Added PVC Protection Controller

This controller removes protection finalizer from PVCs that are being
deleted and are not referenced by any pod.

cmd/kube-controller-manager/app/BUILD

@@ -79,6 +79,7 @@ go_library(
         "//pkg/controller/volume/attachdetach:go_default_library",
         "//pkg/controller/volume/expand:go_default_library",
         "//pkg/controller/volume/persistentvolume:go_default_library",
+        "//pkg/controller/volume/pvcprotection:go_default_library",
         "//pkg/features:go_default_library",
         "//pkg/quota/generic:go_default_library",
         "//pkg/quota/install:go_default_library",

cmd/kube-controller-manager/app/controllermanager.go

@@ -359,6 +359,7 @@ func NewControllerInitializers() map[string]InitFunc {
 	controllers["attachdetach"] = startAttachDetachController
 	controllers["persistentvolume-expander"] = startVolumeExpandController
 	controllers["clusterrole-aggregation"] = startClusterRoleAggregrationController
+	controllers["pvc-protection"] = startPVCProtectionController
 
 	return controllers
 }

cmd/kube-controller-manager/app/core.go

@@ -53,6 +53,7 @@ import (
 	"k8s.io/kubernetes/pkg/controller/volume/attachdetach"
 	"k8s.io/kubernetes/pkg/controller/volume/expand"
 	persistentvolumecontroller "k8s.io/kubernetes/pkg/controller/volume/persistentvolume"
+	"k8s.io/kubernetes/pkg/controller/volume/pvcprotection"
 	"k8s.io/kubernetes/pkg/features"
 	"k8s.io/kubernetes/pkg/quota/generic"
 	quotainstall "k8s.io/kubernetes/pkg/quota/install"
@@ -376,3 +377,15 @@ func startGarbageCollectorController(ctx ControllerContext) (bool, error) {
 
 	return true, nil
 }
+
+func startPVCProtectionController(ctx ControllerContext) (bool, error) {
+	if utilfeature.DefaultFeatureGate.Enabled(features.PVCProtection) {
+		go pvcprotection.NewPVCProtectionController(
+			ctx.InformerFactory.Core().V1().PersistentVolumeClaims(),
+			ctx.InformerFactory.Core().V1().Pods(),
+			ctx.ClientBuilder.ClientOrDie("pvc-protection-controller"),
+		).Run(1, ctx.Stop)
+		return true, nil
+	}
+	return false, nil
+}

pkg/controller/BUILD

@@ -133,6 +133,7 @@ filegroup(
         "//pkg/controller/volume/events:all-srcs",
         "//pkg/controller/volume/expand:all-srcs",
         "//pkg/controller/volume/persistentvolume:all-srcs",
+        "//pkg/controller/volume/pvcprotection:all-srcs",
     ],
     tags = ["automanaged"],
 )

pkg/controller/volume/pvcprotection/BUILD

@@ -0,0 +1,61 @@
+load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
+
+go_library(
+    name = "go_default_library",
+    srcs = ["pvc_protection_controller.go"],
+    importpath = "k8s.io/kubernetes/pkg/controller/volume/pvcprotection",
+    visibility = ["//visibility:public"],
+    deps = [
+        "//pkg/controller:go_default_library",
+        "//pkg/util/metrics:go_default_library",
+        "//pkg/volume/util:go_default_library",
+        "//pkg/volume/util/volumehelper:go_default_library",
+        "//vendor/github.com/golang/glog:go_default_library",
+        "//vendor/k8s.io/api/core/v1:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/api/errors:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/labels:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/util/runtime:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/util/wait:go_default_library",
+        "//vendor/k8s.io/client-go/informers/core/v1:go_default_library",
+        "//vendor/k8s.io/client-go/kubernetes:go_default_library",
+        "//vendor/k8s.io/client-go/listers/core/v1:go_default_library",
+        "//vendor/k8s.io/client-go/tools/cache:go_default_library",
+        "//vendor/k8s.io/client-go/util/workqueue:go_default_library",
+    ],
+)
+
+go_test(
+    name = "go_default_test",
+    srcs = ["pvc_protection_controller_test.go"],
+    importpath = "k8s.io/kubernetes/pkg/controller/volume/pvcprotection",
+    library = ":go_default_library",
+    deps = [
+        "//pkg/controller:go_default_library",
+        "//pkg/volume/util:go_default_library",
+        "//vendor/github.com/davecgh/go-spew/spew:go_default_library",
+        "//vendor/github.com/golang/glog:go_default_library",
+        "//vendor/k8s.io/api/core/v1:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/api/errors:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/api/meta:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/runtime:go_default_library",
+        "//vendor/k8s.io/apimachinery/pkg/runtime/schema:go_default_library",
+        "//vendor/k8s.io/client-go/informers:go_default_library",
+        "//vendor/k8s.io/client-go/kubernetes/fake:go_default_library",
+        "//vendor/k8s.io/client-go/testing:go_default_library",
+    ],
+)
+
+filegroup(
+    name = "package-srcs",
+    srcs = glob(["**"]),
+    tags = ["automanaged"],
+    visibility = ["//visibility:private"],
+)
+
+filegroup(
+    name = "all-srcs",
+    srcs = [":package-srcs"],
+    tags = ["automanaged"],
+    visibility = ["//visibility:public"],
+)

