Added local storage e2e test for VolumeMode: block

VolumeMode block requires alpha feature-gate BlockVolume=true

Added VolumeMode to e2e test framework for pv and pvc
Added volumeDevices to e2e test framework for block volumes

pkg/volume/util/util_linux.go

@@ -61,7 +61,7 @@ func (v VolumePathHandler) GetLoopDevice(path string) (string, error) {
 	cmd := exec.Command(losetupPath, args...)
 	out, err := cmd.CombinedOutput()
 	if err != nil {
-		glog.V(2).Infof("Failed device discover command for path %s: %v", path, err)
+		glog.V(2).Infof("Failed device discover command for path %s: %v %s", path, err, out)
 		return "", err
 	}
 	return parseLosetupOutputForDevice(out)
@@ -72,7 +72,7 @@ func makeLoopDevice(path string) (string, error) {
 	cmd := exec.Command(losetupPath, args...)
 	out, err := cmd.CombinedOutput()
 	if err != nil {
-		glog.V(2).Infof("Failed device create command for path %s: %v", path, err)
+		glog.V(2).Infof("Failed device create command for path: %s %v %s ", path, err, out)
 		return "", err
 	}
 	return parseLosetupOutputForDevice(out)

test/e2e/framework/pv_util.go

@@ -81,6 +81,7 @@ type PersistentVolumeConfig struct {
 	Labels           labels.Set
 	StorageClassName string
 	NodeAffinity     *v1.VolumeNodeAffinity
+	VolumeMode       *v1.PersistentVolumeMode
 }
 
 // PersistentVolumeClaimConfig is consumed by MakePersistentVolumeClaim() to generate a PVC object.
@@ -92,6 +93,7 @@ type PersistentVolumeClaimConfig struct {
 	Annotations      map[string]string
 	Selector         *metav1.LabelSelector
 	StorageClassName *string
+	VolumeMode       *v1.PersistentVolumeMode
 }
 
 // Clean up a pv and pvc in a single pv/pvc test case.
@@ -581,7 +583,7 @@ func MakePersistentVolume(pvConfig PersistentVolumeConfig) *v1.PersistentVolume
 			Namespace: pvConfig.Prebind.Namespace,
 		}
 	}
-	pv := &v1.PersistentVolume{
+	return &v1.PersistentVolume{
 		ObjectMeta: metav1.ObjectMeta{
 			GenerateName: pvConfig.NamePrefix,
 			Labels:       pvConfig.Labels,
@@ -603,9 +605,9 @@ func MakePersistentVolume(pvConfig PersistentVolumeConfig) *v1.PersistentVolume
 			ClaimRef:         claimRef,
 			StorageClassName: pvConfig.StorageClassName,
 			NodeAffinity:     pvConfig.NodeAffinity,
+			VolumeMode:       pvConfig.VolumeMode,
 		},
 	}
-	return pv
 }
 
 // Returns a PVC definition based on the namespace.
@@ -635,6 +637,7 @@ func MakePersistentVolumeClaim(cfg PersistentVolumeClaimConfig, ns string) *v1.P
 				},
 			},
 			StorageClassName: cfg.StorageClassName,
+			VolumeMode:       cfg.VolumeMode,
 		},
 	}
 }
@@ -868,14 +871,21 @@ func MakeSecPod(ns string, pvclaims []*v1.PersistentVolumeClaim, isPrivileged bo
 			RestartPolicy: v1.RestartPolicyOnFailure,
 		},
 	}
-	var volumeMounts = make([]v1.VolumeMount, len(pvclaims))
+	var volumeMounts = make([]v1.VolumeMount, 0)
+	var volumeDevices = make([]v1.VolumeDevice, 0)
 	var volumes = make([]v1.Volume, len(pvclaims))
 	for index, pvclaim := range pvclaims {
 		volumename := fmt.Sprintf("volume%v", index+1)
-		volumeMounts[index] = v1.VolumeMount{Name: volumename, MountPath: "/mnt/" + volumename}
+		if pvclaim.Spec.VolumeMode != nil && *pvclaim.Spec.VolumeMode == v1.PersistentVolumeBlock {
+			volumeDevices = append(volumeDevices, v1.VolumeDevice{Name: volumename, DevicePath: "/mnt/" + volumename})
+		} else {
+			volumeMounts = append(volumeMounts, v1.VolumeMount{Name: volumename, MountPath: "/mnt/" + volumename})
+		}
+
 		volumes[index] = v1.Volume{Name: volumename, VolumeSource: v1.VolumeSource{PersistentVolumeClaim: &v1.PersistentVolumeClaimVolumeSource{ClaimName: pvclaim.Name, ReadOnly: false}}}
 	}
 	podSpec.Spec.Containers[0].VolumeMounts = volumeMounts
+	podSpec.Spec.Containers[0].VolumeDevices = volumeDevices
 	podSpec.Spec.Volumes = volumes
 	podSpec.Spec.SecurityContext.SELinuxOptions = seLinuxLabel
 	return podSpec

