Merge pull request #27792 from jeffvance/e2e-prebind

Automatic merge from submit-queue pv e2e refactor and pre-bind test refactored persistentvolume e2e so that multiple It() tests can be run. Added one test case for pre-binding, but the overall structure of the test should allow additional test cases to be more easily added.
2025-11-03 19:58:17 +00:00 · 2016-08-04 05:26:43 -07:00
parent 16454277aa 86578b2e2f
commit b9e808622d
1 changed files with 406 additions and 90 deletions
--- a/test/e2e/persistent_volumes.go
+++ b/test/e2e/persistent_volumes.go
@@ -18,10 +18,12 @@ package e2e

 import (
 	"encoding/json"
+	"fmt"
 	"time"

 	. "github.com/onsi/ginkgo"
 	"k8s.io/kubernetes/pkg/api"
+	apierrs "k8s.io/kubernetes/pkg/api/errors"
 	"k8s.io/kubernetes/pkg/api/resource"
 	"k8s.io/kubernetes/pkg/api/testapi"
 	"k8s.io/kubernetes/pkg/api/unversioned"
@@ -29,148 +31,458 @@ import (
 	"k8s.io/kubernetes/test/e2e/framework"
 )

-// Clean both server and client pods.
-func persistentVolumeTestCleanup(client *client.Client, config VolumeTestConfig) {
+// Delete the nfs-server pod.
+func nfsServerPodCleanup(c *client.Client, config VolumeTestConfig) {
 	defer GinkgoRecover()

-	podClient := client.Pods(config.namespace)
+	podClient := c.Pods(config.namespace)

 	if config.serverImage != "" {
-		err := podClient.Delete(config.prefix+"-server", nil)
+		podName := config.prefix + "-server"
+		err := podClient.Delete(podName, nil)
 		if err != nil {
-			framework.Failf("Failed to delete the server pod: %v", err)
+			framework.Logf("Delete of %v pod failed: %v", podName, err)
 		}
 	}
 }