pkg/controller/volume/pvcprotection/pvc_protection_controller.go

@@ -0,0 +1,284 @@
+/*
+Copyright 2017 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package pvcprotection
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/golang/glog"
+	"k8s.io/api/core/v1"
+	apierrs "k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/apimachinery/pkg/labels"
+	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
+	"k8s.io/apimachinery/pkg/util/wait"
+	coreinformers "k8s.io/client-go/informers/core/v1"
+	clientset "k8s.io/client-go/kubernetes"
+	corelisters "k8s.io/client-go/listers/core/v1"
+	"k8s.io/client-go/tools/cache"
+	"k8s.io/client-go/util/workqueue"
+	"k8s.io/kubernetes/pkg/controller"
+	"k8s.io/kubernetes/pkg/util/metrics"
+	volumeutil "k8s.io/kubernetes/pkg/volume/util"
+	"k8s.io/kubernetes/pkg/volume/util/volumehelper"
+)
+
+// Controller is controller that removes PVCProtectionFinalizer
+// from PVCs that are used by no pods.
+type Controller struct {
+	client clientset.Interface
+
+	pvcLister       corelisters.PersistentVolumeClaimLister
+	pvcListerSynced cache.InformerSynced
+
+	podLister       corelisters.PodLister
+	podListerSynced cache.InformerSynced
+
+	queue workqueue.RateLimitingInterface
+}
+
+// NewPVCProtectionController returns a new *{VCProtectionController.
+func NewPVCProtectionController(pvcInformer coreinformers.PersistentVolumeClaimInformer, podInformer coreinformers.PodInformer, cl clientset.Interface) *Controller {
+	e := &Controller{
+		client: cl,
+		queue:  workqueue.NewNamedRateLimitingQueue(workqueue.DefaultControllerRateLimiter(), "pvcprotection"),
+	}
+	if cl != nil && cl.CoreV1().RESTClient().GetRateLimiter() != nil {
+		metrics.RegisterMetricAndTrackRateLimiterUsage("persistentvolumeclaim_protection_controller", cl.CoreV1().RESTClient().GetRateLimiter())
+	}
+
+	e.pvcLister = pvcInformer.Lister()
+	e.pvcListerSynced = pvcInformer.Informer().HasSynced
+	pvcInformer.Informer().AddEventHandler(cache.ResourceEventHandlerFuncs{
+		AddFunc: e.pvcAddedUpdated,
+		UpdateFunc: func(old, new interface{}) {
+			e.pvcAddedUpdated(new)
+		},
+	})
+
+	e.podLister = podInformer.Lister()
+	e.podListerSynced = podInformer.Informer().HasSynced
+	podInformer.Informer().AddEventHandler(cache.ResourceEventHandlerFuncs{
+		AddFunc: func(obj interface{}) {
+			e.podAddedDeletedUpdated(obj, false)
+		},
+		DeleteFunc: func(obj interface{}) {
+			e.podAddedDeletedUpdated(obj, true)
+		},
+		UpdateFunc: func(old, new interface{}) {
+			e.podAddedDeletedUpdated(new, false)
+		},
+	})
+
+	return e
+}
+
+// Run runs the controller goroutines.
+func (c *Controller) Run(workers int, stopCh <-chan struct{}) {
+	defer utilruntime.HandleCrash()
+	defer c.queue.ShutDown()
+
+	glog.Infof("Starting PVC protection controller")
+	defer glog.Infof("Shutting down PVC protection controller")
+
+	if !controller.WaitForCacheSync("PVC protection", stopCh, c.pvcListerSynced, c.podListerSynced) {
+		return
+	}
+
+	for i := 0; i < workers; i++ {
+		go wait.Until(c.runWorker, time.Second, stopCh)
+	}
+
+	<-stopCh
+}
+
+func (c *Controller) runWorker() {
+	for c.processNextWorkItem() {
+	}
+}
+
+// processNextWorkItem deals with one pvcKey off the queue.  It returns false when it's time to quit.
+func (c *Controller) processNextWorkItem() bool {
+	pvcKey, quit := c.queue.Get()
+	if quit {
+		return false
+	}
+	defer c.queue.Done(pvcKey)
+
+	pvcNamespace, pvcName, err := cache.SplitMetaNamespaceKey(pvcKey.(string))
+	if err != nil {
+		utilruntime.HandleError(fmt.Errorf("Error parsing PVC key %q: %v", pvcKey, err))
+		return true
+	}
+
+	err = c.processPVC(pvcNamespace, pvcName)
+	if err == nil {
+		c.queue.Forget(pvcKey)
+		return true
+	}
+
+	utilruntime.HandleError(fmt.Errorf("PVC %v failed with : %v", pvcKey, err))
+	c.queue.AddRateLimited(pvcKey)
+
+	return true
+}
+
+func (c *Controller) processPVC(pvcNamespace, pvcName string) error {
+	glog.V(4).Infof("Processing PVC %s/%s", pvcNamespace, pvcName)
+	startTime := time.Now()
+	defer func() {
+		glog.V(4).Infof("Finished processing PVC %s/%s (%v)", pvcNamespace, pvcName, time.Now().Sub(startTime))
+	}()
+
+	pvc, err := c.pvcLister.PersistentVolumeClaims(pvcNamespace).Get(pvcName)
+	if apierrs.IsNotFound(err) {
+		glog.V(4).Infof("PVC %s/%s not found, ignoring", pvcNamespace, pvcName)
+		return nil
+	}
+	if err != nil {
+		return err
+	}
+
+	if volumeutil.IsPVCBeingDeleted(pvc) && volumeutil.IsProtectionFinalizerPresent(pvc) {
+		// PVC should be deleted. Check if it's used and remove finalizer if