test/e2e/storage/persistent_volumes-local.go

@@ -67,18 +67,22 @@ const (
 	TmpfsLocalVolumeType localVolumeType = "tmpfs"
 	// tests based on local ssd at /mnt/disks/by-uuid/
 	GCELocalSSDVolumeType localVolumeType = "gce-localssd-scsi-fs"
+	// Creates a local file, formats it, and maps it as a block device.
+	BlockLocalVolumeType localVolumeType = "block"
 )
 
 var setupLocalVolumeMap = map[localVolumeType]func(*localTestConfig, *v1.Node) *localTestVolume{
 	GCELocalSSDVolumeType:    setupLocalVolumeGCELocalSSD,
 	TmpfsLocalVolumeType:     setupLocalVolumeTmpfs,
 	DirectoryLocalVolumeType: setupLocalVolumeDirectory,
+	BlockLocalVolumeType:     setupLocalVolumeBlock,
 }
 
 var cleanupLocalVolumeMap = map[localVolumeType]func(*localTestConfig, *localTestVolume){
 	GCELocalSSDVolumeType:    cleanupLocalVolumeGCELocalSSD,
 	TmpfsLocalVolumeType:     cleanupLocalVolumeTmpfs,
 	DirectoryLocalVolumeType: cleanupLocalVolumeDirectory,
+	BlockLocalVolumeType:     cleanupLocalVolumeBlock,
 }
 
 type localTestVolume struct {
@@ -92,6 +96,9 @@ type localTestVolume struct {
 	pv *v1.PersistentVolume
 	// Type of local volume
 	localVolumeType localVolumeType
+	// Path to the loop block device on the host node.
+	// Used during cleanup after block tests.
+	loopDevDir string
 }
 
 const (
@@ -168,7 +175,7 @@ var _ = utils.SIGDescribe("PersistentVolumes-local ", func() {
 		}
 	})
 
-	localVolumeTypes := []localVolumeType{DirectoryLocalVolumeType, TmpfsLocalVolumeType, GCELocalSSDVolumeType}
+	localVolumeTypes := []localVolumeType{DirectoryLocalVolumeType, TmpfsLocalVolumeType, GCELocalSSDVolumeType, BlockLocalVolumeType}
 	for _, tempTestVolType := range localVolumeTypes {
 
 		// New variable required for gingko test closures
@@ -177,7 +184,11 @@ var _ = utils.SIGDescribe("PersistentVolumes-local ", func() {
 		if testVolType == GCELocalSSDVolumeType {
 			serialStr = " [Serial]"
 		}
-		ctxString := fmt.Sprintf("[Volume type: %s]%v", testVolType, serialStr)
+		alphaStr := ""
+		if testVolType == BlockLocalVolumeType {
+			alphaStr = " [Feature:BlockVolume]"
+		}
+		ctxString := fmt.Sprintf("[Volume type: %s]%v%v", testVolType, serialStr, alphaStr)
 		testMode := immediateMode
 
