: appsv1.StatefulSetUpdateStrategy{
+						Type: appsv1.RollingUpdateStatefulSetStrategyType,
+						RollingUpdate: &appsv1.RollingUpdateStatefulSetStrategy{
+							Partition: &defaultPartition,
+						},
+					},
+					PersistentVolumeClaimRetentionPolicy: &appsv1.StatefulSetPersistentVolumeClaimRetentionPolicy{
+						WhenDeleted: appsv1.DeletePersistentVolumeClaimRetentionPolicyType,
+						WhenScaled:  appsv1.RetainPersistentVolumeClaimRetentionPolicyType,
+					},
+					RevisionHistoryLimit: utilpointer.Int32Ptr(10),
+				},
+			},
+			enablePVCDeletionPolicy: true,
+		},
+		{
+			name: "PVC delete policy disabled, with policy specified",
+			original: &appsv1.StatefulSet{
+				Spec: appsv1.StatefulSetSpec{
+					Template: defaultTemplate,
+					PersistentVolumeClaimRetentionPolicy: &appsv1.StatefulSetPersistentVolumeClaimRetentionPolicy{
+						WhenScaled: appsv1.DeletePersistentVolumeClaimRetentionPolicyType,
+					},
+				},
+			},
+			expected: &appsv1.StatefulSet{
+				ObjectMeta: metav1.ObjectMeta{
+					Labels: defaultLabels,
+				},
+				Spec: appsv1.StatefulSetSpec{
+					Replicas:            &defaultReplicas,
+					Template:            defaultTemplate,
+					PodManagementPolicy: appsv1.OrderedReadyPodManagement,
+					UpdateStrategy: appsv1.StatefulSetUpdateStrategy{
+						Type: appsv1.RollingUpdateStatefulSetStrategyType,
+						RollingUpdate: &appsv1.RollingUpdateStatefulSetStrategy{
+							Partition: &defaultPartition,
+						},
+					},
+					PersistentVolumeClaimRetentionPolicy: &appsv1.StatefulSetPersistentVolumeClaimRetentionPolicy{
+						WhenScaled: appsv1.DeletePersistentVolumeClaimRetentionPolicyType,
+					},
+					RevisionHistoryLimit: utilpointer.Int32Ptr(10),
+				},
+			},
+			enablePVCDeletionPolicy: false,
+		},
 	}
 
-	for i, test := range tests {
-		original := test.original
-		expected := test.expected
-		obj2 := roundTrip(t, runtime.Object(original))
-		got, ok := obj2.(*appsv1.StatefulSet)
-		if !ok {
-			t.Errorf("(%d) unexpected object: %v", i, got)
-			t.FailNow()
-		}
-		if !apiequality.Semantic.DeepEqual(got.Spec, expected.Spec) {
-			t.Errorf("(%d) got different than expected\ngot:\n\t%+v\nexpected:\n\t%+v", i, got.Spec, expected.Spec)
-		}
+	for _, test := range tests {
+		test := test
+		t.Run(test.name, func(t *testing.T) {
+			defer featuregatetesting.SetFeatureGateDuringTest(t, utilfeature.DefaultFeatureGate, features.StatefulSetAutoDeletePVC, test.enablePVCDeletionPolicy)()
+
+			obj2 := roundTrip(t, runtime.Object(test.original))
+			got, ok := obj2.(*appsv1.StatefulSet)
+			if !ok {
+				t.Errorf("unexpected object: %v", got)
+				t.FailNow()
+			}
+			if !apiequality.Semantic.DeepEqual(got.Spec, test.expected.Spec) {
+				t.Errorf("got different than expected\ngot:\n\t%+v\nexpected:\n\t%+v", got.Spec, test.expected.Spec)
+			}
+		})
 	}
 }