k3s/test/e2e/persistent_volumes.go

/*
Copyright 2015 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 e2e

import (
	"fmt"
	"time"

	. "github.com/onsi/ginkgo"
	. "github.com/onsi/gomega"
	apierrs "k8s.io/kubernetes/pkg/api/errors"
	"k8s.io/kubernetes/pkg/api/resource"
	"k8s.io/kubernetes/pkg/api/v1"
	"k8s.io/kubernetes/pkg/apimachinery/registered"
	metav1 "k8s.io/kubernetes/pkg/apis/meta/v1"
	clientset "k8s.io/kubernetes/pkg/client/clientset_generated/clientset"
	"k8s.io/kubernetes/pkg/types"
	"k8s.io/kubernetes/pkg/volume/util/volumehelper"
	"k8s.io/kubernetes/test/e2e/framework"
)

// Map of all PVs used in the multi pv-pvc tests. The key is the PV's name, which is
// guaranteed to be unique. The value is {} (empty struct) since we're only interested
// in the PV's name and if it is present. We must always Get the pv object before
// referencing any of its values, eg its ClaimRef.
type pvval struct{}
type pvmap map[string]pvval

// Map of all PVCs used in the multi pv-pvc tests. The key is "namespace/pvc.Name". The
// value is {} (empty struct) since we're only interested in the PVC's name and if it is
// present. We must always Get the pvc object before referencing any of its values, eg.
// its VolumeName.
// Note: It's unsafe to add keys to a map in a loop. Their insertion in the map is
//   unpredictable and can result in the same key being iterated over again.
type pvcval struct{}
type pvcmap map[types.NamespacedName]pvcval

// Delete the nfs-server pod. Only done once per KubeDescription().
func nfsServerPodCleanup(c clientset.Interface, config VolumeTestConfig) {
	defer GinkgoRecover()

	podClient := c.Core().Pods(config.namespace)

	if config.serverImage != "" {
		podName := config.prefix + "-server"
		err := podClient.Delete(podName, nil)
		Expect(err).NotTo(HaveOccurred())
	}
}

// Cleanup up pvs and pvcs in multi-pv-pvc test cases. All entries found in the pv and
// claims maps are deleted.
// Note: this is the only code that deletes PV objects.
func pvPvcCleanup(c clientset.Interface, ns string, pvols pvmap, claims pvcmap) {

	if c != nil && len(ns) > 0 {
		for pvcKey := range claims {
			_, err := c.Core().PersistentVolumeClaims(pvcKey.Namespace).Get(pvcKey.Name, metav1.GetOptions{})
			if !apierrs.IsNotFound(err) {
				Expect(err).NotTo(HaveOccurred())
				framework.Logf("   deleting PVC %v ...", pvcKey)
				err = c.Core().PersistentVolumeClaims(pvcKey.Namespace).Delete(pvcKey.Name, nil)
				Expect(err).NotTo(HaveOccurred())
				framework.Logf("   deleted  PVC %v", pvcKey)
			}
			delete(claims, pvcKey)
		}

		for name := range pvols {
			_, err := c.Core().PersistentVolumes().Get(name, metav1.GetOptions{})
			if !apierrs.IsNotFound(err) {
				Expect(err).NotTo(HaveOccurred())
				framework.Logf("   deleting PV %v ...", name)
				err = c.Core().PersistentVolumes().Delete(name, nil)
				Expect(err).NotTo(HaveOccurred())
				framework.Logf("   deleted  PV %v", name)
			}
			delete(pvols, name)
		}
	}
}

// Delete the PVC and wait for the PV to become Available again. Validate that the PV
// has recycled (assumption here about reclaimPolicy). Caller tells this func which
// phase value to expect for the pv bound to the to-be-deleted claim.
func deletePVCandValidatePV(c clientset.Interface, ns string, pvc *v1.PersistentVolumeClaim, pv *v1.PersistentVolume, expctPVPhase v1.PersistentVolumePhase) {

	pvname := pvc.Spec.VolumeName
	framework.Logf("Deleting PVC %v to trigger recycling of PV %v", pvc.Name, pvname)

	err := c.Core().PersistentVolumeClaims(ns).Delete(pvc.Name, nil)
	Expect(err).NotTo(HaveOccurred())