 		Context(ctxString, func() {
@@ -218,15 +229,15 @@ var _ = utils.SIGDescribe("PersistentVolumes-local ", func() {
 				It("should be able to mount volume and read from pod1", func() {
 					By("Reading in pod1")
 					// testFileContent was written during setupLocalVolume
-					testReadFileContent(volumeDir, testFile, testFileContent, pod1)
+					testReadFileContent(volumeDir, testFile, testFileContent, pod1, testVolType)
 				})
 
 				It("should be able to mount volume and write from pod1", func() {
 					// testFileContent was written during setupLocalVolume
-					testReadFileContent(volumeDir, testFile, testFileContent, pod1)
+					testReadFileContent(volumeDir, testFile, testFileContent, pod1, testVolType)
 
 					By("Writing in pod1")
-					writeCmd, _ := createWriteAndReadCmds(volumeDir, testFile, testVol.hostDir /*writeTestFileContent*/)
+					writeCmd, _ := createWriteAndReadCmds(volumeDir, testFile, testVol.hostDir /*writeTestFileContent*/, testVolType)
 					podRWCmdExec(pod1, writeCmd)
 				})
 			})
@@ -365,7 +376,7 @@ var _ = utils.SIGDescribe("PersistentVolumes-local ", func() {
 
 			// Delete the persistent volume claim: file will be cleaned up and volume be re-created.
 			By("Deleting the persistent volume claim to clean up persistent volume and re-create one")
-			writeCmd, _ := createWriteAndReadCmds(volumePath, testFile, testFileContent)
+			writeCmd, _ := createWriteAndReadCmds(volumePath, testFile, testFileContent, DirectoryLocalVolumeType)
 			err = framework.IssueSSHCommand(writeCmd, framework.TestContext.Provider, config.node0)
 			Expect(err).NotTo(HaveOccurred())
 			err = config.client.CoreV1().PersistentVolumeClaims(claim.Namespace).Delete(claim.Name, &metav1.DeleteOptions{})
@@ -495,7 +506,7 @@ var _ = utils.SIGDescribe("PersistentVolumes-local ", func() {
 				for i := 0; i < numConcurrentPods; i++ {
 					pvcs := []*v1.PersistentVolumeClaim{}
 					for j := 0; j < volsPerPod; j++ {
-						pvc := framework.MakePersistentVolumeClaim(makeLocalPVCConfig(config), config.ns)
+						pvc := framework.MakePersistentVolumeClaim(makeLocalPVCConfig(config, DirectoryLocalVolumeType), config.ns)
 						pvc, err := framework.CreatePVC(config.client, config.ns, pvc)
 						framework.ExpectNoError(err)
 						pvcs = append(pvcs, pvc)
@@ -621,7 +632,7 @@ func twoPodsReadWriteTest(config *localTestConfig, testVol *localTestVolume) {
 	verifyLocalPod(config, testVol, pod1, config.node0.Name)
 
 	// testFileContent was written during setupLocalVolume
-	testReadFileContent(volumeDir, testFile, testFileContent, pod1)
+	testReadFileContent(volumeDir, testFile, testFileContent, pod1, testVol.localVolumeType)
 
 	By("Creating pod2 to read from the PV")
 	pod2, pod2Err := createLocalPod(config, testVol)
@@ -629,15 +640,15 @@ func twoPodsReadWriteTest(config *localTestConfig, testVol *localTestVolume) {
 	verifyLocalPod(config, testVol, pod2, config.node0.Name)
 
 	// testFileContent was written during setupLocalVolume
-	testReadFileContent(volumeDir, testFile, testFileContent, pod2)
+	testReadFileContent(volumeDir, testFile, testFileContent, pod2, testVol.localVolumeType)
 
-	writeCmd := createWriteCmd(volumeDir, testFile, testVol.hostDir /*writeTestFileContent*/)
+	writeCmd := createWriteCmd(volumeDir, testFile, testVol.hostDir /*writeTestFileContent*/, testVol.localVolumeType)
 
 	By("Writing in pod1")
 	podRWCmdExec(pod1, writeCmd)
 