+		// it's not.
+		isUsed, err := c.isBeingUsed(pvc)
+		if err != nil {
+			return err
+		}
+		if !isUsed {
+			return c.removeFinalizer(pvc)
+		}
+	}
+
+	if !volumeutil.IsPVCBeingDeleted(pvc) && !volumeutil.IsProtectionFinalizerPresent(pvc) {
+		// PVC is not being deleted -> it should have the finalizer. The
+		// finalizer should be added by admission plugin, this is just to add
+		// the finalizer to old PVCs that were created before the admission
+		// plugin was enabled.
+		return c.addFinalizer(pvc)
+	}
+	return nil
+}
+
+func (c *Controller) addFinalizer(pvc *v1.PersistentVolumeClaim) error {
+	claimClone := pvc.DeepCopy()
+	volumeutil.AddProtectionFinalizer(claimClone)
+	_, err := c.client.CoreV1().PersistentVolumeClaims(claimClone.Namespace).Update(claimClone)
+	if err != nil {
+		glog.V(3).Infof("Error adding protection finalizer to PVC %s/%s: %v", pvc.Namespace, pvc.Name)
+		return err
+	}
+	glog.V(3).Infof("Added protection finalizer to PVC %s/%s", pvc.Namespace, pvc.Name)
+	return nil
+}
+
+func (c *Controller) removeFinalizer(pvc *v1.PersistentVolumeClaim) error {
+	claimClone := pvc.DeepCopy()
+	volumeutil.RemoveProtectionFinalizer(claimClone)
+	_, err := c.client.CoreV1().PersistentVolumeClaims(claimClone.Namespace).Update(claimClone)
+	if err != nil {
+		glog.V(3).Infof("Error removing protection finalizer from PVC %s/%s: %v", pvc.Namespace, pvc.Name, err)
+		return err
+	}
+	glog.V(3).Infof("Removed protection finalizer from PVC %s/%s", pvc.Namespace, pvc.Name)
+	return nil
+}
+
+func (c *Controller) isBeingUsed(pvc *v1.PersistentVolumeClaim) (bool, error) {
+	pods, err := c.podLister.Pods(pvc.Namespace).List(labels.Everything())
+	if err != nil {
+		return false, err
+	}
+	for _, pod := range pods {
+		if pod.Spec.NodeName == "" {
+			// This pod is not scheduled. We have a predicated in scheduler that
+			// prevents scheduling pods with deletion timestamp, so we can be
+			// pretty sure it won't be scheduled in parallel to this check.
+			// Therefore this pod does not block the PVC from deletion.
+			glog.V(4).Infof("Skipping unscheduled pod %s when checking PVC %s/%s", pod.Name, pvc.Namespace, pvc.Name)
+			continue
+		}
+		if volumehelper.IsPodTerminated(pod, pod.Status) {
+			// This pod is being unmounted/detached or is already
+			// unmounted/detached. It does not block the PVC from deletion.
+			continue
+		}
+		for _, volume := range pod.Spec.Volumes {
+			if volume.PersistentVolumeClaim == nil {
+				continue
+			}
+			if volume.PersistentVolumeClaim.ClaimName == pvc.Name {
+				glog.V(2).Infof("Keeping PVC %s/%s, it is used by pod %s/%s", pvc.Namespace, pvc.Name, pod.Namespace, pod.Name)
+				return true, nil
+			}
+		}
+	}
+
+	glog.V(3).Infof("PVC %s/%s is unused", pvc.Namespace, pvc.Name)
+	return false, nil
+}
+
+// pvcAddedUpdated reacts to pvc added/updated/deleted events
+func (c *Controller) pvcAddedUpdated(obj interface{}) {
+	pvc, ok := obj.(*v1.PersistentVolumeClaim)
+	if !ok {
+		utilruntime.HandleError(fmt.Errorf("PVC informer returned non-PVC object: %#v", obj))
+		return
+	}
+	key, err := cache.DeletionHandlingMetaNamespaceKeyFunc(pvc)
+	if err != nil {
+		utilruntime.HandleError(fmt.Errorf("Couldn't get key for Persistent Volume Claim %#v: %v", pvc, err))
+		return
+	}
+	glog.V(4).Infof("Got event on PVC %s", key)
+
+	if (!volumeutil.IsPVCBeingDeleted(pvc) && !volumeutil.IsProtectionFinalizerPresent(pvc)) || (volumeutil.IsPVCBeingDeleted(pvc) && volumeutil.IsProtectionFinalizerPresent(pvc)) {
+		c.queue.Add(key)
+	}
+}
+
+// podAddedDeletedUpdated reacts to Pod events
+func (c *Controller) podAddedDeletedUpdated(obj interface{}, deleted bool) {
+	pod, ok := obj.(*v1.Pod)
+	if !ok {
+		tombstone, ok := obj.(cache.DeletedFinalStateUnknown)
+		if !ok {
+			utilruntime.HandleError(fmt.Errorf("Couldn't get object from tombstone %#v", obj))
+			return
+		}
+		pod, ok = tombstone.Obj.(*v1.Pod)
+		if !ok {
+			utilruntime.HandleError(fmt.Errorf("Tombstone contained object that is not a Pod %#v", obj))
+			return
+		}
+	}
+
+	// Filter out pods that can't help us to remove a finalizer on PVC
+	if !deleted && !volumehelper.IsPodTerminated(pod, pod.Status) && pod.Spec.NodeName != "" {
+		return
+	}
+
+	glog.V(4).Infof("Got event on pod %s/%s", pod.Namespace, pod.Name)
+
+	// Enqueue all PVCs that the pod uses
+	for _, volume := range pod.Spec.Volumes {
+		if volume.PersistentVolumeClaim != nil {
+			c.queue.Add(pod.Namespace + "/" + volume.PersistentVolumeClaim.ClaimName)
+		}
+	}
+}