	// Check that the PVC is really deleted.
	pvc, err = c.Core().PersistentVolumeClaims(ns).Get(pvc.Name, metav1.GetOptions{})
	Expect(apierrs.IsNotFound(err)).To(BeTrue())

	// Wait for the PV's phase to return to the expected Phase
	framework.Logf("Waiting for recycling process to complete.")
	err = framework.WaitForPersistentVolumePhase(expctPVPhase, c, pv.Name, 1*time.Second, 300*time.Second)
	Expect(err).NotTo(HaveOccurred())

	// examine the pv's ClaimRef and UID and compare to expected values
	pv, err = c.Core().PersistentVolumes().Get(pv.Name, metav1.GetOptions{})
	Expect(err).NotTo(HaveOccurred())
	cr := pv.Spec.ClaimRef
	if expctPVPhase == v1.VolumeAvailable {
		if cr != nil { // may be ok if cr != nil
			Expect(len(cr.UID)).To(BeZero())
		}
	} else if expctPVPhase == v1.VolumeBound {
		Expect(cr).NotTo(BeNil())
		Expect(len(cr.UID)).NotTo(BeZero())
	}

	framework.Logf("PV %v now in %q phase", pv.Name, expctPVPhase)
}

// Wraps deletePVCandValidatePV() by calling the function in a loop over the PV map. Only
// bound PVs are deleted. Validates that the claim was deleted and the PV is Available.
// Note: if there are more claims than pvs then some of the remaining claims will bind to
//   the just-made-available pvs.
func deletePVCandValidatePVGroup(c clientset.Interface, ns string, pvols pvmap, claims pvcmap) {

	var boundPVs, deletedPVCs int
	var expctPVPhase v1.PersistentVolumePhase

	for pvName := range pvols {
		pv, err := c.Core().PersistentVolumes().Get(pvName, metav1.GetOptions{})
		Expect(apierrs.IsNotFound(err)).To(BeFalse())
		cr := pv.Spec.ClaimRef
		// if pv is bound then delete the pvc it is bound to
		if cr != nil && len(cr.Name) > 0 {
			boundPVs++
			// Assert bound PVC is tracked in this test. Failing this might
			// indicate external PVCs interfering with the test.
			pvcKey := makePvcKey(ns, cr.Name)
			_, found := claims[pvcKey]
			Expect(found).To(BeTrue())
			pvc, err := c.Core().PersistentVolumeClaims(ns).Get(cr.Name, metav1.GetOptions{})
			Expect(apierrs.IsNotFound(err)).To(BeFalse())

			// what Phase do we expect the PV that was bound to the claim to
			// be in after that claim is deleted?
			expctPVPhase = v1.VolumeAvailable
			if len(claims) > len(pvols) {
				// there are excess pvcs so expect the previously bound
				// PV to become bound again
				expctPVPhase = v1.VolumeBound
			}

			deletePVCandValidatePV(c, ns, pvc, pv, expctPVPhase)
			delete(claims, pvcKey)
			deletedPVCs++
		}
	}
	Expect(boundPVs).To(Equal(deletedPVCs))
}

// create the PV resource. Fails test on error.
func createPV(c clientset.Interface, pv *v1.PersistentVolume) *v1.PersistentVolume {

	pv, err := c.Core().PersistentVolumes().Create(pv)
	Expect(err).NotTo(HaveOccurred())
	return pv
}

// create the PVC resource. Fails test on error.
func createPVC(c clientset.Interface, ns string, pvc *v1.PersistentVolumeClaim) *v1.PersistentVolumeClaim {

	pvc, err := c.Core().PersistentVolumeClaims(ns).Create(pvc)
	Expect(err).NotTo(HaveOccurred())
	return pvc
}