-func deletePersistentVolume(c *client.Client, pv *api.PersistentVolume) {
-	// Delete the PersistentVolume
-	framework.Logf("Deleting PersistentVolume")
+// Delete the PV. Fail test if delete fails.
+func deletePersistentVolume(c *client.Client, pv *api.PersistentVolume) (*api.PersistentVolume, error) {
+
+	if pv == nil {
+		return nil, fmt.Errorf("PV to be deleted is nil")
+	}
+
+	By("Deleting PersistentVolume")
+
+	framework.Logf("Deleting PersistentVolume %v", pv.Name)
 	err := c.PersistentVolumes().Delete(pv.Name)
 	if err != nil {
-		framework.Failf("Delete PersistentVolume failed: %v", err)
+		return pv, fmt.Errorf("Delete() PersistentVolume %v failed: %v", pv.Name, err)
 	}
-	// Wait for PersistentVolume to Delete
-	framework.WaitForPersistentVolumeDeleted(c, pv.Name, 3*time.Second, 30*time.Second)
+
+	// Wait for PersistentVolume to delete
+	deleteDuration := 90 * time.Second
+	err = framework.WaitForPersistentVolumeDeleted(c, pv.Name, 3*time.Second, deleteDuration)
+	if err != nil {
+		return pv, fmt.Errorf("Unable to delete PersistentVolume %s after waiting for %v: %v", pv.Name, deleteDuration, err)
+	}
+
+	return nil, nil // success
+}
+
+// Delete the PVC and wait for the PV to become Available again.
+// Validate that the PV has recycled (assumption here about reclaimPolicy).
+func deletePVCandValidatePV(c *client.Client, ns string, pvc *api.PersistentVolumeClaim, pv *api.PersistentVolume) (*api.PersistentVolume, *api.PersistentVolumeClaim, error) {
+
+	By("Deleting PersistentVolumeClaim to trigger PV Recycling")
+
+	framework.Logf("Deleting PersistentVolumeClaim %v to trigger PV Recycling", pvc.Name)
+	err := c.PersistentVolumeClaims(ns).Delete(pvc.Name)
+	if err != nil {
+		return pv, pvc, fmt.Errorf("Delete of PVC %v failed: %v", pvc.Name, err)
+	}
+
+	// Check that the PVC is really deleted.
+	pvc, err = c.PersistentVolumeClaims(ns).Get(pvc.Name)
+	if err == nil {
+		return pv, pvc, fmt.Errorf("PVC %v deleted yet still exists", pvc.Name)
+	}
+	if !apierrs.IsNotFound(err) {
+		return pv, pvc, fmt.Errorf("Get on deleted PVC %v failed with error other than \"not found\": %v", pvc.Name, err)
+	}
+
+	// Wait for the PV's phase to return to Available
+	framework.Logf("Waiting for recycling process to complete.")
+	err = framework.WaitForPersistentVolumePhase(api.VolumeAvailable, c, pv.Name, 3*time.Second, 300*time.Second)
+	if err != nil {
+		return pv, pvc, fmt.Errorf("Recycling failed: %v", err)
+	}
+
+	// Examine the pv.ClaimRef and UID. Expect nil values.
+	pv, err = c.PersistentVolumes().Get(pv.Name)
+	if err != nil {
+		return pv, pvc, fmt.Errorf("Cannot re-get PersistentVolume %v:", pv.Name)
+	}
+	if pv.Spec.ClaimRef != nil && len(pv.Spec.ClaimRef.UID) > 0 {
+		crJSON, _ := json.Marshal(pv.Spec.ClaimRef)
+		return pv, pvc, fmt.Errorf("Expected PV %v's ClaimRef to be nil, or the claimRef's UID to be blank. Instead claimRef is: %v", pv.Name, string(crJSON))
+	}
+
+	return pv, pvc, nil
+}
+
+// create the PV resource. Fails test on error.
+func createPV(c *client.Client, pv *api.PersistentVolume) (*api.PersistentVolume, error) {
+
+	pv, err := c.PersistentVolumes().Create(pv)
+	if err != nil {
+		return pv, fmt.Errorf("Create PersistentVolume %v failed: %v", pv.Name, err)
+	}
+
+	return pv, nil
+}
+