pkg/controller/volume/pvcprotection/pvc_protection_controller_test.go

@@ -0,0 +1,397 @@
+/*
+Copyright 2017 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package pvcprotection
+
+import (
+	"errors"
+	"reflect"
+	"testing"
+	"time"
+
+	"github.com/davecgh/go-spew/spew"
+	"github.com/golang/glog"
+
+	"k8s.io/api/core/v1"
+	apierrors "k8s.io/apimachinery/pkg/api/errors"
+	"k8s.io/apimachinery/pkg/api/meta"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"k8s.io/client-go/informers"
+	"k8s.io/client-go/kubernetes/fake"
+	clienttesting "k8s.io/client-go/testing"
+	"k8s.io/kubernetes/pkg/controller"
+	volumeutil "k8s.io/kubernetes/pkg/volume/util"
+)
+
+type reaction struct {
+	verb      string
+	resource  string
+	reactorfn clienttesting.ReactionFunc
+}
+
+const (
+	defaultNS       = "default"
+	defaultPVCName  = "pvc1"
+	defaultPodName  = "pod1"
+	defaultNodeName = "node1"
+)
+
+func pod() *v1.Pod {
+	return &v1.Pod{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      defaultPodName,
+			Namespace: defaultNS,
+		},
+		Spec: v1.PodSpec{
+			NodeName: defaultNodeName,
+		},
+		Status: v1.PodStatus{
+			Phase: v1.PodPending,
+		},
+	}
+}
+
+func unscheduled(pod *v1.Pod) *v1.Pod {
+	pod.Spec.NodeName = ""
+	return pod
+}
+
+func withPVC(pvcName string, pod *v1.Pod) *v1.Pod {
+	volume := v1.Volume{
+		Name: pvcName,
+		VolumeSource: v1.VolumeSource{
+			PersistentVolumeClaim: &v1.PersistentVolumeClaimVolumeSource{
+				ClaimName: pvcName,
+			},
+		},
+	}
+	pod.Spec.Volumes = append(pod.Spec.Volumes, volume)
+	return pod
+}
+
+func withEmptyDir(pod *v1.Pod) *v1.Pod {
+	volume := v1.Volume{
+		Name: "emptyDir",
+		VolumeSource: v1.VolumeSource{
+			EmptyDir: &v1.EmptyDirVolumeSource{},
+		},
+	}
+	pod.Spec.Volumes = append(pod.Spec.Volumes, volume)
+	return pod
+}
+
+func withStatus(phase v1.PodPhase, pod *v1.Pod) *v1.Pod {
+	pod.Status.Phase = phase
+	return pod
+}
+
+func pvc() *v1.PersistentVolumeClaim {
+	return &v1.PersistentVolumeClaim{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      defaultPVCName,
+			Namespace: defaultNS,
+		},
+	}
+}
+
+func withProtectionFinalizer(pvc *v1.PersistentVolumeClaim) *v1.PersistentVolumeClaim {
+	pvc.Finalizers = append(pvc.Finalizers, volumeutil.PVCProtectionFinalizer)
+	return pvc
+}
+
+func deleted(pvc *v1.PersistentVolumeClaim) *v1.PersistentVolumeClaim {
+	pvc.DeletionTimestamp = &metav1.Time{}
+	return pvc
+}
+
+func generateUpdateErrorFunc(t *testing.T, failures int) clienttesting.ReactionFunc {
+	i := 0
+	return func(action clienttesting.Action) (bool, runtime.Object, error) {
+		i++
+		if i <= failures {
+			// Update fails
+			update, ok := action.(clienttesting.UpdateAction)
+
+			if !ok {
+				t.Fatalf("Reactor got non-update action: %+v", action)
+			}
+			acc, _ := meta.Accessor(update.GetObject())
+			return true, nil, apierrors.NewForbidden(update.GetResource().GroupResource(), acc.GetName(), errors.New("Mock error"))
+		}
+		// Update succeeds
+		return false, nil, nil
+	}
+}
+
+func TestPVCProtectionController(t *testing.T) {
+	pvcVer := schema.GroupVersionResource{
+		Group:    v1.GroupName,
+		Version:  "v1",
+		Resource: "persistentvolumeclaims",
+	}
+
+	tests := []struct {
+		name string
+		// Object to insert into fake kubeclient before the test starts.
+		initialObjects []runtime.Object
+		// Optional client reactors.
+		reactors []reaction
+		// PVC event to simulate. This PVC will be automatically added to
+		// initalObjects.
+		updatedPVC *v1.PersistentVolumeClaim
+		// Pod event to simulate. This Pod will be automatically added to
+		// initalObjects.
+		updatedPod *v1.Pod
+		// Pod event to similate. This Pod is *not* added to
+		// initalObjects.
+		deletedPod *v1.Pod
+		// List of expected kubeclient actions that should happen during the
+		// test.
+		expectedActions []clienttesting.Action
+	}{
+		//
+		// PVC events
+		//
+		{