// Create a PVC followed by the PV based on the passed in nfs-server ip and
// namespace. If the "preBind" bool is true then pre-bind the PV to the PVC
// via the PV's ClaimRef. Return the pv and pvc to reflect the created objects.
// Note: in the pre-bind case the real PVC name, which is generated, is not
//   known until after the PVC is instantiated. This is why the pvc is created
//   before the pv.
func createPVCPV(c clientset.Interface, serverIP, ns string, preBind bool) (*v1.PersistentVolume, *v1.PersistentVolumeClaim) {

	var bindTo *v1.PersistentVolumeClaim
	var preBindMsg string

	// make the pvc definition first
	pvc := makePersistentVolumeClaim(ns)
	if preBind {
		preBindMsg = " pre-bound"
		bindTo = pvc
	}
	// make the pv spec
	pv := makePersistentVolume(serverIP, bindTo)

	By(fmt.Sprintf("Creating a PVC followed by a%s PV", preBindMsg))
	// instantiate the pvc
	pvc = createPVC(c, ns, pvc)

	// instantiate the pv, handle pre-binding by ClaimRef if needed
	if preBind {
		pv.Spec.ClaimRef.Name = pvc.Name
	}
	pv = createPV(c, pv)

	return pv, pvc
}

// Create a PV followed by the PVC based on the passed in nfs-server ip and
// namespace. If the "preBind" bool is true then pre-bind the PVC to the PV
// via the PVC's VolumeName. Return the pv and pvc to reflect the created
// objects.
// Note: in the pre-bind case the real PV name, which is generated, is not
//   known until after the PV is instantiated. This is why the pv is created
//   before the pvc.
func createPVPVC(c clientset.Interface, serverIP, ns string, preBind bool) (*v1.PersistentVolume, *v1.PersistentVolumeClaim) {

	preBindMsg := ""
	if preBind {
		preBindMsg = " pre-bound"
	}
	framework.Logf("Creating a PV followed by a%s PVC", preBindMsg)

	// make the pv and pvc definitions
	pv := makePersistentVolume(serverIP, nil)
	pvc := makePersistentVolumeClaim(ns)

	// instantiate the pv
	pv = createPV(c, pv)
	// instantiate the pvc, handle pre-binding by VolumeName if needed
	if preBind {
		pvc.Spec.VolumeName = pv.Name
	}
	pvc = createPVC(c, ns, pvc)

	return pv, pvc
}

// Create the desired number of PVs and PVCs and return them in separate maps. If the
// number of PVs != the number of PVCs then the min of those two counts is the number of
// PVs expected to bind.
func createPVsPVCs(numpvs, numpvcs int, c clientset.Interface, ns, serverIP string) (pvmap, pvcmap) {

	var i int
	var pv *v1.PersistentVolume
	var pvc *v1.PersistentVolumeClaim
	pvMap := make(pvmap, numpvs)
	pvcMap := make(pvcmap, numpvcs)

	var extraPVs, extraPVCs int
	extraPVs = numpvs - numpvcs
	if extraPVs < 0 {
		extraPVCs = -extraPVs
		extraPVs = 0
	}
	pvsToCreate := numpvs - extraPVs // want the min(numpvs, numpvcs)

	// create pvs and pvcs
	for i = 0; i < pvsToCreate; i++ {
		pv, pvc = createPVPVC(c, serverIP, ns, false)
		pvMap[pv.Name] = pvval{}
		pvcMap[makePvcKey(ns, pvc.Name)] = pvcval{}
	}

	// create extra pvs or pvcs as needed
	for i = 0; i < extraPVs; i++ {
		pv = makePersistentVolume(serverIP, nil)
		pv = createPV(c, pv)
		pvMap[pv.Name] = pvval{}
	}
	for i = 0; i < extraPVCs; i++ {
		pvc = makePersistentVolumeClaim(ns)
		pvc = createPVC(c, ns, pvc)
		pvcMap[makePvcKey(ns, pvc.Name)] = pvcval{}
	}

	return pvMap, pvcMap
}

// Wait for the pv and pvc to bind to each other.
func waitOnPVandPVC(c clientset.Interface, ns string, pv *v1.PersistentVolume, pvc *v1.PersistentVolumeClaim) {