+// create the PVC resource. Fails test on error.
+func createPVC(c *client.Client, ns string, pvc *api.PersistentVolumeClaim) (*api.PersistentVolumeClaim, error) {
+
+	pvc, err := c.PersistentVolumeClaims(ns).Create(pvc)
+	if err != nil {
+		return pvc, fmt.Errorf("Create PersistentVolumeClaim %v failed: %v", pvc.Name, err)
+	}
+
+	return pvc, nil
+}
+
+// Create a PV and PVC based on the passed in nfs-server ip and namespace.
+// There are 4 combinations, 3 of which are supported here:
+//   1) prebind and create pvc first
+//   2) no prebind and create pvc first
+//   3) no prebind and create pv first
+// The case of prebinding and creating the pv first is not possible due to using a
+// *generated* name in the pvc, and thus not knowing the claim's name until after
+// it has been created.
+// **Note: this function complements makePersistentVolume() and fills in the remaining
+// name field in the pv's ClaimRef.
+func createPVandPVC(c *client.Client, serverIP, ns string, pvFirst, preBind bool) (*api.PersistentVolume, *api.PersistentVolumeClaim, error) {
+
+	var bindTo *api.PersistentVolumeClaim
+	var err error
+
+	pvc := makePersistentVolumeClaim(ns) // pvc.Name not known yet
+
+	bindTo = nil
+	if preBind { // implies pvc *must* be created before the pv
+		pvFirst = false
+		bindTo = pvc
+	}
+	pv := makePersistentVolume(serverIP, bindTo)
+
+	if pvFirst {
+		By("Creating the PV followed by the PVC")
+		pv, err = createPV(c, pv)
+	} else {
+		By("Creating the PVC followed by the PV")
+		pvc, err = createPVC(c, ns, pvc)
+	}
+	if err != nil {
+		return nil, nil, err
+	}
+
+	if pvFirst {
+		pvc, err = createPVC(c, ns, pvc)
+		if err != nil {
+			return pv, nil, err
+		}
+	} else {
+		// need to fill-in claimRef with pvc.Name
+		pv.Spec.ClaimRef.Name = pvc.Name
+		pv, err = createPV(c, pv)
+		if err != nil {
+			return nil, pvc, err
+		}
+	}
+
+	return pv, pvc, nil
+}
+
+// Wait for the pv and pvc to bind to each other. Fail test on errors.
+func waitOnPVandPVC(c *client.Client, ns string, pv *api.PersistentVolume, pvc *api.PersistentVolumeClaim) error {
+
+	// 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(api.ClaimBound, c, ns, pvc.Name, 3*time.Second, 300*time.Second)
+	if err != nil {
+		return fmt.Errorf("PersistentVolumeClaim failed to enter a bound state: %+v", err)
+	}
+
+	// Wait for PersistentVolume.Status.Phase to be Bound, which it should be
+	// since the PVC is already bound.
+	err = framework.WaitForPersistentVolumePhase(api.VolumeBound, c, pv.Name, 3*time.Second, 300*time.Second)
+	if err != nil {
+		return fmt.Errorf("PersistentVolume failed to enter a bound state even though PVC is Bound: %+v", err)
+	}
+
+	return nil
+}
+
+// Waits for the pv and pvc to be bound to each other, then checks that the pv's
+// claimRef matches the pvc. Fails test on errors.
+func waitAndValidatePVandPVC(c *client.Client, ns string, pv *api.PersistentVolume, pvc *api.PersistentVolumeClaim) (*api.PersistentVolume, *api.PersistentVolumeClaim, error) {
+
+	var err error
+
+	// Wait for pv and pvc to bind to each other
+	if err = waitOnPVandPVC(c, ns, pv, pvc); err != nil {
+		return pv, pvc, err
+	}
+
+	// Check that the PersistentVolume.ClaimRef is valid and matches the PVC
+	framework.Logf("Checking PersistentVolume ClaimRef is non-nil")