+			name:       "PVC without finalizer -> finalizer is added",
+			updatedPVC: pvc(),
+			expectedActions: []clienttesting.Action{
+				clienttesting.NewUpdateAction(pvcVer, defaultNS, withProtectionFinalizer(pvc())),
+			},
+		},
+		{
+			name:            "PVC with finalizer -> no action",
+			updatedPVC:      withProtectionFinalizer(pvc()),
+			expectedActions: []clienttesting.Action{},
+		},
+		{
+			name:       "saving PVC finalizer fails -> controller retries",
+			updatedPVC: pvc(),
+			reactors: []reaction{
+				{
+					verb:      "update",
+					resource:  "persistentvolumeclaims",
+					reactorfn: generateUpdateErrorFunc(t, 2 /* update fails twice*/),
+				},
+			},
+			expectedActions: []clienttesting.Action{
+				// This fails
+				clienttesting.NewUpdateAction(pvcVer, defaultNS, withProtectionFinalizer(pvc())),
+				// This fails too
+				clienttesting.NewUpdateAction(pvcVer, defaultNS, withProtectionFinalizer(pvc())),
+				// This succeeds
+				clienttesting.NewUpdateAction(pvcVer, defaultNS, withProtectionFinalizer(pvc())),
+			},
+		},
+		{
+			name:       "deleted PVC with finalizer -> finalizer is removed",
+			updatedPVC: deleted(withProtectionFinalizer(pvc())),
+			expectedActions: []clienttesting.Action{
+				clienttesting.NewUpdateAction(pvcVer, defaultNS, deleted(pvc())),
+			},
+		},
+		{
+			name:       "finalizer removal fails -> controller retries",
+			updatedPVC: deleted(withProtectionFinalizer(pvc())),
+			reactors: []reaction{
+				{
+					verb:      "update",
+					resource:  "persistentvolumeclaims",
+					reactorfn: generateUpdateErrorFunc(t, 2 /* update fails twice*/),
+				},
+			},
+			expectedActions: []clienttesting.Action{
+				// Fails
+				clienttesting.NewUpdateAction(pvcVer, defaultNS, deleted(pvc())),
+				// Fails too
+				clienttesting.NewUpdateAction(pvcVer, defaultNS, deleted(pvc())),
+				// Succeeds
+				clienttesting.NewUpdateAction(pvcVer, defaultNS, deleted(pvc())),
+			},
+		},
+		{
+			name: "deleted PVC with finalizer + pods with the PVC exists -> finalizer is not removed",
+			initialObjects: []runtime.Object{
+				withPVC(defaultPVCName, pod()),
+			},
+			updatedPVC:      deleted(withProtectionFinalizer(pvc())),
+			expectedActions: []clienttesting.Action{},
+		},
+		{
+			name: "deleted PVC with finalizer + pods with unrelated PVC and EmptyDir exists -> finalizer is removed",
+			initialObjects: []runtime.Object{
+				withEmptyDir(withPVC("unrelatedPVC", pod())),
+			},
+			updatedPVC: deleted(withProtectionFinalizer(pvc())),
+			expectedActions: []clienttesting.Action{
+				clienttesting.NewUpdateAction(pvcVer, defaultNS, deleted(pvc())),
+			},
+		},
+		{
+			name: "deleted PVC with finalizer + pods with the PVC andis finished -> finalizer is removed",
+			initialObjects: []runtime.Object{
+				withStatus(v1.PodFailed, withPVC(defaultPVCName, pod())),
+			},
+			updatedPVC: deleted(withProtectionFinalizer(pvc())),
+			expectedActions: []clienttesting.Action{
+				clienttesting.NewUpdateAction(pvcVer, defaultNS, deleted(pvc())),
+			},
+		},
+		//
+		// Pod events
+		//
+		{
+			name: "updated running Pod -> no action",
+			initialObjects: []runtime.Object{
+				deleted(withProtectionFinalizer(pvc())),
+			},
+			updatedPod:      withStatus(v1.PodRunning, withPVC(defaultPVCName, pod())),
+			expectedActions: []clienttesting.Action{},
+		},
+		{
+			name: "updated finished Pod -> finalizer is removed",
+			initialObjects: []runtime.Object{
+				deleted(withProtectionFinalizer(pvc())),
+			},
+			updatedPod: withStatus(v1.PodSucceeded, withPVC(defaultPVCName, pod())),
+			expectedActions: []clienttesting.Action{
+				clienttesting.NewUpdateAction(pvcVer, defaultNS, deleted(pvc())),
+			},
+		},
+		{
+			name: "updated unscheduled Pod -> finalizer is removed",
+			initialObjects: []runtime.Object{
+				deleted(withProtectionFinalizer(pvc())),
+			},
+			updatedPod: unscheduled(withPVC(defaultPVCName, pod())),