	// Wait for newly created PVC to bind to the PV
	framework.Logf("Waiting for PV %v to bind to PVC %v", pv.Name, pvc.Name)
	err := framework.WaitForPersistentVolumeClaimPhase(v1.ClaimBound, c, ns, pvc.Name, 3*time.Second, 300*time.Second)
	Expect(err).NotTo(HaveOccurred())

	// Wait for PersistentVolume.Status.Phase to be Bound, which it should be
	// since the PVC is already bound.
	err = framework.WaitForPersistentVolumePhase(v1.VolumeBound, c, pv.Name, 3*time.Second, 300*time.Second)
	Expect(err).NotTo(HaveOccurred())

	// Re-get the pv and pvc objects
	pv, err = c.Core().PersistentVolumes().Get(pv.Name, metav1.GetOptions{})
	Expect(err).NotTo(HaveOccurred())

	// Re-get the pvc and
	pvc, err = c.Core().PersistentVolumeClaims(ns).Get(pvc.Name, metav1.GetOptions{})
	Expect(err).NotTo(HaveOccurred())

	// The pv and pvc are both bound, but to each other?
	// Check that the PersistentVolume.ClaimRef matches the PVC
	Expect(pv.Spec.ClaimRef).NotTo(BeNil())
	Expect(pv.Spec.ClaimRef.Name).To(Equal(pvc.Name))
	Expect(pvc.Spec.VolumeName).To(Equal(pv.Name))
	Expect(pv.Spec.ClaimRef.UID).To(Equal(pvc.UID))
}

// Search for bound PVs and PVCs by examining pvols for non-nil claimRefs.
// NOTE: Each iteration waits for a maximum of 3 minutes per PV and, if the PV is bound,
//   up to 3 minutes for the PVC. When the number of PVs != number of PVCs, this can lead
//   to situations where the maximum wait times are reached several times in succession,
//   extending test time. Thus, it is recommended to keep the delta between PVs and PVCs
//   small.
func waitAndVerifyBinds(c clientset.Interface, ns string, pvols pvmap, claims pvcmap, testExpected bool) {

	var actualBinds int
	expectedBinds := len(pvols)
	if expectedBinds > len(claims) { // want the min of # pvs or #pvcs
		expectedBinds = len(claims)
	}

	for pvName := range pvols {
		err := framework.WaitForPersistentVolumePhase(v1.VolumeBound, c, pvName, 3*time.Second, 180*time.Second)
		if err != nil && len(pvols) > len(claims) {
			framework.Logf("WARN: pv %v is not bound after max wait", pvName)
			framework.Logf("      This may be ok since there are more pvs than pvcs")
			continue
		}
		Expect(err).NotTo(HaveOccurred())

		pv, err := c.Core().PersistentVolumes().Get(pvName, metav1.GetOptions{})
		Expect(err).NotTo(HaveOccurred())
		if cr := pv.Spec.ClaimRef; cr != nil && len(cr.Name) > 0 {
			// Assert bound pvc is a test resource. Failing assertion could
			// indicate non-test PVC interference or a bug in the test
			pvcKey := makePvcKey(ns, cr.Name)
			_, found := claims[pvcKey]
			Expect(found).To(BeTrue())

			err = framework.WaitForPersistentVolumeClaimPhase(v1.ClaimBound, c, ns, cr.Name, 3*time.Second, 180*time.Second)
			Expect(err).NotTo(HaveOccurred())
			actualBinds++
		}
	}

	if testExpected {
		Expect(actualBinds).To(Equal(expectedBinds))
	}
}

// Test the pod's exit code to be zero.
func testPodSuccessOrFail(c clientset.Interface, ns string, pod *v1.Pod) {