+	pv, err = c.PersistentVolumes().Get(pv.Name)
+	if err != nil {
+		return pv, pvc, fmt.Errorf("Cannot re-get PersistentVolume %v:", pv.Name)
+	}
+
+	pvc, err = c.PersistentVolumeClaims(ns).Get(pvc.Name)
+	if err != nil {
+		return pv, pvc, fmt.Errorf("Cannot re-get PersistentVolumeClaim %v:", pvc.Name)
+	}
+
+	if pv.Spec.ClaimRef == nil || pv.Spec.ClaimRef.UID != pvc.UID {
+		pvJSON, _ := json.Marshal(pv.Spec.ClaimRef)
+		return pv, pvc, fmt.Errorf("Expected Bound PersistentVolume %v to have valid ClaimRef: %+v", pv.Name, string(pvJSON))
+	}
+
+	return pv, pvc, nil
+}
+
+// Test the pod's exitcode to be zero.
+func testPodSuccessOrFail(f *framework.Framework, c *client.Client, ns string, pod *api.Pod) error {
+
+	By("Pod should terminate with exitcode 0 (success)")
+
+	err := framework.WaitForPodSuccessInNamespace(c, pod.Name, pod.Spec.Containers[0].Name, ns)
+	if err != nil {
+		return fmt.Errorf("Pod %v returned non-zero exitcode: %+v", pod.Name, err)
+	}
+
+	framework.Logf("pod %v exited successfully", pod.Name)
+	return nil
+}
+
+// Delete the passed in pod.
+func deletePod(f *framework.Framework, c *client.Client, ns string, pod *api.Pod) error {
+
+	framework.Logf("Deleting pod %v", pod.Name)
+	err := c.Pods(ns).Delete(pod.Name, nil)
+	if err != nil {
+		return fmt.Errorf("Pod %v encountered a delete error: %v", pod.Name, err)
+	}
+
+	// Wait for pod to terminate
+	err = f.WaitForPodTerminated(pod.Name, "")
+	if err != nil && !apierrs.IsNotFound(err) {
+		return fmt.Errorf("Pod %v will not teminate: %v", pod.Name, err)
+	}
+
+	// Re-get the pod to double check that it has been deleted; expect err
+	// Note: Get() writes a log error if the pod is not found
+	_, err = c.Pods(ns).Get(pod.Name)
+	if err == nil {
+		return fmt.Errorf("Pod %v has been deleted but able to re-Get the deleted pod", pod.Name)
+	}
+	if !apierrs.IsNotFound(err) {
+		return fmt.Errorf("Pod %v has been deleted but still exists: %v", pod.Name, err)
+	}
+
+	framework.Logf("Ignore \"not found\" error above. Pod %v successfully deleted", pod.Name)
+	return nil
+}
+
+// Create the test pod, wait for (hopefully) success, and then delete the pod.
+func createWaitAndDeletePod(f *framework.Framework, c *client.Client, ns string, claimName string) error {
+
+	var errmsg string
+
+	framework.Logf("Creating nfs test pod")
+
+	// Make pod spec
+	pod := makeWritePod(ns, claimName)
+
+	// Instantiate pod (Create)
+	runPod, err := c.Pods(ns).Create(pod)
+	if err != nil || runPod == nil {
+		name := ""
+		if runPod != nil {
+			name = runPod.Name
+		}
+		return fmt.Errorf("Create test pod %v failed: %v", name, err)
+	}
+
+	// Wait for the test pod to complete its lifecycle
+	podErr := testPodSuccessOrFail(f, c, ns, runPod)
+
+	// Regardless of podErr above, delete the pod if it exists
+	if runPod != nil {
+		err = deletePod(f, c, ns, runPod)
+	}
+
+	// Check results of pod success and pod delete
+	if podErr != nil {
+		errmsg = fmt.Sprintf("Pod %v exited with non-zero exitcode: %v", runPod.Name, podErr)
+	}
+	if err != nil { // Delete error
+		if len(errmsg) > 0 {
+			errmsg += "; and "
+		}
+		errmsg += fmt.Sprintf("Delete error on pod %v: %v", runPod.Name, err)
+	}
+
+	if len(errmsg) > 0 {
+		return fmt.Errorf(errmsg)
+	}
+
+	return nil
 }