+			expectedActions: []clienttesting.Action{
+				clienttesting.NewUpdateAction(pvcVer, defaultNS, deleted(pvc())),
+			},
+		},
+		{
+			name: "deleted running Pod -> finalizer is removed",
+			initialObjects: []runtime.Object{
+				deleted(withProtectionFinalizer(pvc())),
+			},
+			deletedPod: withStatus(v1.PodRunning, withPVC(defaultPVCName, pod())),
+			expectedActions: []clienttesting.Action{
+				clienttesting.NewUpdateAction(pvcVer, defaultNS, deleted(pvc())),
+			},
+		},
+	}
+
+	for _, test := range tests {
+		// Create client with initial data
+		objs := test.initialObjects
+		if test.updatedPVC != nil {
+			objs = append(objs, test.updatedPVC)
+		}
+		if test.updatedPod != nil {
+			objs = append(objs, test.updatedPod)
+		}
+		client := fake.NewSimpleClientset(objs...)
+
+		// Create informers
+		informers := informers.NewSharedInformerFactory(client, controller.NoResyncPeriodFunc())
+		pvcInformer := informers.Core().V1().PersistentVolumeClaims()
+		podInformer := informers.Core().V1().Pods()
+
+		// Populate the informers with initial objects so the controller can
+		// Get() and List() it.
+		for _, obj := range objs {
+			switch obj.(type) {
+			case *v1.PersistentVolumeClaim:
+				pvcInformer.Informer().GetStore().Add(obj)
+			case *v1.Pod:
+				podInformer.Informer().GetStore().Add(obj)
+			default:
+				t.Fatalf("Unknown initalObject type: %+v", obj)
+			}
+		}
+
+		// Add reactor to inject test errors.
+		for _, reactor := range test.reactors {
+			client.Fake.PrependReactor(reactor.verb, reactor.resource, reactor.reactorfn)
+		}
+
+		// Create the controller
+		ctrl := NewPVCProtectionController(pvcInformer, podInformer, client)
+
+		// Start the test by simulating an event
+		if test.updatedPVC != nil {
+			ctrl.pvcAddedUpdated(test.updatedPVC)
+		}
+		if test.updatedPod != nil {
+			ctrl.podAddedDeletedUpdated(test.updatedPod, false)
+		}
+		if test.deletedPod != nil {
+			ctrl.podAddedDeletedUpdated(test.deletedPod, true)
+		}
+
+		// Process the controller queue until we get expected results
+		timeout := time.Now().Add(10 * time.Second)
+		lastReportedActionCount := 0
+		for {
+			if time.Now().After(timeout) {
+				t.Errorf("Test %q: timed out", test.name)
+				break
+			}
+			if ctrl.queue.Len() > 0 {
+				glog.V(5).Infof("Test %q: %d events queue, processing one", test.name, ctrl.queue.Len())
+				ctrl.processNextWorkItem()
+			}
+			if ctrl.queue.Len() > 0 {
+				// There is still some work in the queue, process it now
+				continue
+			}
+			currentActionCount := len(client.Actions())
+			if currentActionCount < len(test.expectedActions) {
+				// Do not log evey wait, only when the action count changes.
+				if lastReportedActionCount < currentActionCount {
+					glog.V(5).Infof("Test %q: got %d actions out of %d, waiting for the rest", test.name, currentActionCount, len(test.expectedActions))
+					lastReportedActionCount = currentActionCount
+				}
+				// The test expected more to happen, wait for the actions.
+				// Most probably it's exponential backoff
+				time.Sleep(10 * time.Millisecond)
+				continue
+			}
+			break
+		}
+		actions := client.Actions()
+		for i, action := range actions {
+			if len(test.expectedActions) < i+1 {
+				t.Errorf("Test %q: %d unexpected actions: %+v", test.name, len(actions)-len(test.expectedActions), spew.Sdump(actions[i:]))
+				break
+			}
+
+			expectedAction := test.expectedActions[i]
+			if !reflect.DeepEqual(expectedAction, action) {
+				t.Errorf("Test %q: action %d\nExpected:\n%s\ngot:\n%s", test.name, i, spew.Sdump(expectedAction), spew.Sdump(action))
+			}
+		}
+
+		if len(test.expectedActions) > len(actions) {
+			t.Errorf("Test %q: %d additional expected actions", test.name, len(test.expectedActions)-len(actions))
+			for _, a := range test.expectedActions[len(actions):] {
+				t.Logf("    %+v", a)
+			}
+		}
+
+	}
+}