	By("Pod should terminate with exitcode 0 (success)")
	err := framework.WaitForPodSuccessInNamespace(c, pod.Name, ns)
	Expect(err).NotTo(HaveOccurred())
	framework.Logf("Pod %v succeeded ", pod.Name)
}

// Delete the passed in pod.
func deletePod(f *framework.Framework, c clientset.Interface, ns string, pod *v1.Pod) {

	framework.Logf("Deleting pod %v", pod.Name)
	err := c.Core().Pods(ns).Delete(pod.Name, nil)
	Expect(err).NotTo(HaveOccurred())

	// Wait for pod to terminate.  Expect apierr NotFound
	err = f.WaitForPodTerminated(pod.Name, "")
	Expect(err).To(HaveOccurred())
	Expect(apierrs.IsNotFound(err)).To(BeTrue())

	framework.Logf("Ignore \"not found\" error above. Pod %v successfully deleted", pod.Name)
}

// Create the test pod, wait for (hopefully) success, and then delete the pod.
func createWaitAndDeletePod(f *framework.Framework, c clientset.Interface, ns string, claimName string) {

	framework.Logf("Creating nfs test pod")

	// Make pod spec
	pod := makeWritePod(ns, claimName)

	// Instantiate pod (Create)
	runPod, err := c.Core().Pods(ns).Create(pod)
	Expect(err).NotTo(HaveOccurred())
	Expect(runPod).NotTo(BeNil())

	defer deletePod(f, c, ns, runPod)

	// Wait for the test pod to complete its lifecycle
	testPodSuccessOrFail(c, ns, runPod)
}

// Validate PV/PVC, create and verify writer pod, delete the PVC, and validate the PV's
// phase. Note: the PV is deleted in the AfterEach, not here.
func completeTest(f *framework.Framework, c clientset.Interface, ns string, pv *v1.PersistentVolume, pvc *v1.PersistentVolumeClaim) {

	// 1. verify that the PV and PVC have binded correctly
	By("Validating the PV-PVC binding")
	waitOnPVandPVC(c, ns, pv, pvc)

	// 2. create the nfs writer pod, test if the write was successful,
	//    then delete the pod and verify that it was deleted
	By("Checking pod has write access to PersistentVolume")
	createWaitAndDeletePod(f, c, ns, pvc.Name)

	// 3. delete the PVC, wait for PV to become "Available"
	By("Deleting the PVC to invoke the recycler")
	deletePVCandValidatePV(c, ns, pvc, pv, v1.VolumeAvailable)
}

// Validate pairs of PVs and PVCs, create and verify writer pod, delete PVC and validate
// PV. Ensure each step succeeds.
// Note: the PV is deleted in the AfterEach, not here.
// Note: this func is serialized, we wait for each pod to be deleted before creating the
//   next pod. Adding concurrency is a TODO item.
// Note: this func is called recursively when there are more claims than pvs.
func completeMultiTest(f *framework.Framework, c clientset.Interface, ns string, pvols pvmap, claims pvcmap) {

	// 1. verify each PV permits write access to a client pod
	By("Checking pod has write access to PersistentVolumes")
	for pvcKey := range claims {
		pvc, err := c.Core().PersistentVolumeClaims(pvcKey.Namespace).Get(pvcKey.Name, metav1.GetOptions{})
		Expect(err).NotTo(HaveOccurred())
		if len(pvc.Spec.VolumeName) == 0 {
			continue // claim is not bound
		}
		// sanity test to ensure our maps are in sync
		_, found := pvols[pvc.Spec.VolumeName]
		Expect(found).To(BeTrue())
		// TODO: currently a serialized test of each PV
		createWaitAndDeletePod(f, c, pvcKey.Namespace, pvcKey.Name)
	}