 var _ = framework.KubeDescribe("PersistentVolumes", func() {
+
+	// global vars for the It() tests below
 	f := framework.NewDefaultFramework("pv")
 	var c *client.Client
 	var ns string
-	BeforeEach(func() {
-		c = f.Client
-		ns = f.Namespace.Name
-	})
+	var NFSconfig VolumeTestConfig
+	var serverIP string
+	var nfsServerPod *api.Pod
+	var pv *api.PersistentVolume
+	var pvc *api.PersistentVolumeClaim
+	var err error

-	It("should create a PersistentVolume, Claim, and a client Pod that will test the read/write access of the volume[Flaky]", func() {
-		config := VolumeTestConfig{
-			namespace:   ns,
+	// config for the nfs-server pod in the default namespace
+	NFSconfig = VolumeTestConfig{
+		namespace:   api.NamespaceDefault,
 		prefix:      "nfs",
 		serverImage: "gcr.io/google_containers/volume-nfs:0.6",
 		serverPorts: []int{2049},
 	}

-		defer func() {
-			persistentVolumeTestCleanup(c, config)
-		}()
+	BeforeEach(func() {
+		c = f.Client
+		ns = f.Namespace.Name

-		// Create the nfs server pod
-		pod := startVolumeServer(c, config)
-		serverIP := pod.Status.PodIP
+		// If it doesn't exist, create the nfs server pod in "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)
-
-		// Define the PersistentVolume and PersistentVolumeClaim
-		pv := makePersistentVolume(serverIP)
-		pvc := makePersistentVolumeClaim(ns)
-
-		// Create the PersistentVolume and wait for PersistentVolume.Status.Phase to be Available
-		// defer deletion to clean up the PV should the test fail post-creation.
-		framework.Logf("Creating PersistentVolume")
-		pv, err := c.PersistentVolumes().Create(pv)
-		if err != nil {
-			framework.Failf("Create PersistentVolume failed: %v", err)
-		}
-		defer deletePersistentVolume(c, pv)
-		framework.WaitForPersistentVolumePhase(api.VolumeAvailable, c, pv.Name, 1*time.Second, 20*time.Second)
-
-		// Create the PersistentVolumeClaim and wait for Bound phase
-		framework.Logf("Creating PersistentVolumeClaim")
-		pvc, err = c.PersistentVolumeClaims(ns).Create(pvc)
-		if err != nil {
-			framework.Failf("Create PersistentVolumeClaim failed: %v", err)
-		}
-		framework.WaitForPersistentVolumeClaimPhase(api.ClaimBound, c, ns, pvc.Name, 3*time.Second, 300*time.Second)
-
-		// Wait for PersistentVolume.Status.Phase to be Bound. Can take several minutes.
-		err = framework.WaitForPersistentVolumePhase(api.VolumeBound, c, pv.Name, 3*time.Second, 300*time.Second)
-		if err != nil {
-			framework.Failf("PersistentVolume failed to enter a bound state: %+v", err)
-		}
-		// Check the PersistentVolume.ClaimRef.UID for non-nil value as confirmation of the bound state.
-		framework.Logf("Checking PersistentVolume ClaimRef is non-nil")
-		pv, err = c.PersistentVolumes().Get(pv.Name)
-		if pv.Spec.ClaimRef == nil || len(pv.Spec.ClaimRef.UID) == 0 {
-			pvJson, _ := json.MarshalIndent(pv, "", "  ")
-			framework.Failf("Expected PersistentVolume to be bound, but got nil ClaimRef or UID: %+v", string(pvJson))
-		}
-
-		// Check the PersistentVolumeClaim.Status.Phase for Bound state
-		framework.Logf("Checking PersistentVolumeClaim status is Bound")
-		pvc, err = c.PersistentVolumeClaims(ns).Get(pvc.Name)
-		if pvcPhase := pvc.Status.Phase; pvcPhase != "Bound" {
-			framework.Failf("Expected PersistentVolumeClaim status Bound. Actual:  %+v.  Error: %+v", pvcPhase, err)
-		}
-
-		// Check that the PersistentVolume's ClaimRef contains the UID of the PersistendVolumeClaim
-		if pvc.ObjectMeta.UID != pv.Spec.ClaimRef.UID {
-			framework.Failf("Binding failed: PersistentVolumeClaim UID does not match PersistentVolume's ClaimRef UID. ")
-		}
-
-		// writePod writes to the nfs volume
-		framework.Logf("Creating writePod")
-		pvc, _ = c.PersistentVolumeClaims(ns).Get(pvc.Name)
-		writePod := makeWritePod(ns, pvc.Name)
-		writePod, err = c.Pods(ns).Create(writePod)
-		if err != nil {
-			framework.Failf("Create writePod failed: %+v", err)
-		}
-
-		// Wait for the writePod to complete it's lifecycle
-		err = framework.WaitForPodSuccessInNamespace(c, writePod.Name, writePod.Spec.Containers[0].Name, writePod.Namespace)
-		if err != nil {
-			framework.Failf("WritePod exited with error: %+v", err)
-		} else {
-			framework.Logf("WritePod exited without error.")
 		}
+	})

+	AfterEach(func() {
+		if c != nil && len(ns) > 0 { // still have client and namespace
+			if pvc != nil && len(pvc.Name) > 0 {
 				// Delete the PersistentVolumeClaim
-		framework.Logf("Deleting PersistentVolumeClaim to trigger PV Recycling")
-		err = c.PersistentVolumeClaims(ns).Delete(pvc.Name)
+				framework.Logf("AfterEach: PVC %v is non-nil, deleting claim", pvc.Name)
+				err := c.PersistentVolumeClaims(ns).Delete(pvc.Name)
+				if err != nil && !apierrs.IsNotFound(err) {
+					framework.Logf("AfterEach: delete of PersistentVolumeClaim %v error: %v", pvc.Name, err)
+				}
+				pvc = nil
+			}
+			if pv != nil && len(pv.Name) > 0 {
+				framework.Logf("AfterEach: PV %v is non-nil, deleting pv", pv.Name)
+				err := c.PersistentVolumes().Delete(pv.Name)
+				if err != nil && !apierrs.IsNotFound(err) {
+					framework.Logf("AfterEach: delete of PersistentVolume %v error: %v", pv.Name, err)
+				}
+				pv = nil
+			}
+		}
+	})
+
+	// Execute after *all* the tests have run
+	AddCleanupAction(func() {
+		if nfsServerPod != nil && c != nil {
+			framework.Logf("AfterSuite: nfs-server pod %v is non-nil, deleting pod", nfsServerPod.Name)
+			nfsServerPodCleanup(c, NFSconfig)
+			nfsServerPod = nil
+		}
+	})
+
+	// Individual tests follow:
+	//
+	// Create an nfs PV, a claim that matches the PV, 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 PersistentVolume, Claim, and Pod that will test write access of the volume [Flaky]", func() {
+
+		pv, pvc, err = createPVandPVC(c, serverIP, ns, true /*pv first*/, false)
 		if err != nil {
-			framework.Failf("Delete PersistentVolumeClaim failed: %v", err)
+			framework.Failf("%v", err)
 		}