pkg/volume/util/BUILD

@@ -76,6 +76,7 @@ go_test(
     deps = [
         "//pkg/apis/core/install:go_default_library",
         "//pkg/apis/core/v1/helper:go_default_library",
+        "//vendor/github.com/davecgh/go-spew/spew:go_default_library",
         "//vendor/k8s.io/api/core/v1:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/util/sets:go_default_library",

pkg/volume/util/finalizer.go

@@ -31,3 +31,38 @@ const (
 func IsPVCBeingDeleted(pvc *v1.PersistentVolumeClaim) bool {
 	return pvc.ObjectMeta.DeletionTimestamp != nil
 }
+
+// IsProtectionFinalizerPresent returns true in case PVCProtectionFinalizer is
+// present among the pvc.Finalizers
+func IsProtectionFinalizerPresent(pvc *v1.PersistentVolumeClaim) bool {
+	for _, finalizer := range pvc.Finalizers {
+		if finalizer == PVCProtectionFinalizer {
+			return true
+		}
+	}
+	return false
+}
+
+// RemoveProtectionFinalizer returns pvc without PVCProtectionFinalizer in case
+// it's present in pvc.Finalizers. It expects that pvc is writable (i.e. is not
+// informer's cached copy.)
+func RemoveProtectionFinalizer(pvc *v1.PersistentVolumeClaim) {
+	newFinalizers := make([]string, 0)
+	for _, finalizer := range pvc.Finalizers {
+		if finalizer != PVCProtectionFinalizer {
+			newFinalizers = append(newFinalizers, finalizer)
+		}
+	}
+	if len(newFinalizers) == 0 {
+		// Sanitize for unit tests so we don't need to distinguish empty array
+		// and nil.
+		newFinalizers = nil
+	}
+	pvc.Finalizers = newFinalizers
+}
+
+// AddProtectionFinalizer adds PVCProtectionFinalizer to pvc. It expects that
+// pvc is writable (i.e. is not informer's cached copy.)
+func AddProtectionFinalizer(pvc *v1.PersistentVolumeClaim) {
+	pvc.Finalizers = append(pvc.Finalizers, PVCProtectionFinalizer)
+}

pkg/volume/util/finalizer_test.go

@@ -17,9 +17,11 @@ limitations under the License.
 package util
 
 import (
+	"reflect"
 	"testing"
 	"time"
 