	// 2. delete each PVC, wait for its bound PV to become "Available"
	By("Deleting PVCs to invoke recycler")
	deletePVCandValidatePVGroup(c, ns, pvols, claims)
}

var _ = framework.KubeDescribe("PersistentVolumes", func() {

	// global vars for the Context()s and It()'s below
	f := framework.NewDefaultFramework("pv")
	var c clientset.Interface
	var ns string
	var NFSconfig VolumeTestConfig
	var serverIP string
	var nfsServerPod *v1.Pod

	// config for the nfs-server pod in the default namespace
	NFSconfig = VolumeTestConfig{
		namespace:   v1.NamespaceDefault,
		prefix:      "nfs",
		serverImage: "gcr.io/google_containers/volume-nfs:0.7",
		serverPorts: []int{2049},
		serverArgs:  []string{"-G", "777", "/exports"},
	}

	BeforeEach(func() {
		c = f.ClientSet
		ns = f.Namespace.Name

		// If it doesn't exist, create the nfs server pod in the "default" ns.
		// The "default" ns is used so that individual tests can delete their
		// ns without impacting the nfs-server pod.
		if nfsServerPod == nil {
			nfsServerPod = startVolumeServer(c, NFSconfig)
			serverIP = nfsServerPod.Status.PodIP
			framework.Logf("NFS server IP address: %v", serverIP)
		}
	})

	// Execute after *all* the tests have run
	AddCleanupAction(func() {
		if nfsServerPod != nil && c != nil {
			framework.Logf("AfterSuite: deleting nfs-server pod: %v", nfsServerPod.Name)
			nfsServerPodCleanup(c, NFSconfig)
			nfsServerPod = nil
		}
	})

	Context("with Single PV - PVC pairs", func() {

		var pv *v1.PersistentVolume
		var pvc *v1.PersistentVolumeClaim

		// Note: this is the only code where the pv is deleted.
		AfterEach(func() {
			if c != nil && len(ns) > 0 {
				if pvc != nil && len(pvc.Name) > 0 {
					_, err := c.Core().PersistentVolumeClaims(ns).Get(pvc.Name, metav1.GetOptions{})
					if !apierrs.IsNotFound(err) {
						Expect(err).NotTo(HaveOccurred())
						framework.Logf("AfterEach: deleting PVC %v", pvc.Name)
						err = c.Core().PersistentVolumeClaims(ns).Delete(pvc.Name, nil)
						Expect(err).NotTo(HaveOccurred())
						framework.Logf("AfterEach: deleted PVC %v", pvc.Name)
					}
				}
				pvc = nil

				if pv != nil && len(pv.Name) > 0 {
					_, err := c.Core().PersistentVolumes().Get(pv.Name, metav1.GetOptions{})
					if !apierrs.IsNotFound(err) {
						Expect(err).NotTo(HaveOccurred())
						framework.Logf("AfterEach: deleting PV %v", pv.Name)
						err := c.Core().PersistentVolumes().Delete(pv.Name, nil)
						Expect(err).NotTo(HaveOccurred())
						framework.Logf("AfterEach: deleted PV %v", pv.Name)
					}
				}
				pv = nil
			}
		})

		// Individual tests follow:
		//
		// Create an nfs PV, then a claim that matches the PV, and a pod that
		// contains the claim. Verify that the PV and PVC bind correctly, and
		// that the pod can write to the nfs volume.
		It("should create a non-pre-bound PV and PVC: test write access [Flaky]", func() {
			pv, pvc = createPVPVC(c, serverIP, ns, false)
			completeTest(f, c, ns, pv, pvc)
		})

		// Create a claim first, then a nfs PV that matches the claim, and a
		// pod that contains the claim. Verify that the PV and PVC bind
		// correctly, and that the pod can write to the nfs volume.
		It("create a PVC and non-pre-bound PV: test write access [Flaky]", func() {
			pv, pvc = createPVCPV(c, serverIP, ns, false)
			completeTest(f, c, ns, pv, pvc)
		})