-		// Wait for the PersistentVolume phase to return to Available
-		framework.Logf("Waiting for recycling process to complete.")
-		err = framework.WaitForPersistentVolumePhase(api.VolumeAvailable, c, pv.Name, 3*time.Second, 300*time.Second)
+		pv, pvc, err = waitAndValidatePVandPVC(c, ns, pv, pvc)
 		if err != nil {
-			framework.Failf("Recycling failed: %v", err)
+			framework.Failf("%v", err)
 		}

-		// Examine the PersistentVolume.ClaimRef and UID.  Expect nil values.
-		pv, err = c.PersistentVolumes().Get(pv.Name)
-		if pv.Spec.ClaimRef != nil && len(pv.Spec.ClaimRef.UID) > 0 {
-			crjson, _ := json.MarshalIndent(pv.Spec.ClaimRef, "", "  ")
-			framework.Failf("Expected a nil ClaimRef or UID. Found: ", string(crjson))
+		By("Checking pod has write access to PersistentVolume")
+
+		if err = createWaitAndDeletePod(f, c, ns, pvc.Name); err != nil {
+			framework.Failf("%v", err)
 		}

+		// Delete the PVC before deleting PV, wait for PV to be Available
+		pv, pvc, err = deletePVCandValidatePV(c, ns, pvc, pv)
+		if err != nil {
+			framework.Failf("%v", err)
+		}
+
+		// Last cleanup step is to delete the pv
+		pv, err = deletePersistentVolume(c, pv)
+		if err != nil {
+			framework.Failf("%v", err)
+		}
+	})
+
+	// Create an nfs PV that is *pre-bound* to a claim. Create 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 pre-bound PersistentVolume, Claim, and Pod that will test write access of the volume [Flaky]", func() {
+
+		pv, pvc, err = createPVandPVC(c, serverIP, ns, false /*pvc first*/, true /*prebind*/)
+		if err != nil {
+			framework.Failf("%v", err)
+		}
+
+		pv, pvc, err = waitAndValidatePVandPVC(c, ns, pv, pvc)
+		if err != nil {
+			framework.Failf("%v", err)
+		}
+
+		// checkPod writes to the nfs volume
+		By("Checking pod has write access to pre-bound PersistentVolume")
+		// Instantiate pod, wait for it to exit, then delete it
+		if err = createWaitAndDeletePod(f, c, ns, pvc.Name); err != nil {
+			framework.Failf("%v", err)
+		}
+
+		// Delete the PVC before deleting PV, wait for PV to be Available
+		pv, pvc, err = deletePVCandValidatePV(c, ns, pvc, pv)
+		if err != nil {
+			framework.Failf("%v", err)
+		}
+
+		// Last cleanup step is to delete the pv
+		pv, err = deletePersistentVolume(c, pv)
+		if err != nil {
+			framework.Failf("%v", err)
+		}
 	})
 })

-func makePersistentVolume(serverIP string) *api.PersistentVolume {
-	// Takes an NFS server IP address and returns a PersistentVolume object for instantiation.
+// 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 createPVandPVC().
+func makePersistentVolume(serverIP string, pvc *api.PersistentVolumeClaim) *api.PersistentVolume {
 	// Specs are expected to match this test's PersistentVolumeClaim
+
+	var claimRef *api.ObjectReference
+
+	claimRef = nil
+	if pvc != nil {
+		claimRef = &api.ObjectReference{
+			Name:      pvc.Name,
+			Namespace: pvc.Namespace,
+		}
+	}
+
 	return &api.PersistentVolume{
 		ObjectMeta: api.ObjectMeta{
 			GenerateName: "nfs-",
@@ -192,13 +504,15 @@ func makePersistentVolume(serverIP string) *api.PersistentVolume {
 				api.ReadOnlyMany,
 				api.ReadWriteMany,
 			},
+			ClaimRef: claimRef,
 		},
 	}
 }

+// Returns a PVC definition based on the namespace.
 func makePersistentVolumeClaim(ns string) *api.PersistentVolumeClaim {
-	// Takes a namespace and returns a PersistentVolumeClaim object for instantiation.
 	// Specs are expected to match this test's PersistentVolume
+
 	return &api.PersistentVolumeClaim{
 		ObjectMeta: api.ObjectMeta{
 			GenerateName: "pvc-",
@@ -219,6 +533,8 @@ func makePersistentVolumeClaim(ns string) *api.PersistentVolumeClaim {
 	}
 }

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