+	"github.com/davecgh/go-spew/spew"
 	"k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 )
@@ -56,3 +58,174 @@ func TestIsPVCBeingDeleted(t *testing.T) {
 		}
 	}
 }
+
+func TestAddProtectionFinalizer(t *testing.T) {
+	tests := []struct {
+		name string
+		pvc  *v1.PersistentVolumeClaim
+		want *v1.PersistentVolumeClaim
+	}{
+		{
+			"PVC without finalizer",
+			&v1.PersistentVolumeClaim{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:      "pvc",
+					Namespace: "ns",
+				},
+			},
+			&v1.PersistentVolumeClaim{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:       "pvc",
+					Namespace:  "ns",
+					Finalizers: []string{PVCProtectionFinalizer},
+				},
+			},
+		},
+		{
+			"PVC with some finalizers",
+			&v1.PersistentVolumeClaim{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:       "pvc",
+					Namespace:  "ns",
+					Finalizers: []string{"1", "2", "3", PVCProtectionFinalizer + "suffix", "prefix" + PVCProtectionFinalizer},
+				},
+			},
+			&v1.PersistentVolumeClaim{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:       "pvc",
+					Namespace:  "ns",
+					Finalizers: []string{"1", "2", "3", PVCProtectionFinalizer + "suffix", "prefix" + PVCProtectionFinalizer, PVCProtectionFinalizer},
+				},
+			},
+		},
+	}
+	for _, test := range tests {
+		got := test.pvc.DeepCopy()
+		AddProtectionFinalizer(got)
+		if !reflect.DeepEqual(got, test.want) {
+			t.Errorf("Test %q: expected:\n%s\n\ngot:\n%s", test.name, spew.Sdump(test.want), spew.Sdump(got))
+		}
+	}
+}
+
+func TestRemoveProtectionFinalizer(t *testing.T) {
+	tests := []struct {
+		name string
+		pvc  *v1.PersistentVolumeClaim
+		want *v1.PersistentVolumeClaim
+	}{
+		{
+			"PVC without finalizer",
+			&v1.PersistentVolumeClaim{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:      "pvc",
+					Namespace: "ns",
+				},
+			},
+			&v1.PersistentVolumeClaim{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:      "pvc",
+					Namespace: "ns",
+				},
+			},
+		},
+		{
+			"PVC with finalizer",
+			&v1.PersistentVolumeClaim{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:       "pvc",
+					Namespace:  "ns",
+					Finalizers: []string{PVCProtectionFinalizer},
+				},
+			},
+			&v1.PersistentVolumeClaim{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:      "pvc",
+					Namespace: "ns",
+				},
+			},
+		},
+		{
+			"PVC with many finalizers",
+			&v1.PersistentVolumeClaim{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:       "pvc",
+					Namespace:  "ns",
+					Finalizers: []string{"1", "2", "3", PVCProtectionFinalizer + "suffix", "prefix" + PVCProtectionFinalizer, PVCProtectionFinalizer},
+				},
+			},
+			&v1.PersistentVolumeClaim{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:       "pvc",
+					Namespace:  "ns",
+					Finalizers: []string{"1", "2", "3", PVCProtectionFinalizer + "suffix", "prefix" + PVCProtectionFinalizer},
+				},
+			},
+		},
+	}
+	for _, test := range tests {
+		got := test.pvc.DeepCopy()
+		RemoveProtectionFinalizer(got)
+		if !reflect.DeepEqual(got, test.want) {
+			t.Errorf("Test %q: expected:\n%s\n\ngot:\n%s", test.name, spew.Sdump(test.want), spew.Sdump(got))
+		}
+	}
+}
+
+func TestIsProtectionFinalizerPresent(t *testing.T) {
+	tests := []struct {
+		name string
+		pvc  *v1.PersistentVolumeClaim
+		want bool
+	}{
+		{
+			"PVC without finalizer",
+			&v1.PersistentVolumeClaim{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:      "pvc",
+					Namespace: "ns",
+				},
+			},
+			false,
+		},
+		{
+			"PVC with many unrelated finalizers",
+			&v1.PersistentVolumeClaim{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:       "pvc",
+					Namespace:  "ns",
+					Finalizers: []string{"1", "2", "3", PVCProtectionFinalizer + "suffix", "prefix" + PVCProtectionFinalizer},
+				},
+			},
+			false,
+		},
+		{
+			"PVC with many finalizers",
+			&v1.PersistentVolumeClaim{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:       "pvc",
+					Namespace:  "ns",
+					Finalizers: []string{"1", "2", "3", PVCProtectionFinalizer + "suffix", "prefix" + PVCProtectionFinalizer, PVCProtectionFinalizer},
+				},
+			},
+			true,
+		},
+		{
+			"PVC with finalizer",
+			&v1.PersistentVolumeClaim{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:       "pvc",
+					Namespace:  "ns",
+					Finalizers: []string{PVCProtectionFinalizer},
+				},
+			},
+			true,
+		},
+	}
+	for _, test := range tests {
+		got := IsProtectionFinalizerPresent(test.pvc)
+		if got != test.want {
+			t.Errorf("Test %q: expected %v, got %v", test.name, test.want, got)
+		}
+	}
+}