		// Create a claim first, then a pre-bound nfs PV that matches the claim,
		// and a pod that contains the claim. Verify that the PV and PVC bind
		// correctly, and that the pod can write to the nfs volume.
		It("create a PVC and a pre-bound PV: test write access [Flaky]", func() {
			pv, pvc = createPVCPV(c, serverIP, ns, true)
			completeTest(f, c, ns, pv, pvc)
		})

		// Create a nfs PV first, then a pre-bound PVC that matches the PV,
		// and a pod that contains the claim. Verify that the PV and PVC bind
		// correctly, and that the pod can write to the nfs volume.
		It("create a PV and a pre-bound PVC: test write access [Flaky]", func() {
			pv, pvc = createPVPVC(c, serverIP, ns, true)
			completeTest(f, c, ns, pv, pvc)
		})
	})

	// Create multiple pvs and pvcs, all in the same namespace. The PVs-PVCs are
	// verified to bind, though it's not known in advanced which PV will bind to
	// which claim. For each pv-pvc pair create a pod that writes to the nfs mount.
	// Note: when the number of PVs exceeds the number of PVCs the max binding wait
	//   time will occur for each PV in excess. This is expected but the delta
	//   should be kept small so that the tests aren't unnecessarily slow.
	// Note: future tests may wish to incorporate the following:
	//   a) pre-binding, b) create pvcs before pvs, c) create pvcs and pods
	//   in different namespaces.
	Context("with multiple PVs and PVCs all in same ns", func() {

		// define the maximum number of PVs and PVCs supported by these tests
		const maxNumPVs = 10
		const maxNumPVCs = 10
		// create the pv and pvc maps to be reused in the It blocks
		pvols := make(pvmap, maxNumPVs)
		claims := make(pvcmap, maxNumPVCs)

		AfterEach(func() {
			framework.Logf("AfterEach: deleting %v PVCs and %v PVs...", len(claims), len(pvols))
			pvPvcCleanup(c, ns, pvols, claims)
		})

		// Create 2 PVs and 4 PVCs.
		// Note: PVs are created before claims and no pre-binding
		It("should create 2 PVs and 4 PVCs: test write access[Flaky]", func() {
			numPVs, numPVCs := 2, 4
			pvols, claims = createPVsPVCs(numPVs, numPVCs, c, ns, serverIP)
			waitAndVerifyBinds(c, ns, pvols, claims, true)
			completeMultiTest(f, c, ns, pvols, claims)
		})

		// Create 3 PVs and 3 PVCs.
		// Note: PVs are created before claims and no pre-binding
		It("should create 3 PVs and 3 PVCs: test write access[Flaky]", func() {
			numPVs, numPVCs := 3, 3
			pvols, claims = createPVsPVCs(numPVs, numPVCs, c, ns, serverIP)
			waitAndVerifyBinds(c, ns, pvols, claims, true)
			completeMultiTest(f, c, ns, pvols, claims)
		})

		// Create 4 PVs and 2 PVCs.
		// Note: PVs are created before claims and no pre-binding.
		It("should create 4 PVs and 2 PVCs: test write access[Flaky]", func() {
			numPVs, numPVCs := 4, 2
			pvols, claims = createPVsPVCs(numPVs, numPVCs, c, ns, serverIP)
			waitAndVerifyBinds(c, ns, pvols, claims, true)
			completeMultiTest(f, c, ns, pvols, claims)
		})
	})
})

// Return a pvckey struct.
func makePvcKey(ns, name string) types.NamespacedName {
	return types.NamespacedName{Namespace: ns, Name: name}
}

// Returns a PV definition based on the nfs server IP. If the PVC is not nil
// then the PV is defined with a ClaimRef which includes the PVC's namespace.
// If the PVC is nil then the PV is not defined with a ClaimRef.
// Note: the passed-in claim does not have a name until it is created
//   (instantiated) and thus the PV's ClaimRef cannot be completely filled-in in
//   this func. Therefore, the ClaimRef's name is added later in
//   createPVCPV.
func makePersistentVolume(serverIP string, pvc *v1.PersistentVolumeClaim) *v1.PersistentVolume {
	// Specs are expected to match this test's PersistentVolumeClaim

	var claimRef *v1.ObjectReference

	if pvc != nil {
		claimRef = &v1.ObjectReference{
			Name:      pvc.Name,
			Namespace: pvc.Namespace,
		}
	}

	return &v1.PersistentVolume{
		ObjectMeta: v1.ObjectMeta{
			GenerateName: "nfs-",
			Annotations: map[string]string{
				volumehelper.VolumeGidAnnotationKey: "777",
			},
		},
		Spec: v1.PersistentVolumeSpec{
			PersistentVolumeReclaimPolicy: v1.PersistentVolumeReclaimRecycle,
			Capacity: v1.ResourceList{
				v1.ResourceName(v1.ResourceStorage): resource.MustParse("2Gi"),
			},
			PersistentVolumeSource: v1.PersistentVolumeSource{
				NFS: &v1.NFSVolumeSource{
					Server:   serverIP,
					Path:     "/exports",
					ReadOnly: false,
				},
			},
			AccessModes: []v1.PersistentVolumeAccessMode{
				v1.ReadWriteOnce,
				v1.ReadOnlyMany,
				v1.ReadWriteMany,
			},
			ClaimRef: claimRef,
		},
	}
}

// Returns a PVC definition based on the namespace.
// Note: if this PVC is intended to be pre-bound to a PV, whose name is not
//   known until the PV is instantiated, then the func createPVPVC will add
//   pvc.Spec.VolumeName to this claim.
func makePersistentVolumeClaim(ns string) *v1.PersistentVolumeClaim {
	// Specs are expected to match this test's PersistentVolume

	return &v1.PersistentVolumeClaim{
		ObjectMeta: v1.ObjectMeta{
			GenerateName: "pvc-",
			Namespace:    ns,
		},
		Spec: v1.PersistentVolumeClaimSpec{
			AccessModes: []v1.PersistentVolumeAccessMode{
				v1.ReadWriteOnce,
				v1.ReadOnlyMany,
				v1.ReadWriteMany,
			},
			Resources: v1.ResourceRequirements{
				Requests: v1.ResourceList{
					v1.ResourceName(v1.ResourceStorage): resource.MustParse("1Gi"),
				},
			},
		},
	}
}

// Returns a pod definition based on the namespace. The pod references the PVC's
// name.
func makeWritePod(ns string, pvcName string) *v1.Pod {
	// Prepare pod that mounts the NFS volume again and
	// checks that /mnt/index.html was scrubbed there

	var isPrivileged bool = true
	return &v1.Pod{
		TypeMeta: metav1.TypeMeta{
			Kind:       "Pod",
			APIVersion: registered.GroupOrDie(v1.GroupName).GroupVersion.String(),
		},
		ObjectMeta: v1.ObjectMeta{
			GenerateName: "write-pod-",
			Namespace:    ns,
		},
		Spec: v1.PodSpec{
			Containers: []v1.Container{
				{
					Name:    "write-pod",
					Image:   "gcr.io/google_containers/busybox:1.24",
					Command: []string{"/bin/sh"},
					Args:    []string{"-c", "touch /mnt/SUCCESS && (id -G | grep -E '\\b777\\b')"},
					VolumeMounts: []v1.VolumeMount{
						{
							Name:      "nfs-pvc",
							MountPath: "/mnt",
						},
					},
					SecurityContext: &v1.SecurityContext{
						Privileged: &isPrivileged,
					},
				},
			},
			RestartPolicy: v1.RestartPolicyOnFailure,
			Volumes: []v1.Volume{
				{
					Name: "nfs-pvc",
					VolumeSource: v1.VolumeSource{
						PersistentVolumeClaim: &v1.PersistentVolumeClaimVolumeSource{
							ClaimName: pvcName,
						},
					},
				},
			},
		},
	}
}