 	By("Reading in pod2")
-	testReadFileContent(volumeDir, testFile, testVol.hostDir, pod2)
+	testReadFileContent(volumeDir, testFile, testVol.hostDir, pod2, testVol.localVolumeType)
 
 	By("Deleting pod1")
 	framework.DeletePodOrFail(config.client, config.ns, pod1.Name)
@@ -653,9 +664,9 @@ func twoPodsReadWriteSerialTest(config *localTestConfig, testVol *localTestVolum
 	verifyLocalPod(config, testVol, pod1, config.node0.Name)
 
 	// testFileContent was written during setupLocalVolume
-	testReadFileContent(volumeDir, testFile, testFileContent, pod1)
+	testReadFileContent(volumeDir, testFile, testFileContent, pod1, testVol.localVolumeType)
 
-	writeCmd := createWriteCmd(volumeDir, testFile, testVol.hostDir /*writeTestFileContent*/)
+	writeCmd := createWriteCmd(volumeDir, testFile, testVol.hostDir /*writeTestFileContent*/, testVol.localVolumeType)
 
 	By("Writing in pod1")
 	podRWCmdExec(pod1, writeCmd)
@@ -669,7 +680,7 @@ func twoPodsReadWriteSerialTest(config *localTestConfig, testVol *localTestVolum
 	verifyLocalPod(config, testVol, pod2, config.node0.Name)
 
 	By("Reading in pod2")
-	testReadFileContent(volumeDir, testFile, testVol.hostDir, pod2)
+	testReadFileContent(volumeDir, testFile, testVol.hostDir, pod2, testVol.localVolumeType)
 
 	By("Deleting pod2")
 	framework.DeletePodOrFail(config.client, config.ns, pod2.Name)
@@ -731,8 +742,8 @@ func cleanupLocalVolumes(config *localTestConfig, volumes []*localTestVolume) {
 }
 
 func setupWriteTestFile(hostDir string, config *localTestConfig, localVolumeType localVolumeType, node *v1.Node) *localTestVolume {
-	writeCmd, _ := createWriteAndReadCmds(hostDir, testFile, testFileContent)
+	writeCmd, _ := createWriteAndReadCmds(hostDir, testFile, testFileContent, localVolumeType)
-	By(fmt.Sprintf("Creating local volume on node %q at path %q", node.Name, hostDir))
+	By(fmt.Sprintf("Creating test file on node %q in path %q", node.Name, hostDir))
 	err := framework.IssueSSHCommand(writeCmd, framework.TestContext.Provider, node)
 	Expect(err).NotTo(HaveOccurred())
 	return &localTestVolume{
@@ -755,17 +766,37 @@ func setupLocalVolumeGCELocalSSD(config *localTestConfig, node *v1.Node) *localT
 	Expect(err).NotTo(HaveOccurred())
 	dirName := strings.Fields(res.Stdout)[0]
 	hostDir := "/mnt/disks/by-uuid/google-local-ssds-scsi-fs/" + dirName
-	// populate volume with testFile containing testFileContent
+	// Populate volume with testFile containing testFileContent.
 	return setupWriteTestFile(hostDir, config, GCELocalSSDVolumeType, node)
 }
 
 func setupLocalVolumeDirectory(config *localTestConfig, node *v1.Node) *localTestVolume {
 	testDirName := "local-volume-test-" + string(uuid.NewUUID())
 	hostDir := filepath.Join(hostBase, testDirName)
-	// populate volume with testFile containing testFileContent
+	// Populate volume with testFile containing testFileContent.
 	return setupWriteTestFile(hostDir, config, DirectoryLocalVolumeType, node)
 }
 
+func setupLocalVolumeBlock(config *localTestConfig, node *v1.Node) *localTestVolume {
+	testDirName := "local-volume-test-" + string(uuid.NewUUID())
+	hostDir := filepath.Join(hostBase, testDirName)
+	createAndMapBlockLocalVolume(config, hostDir, node)
+	loopDev := getBlockLoopDev(hostDir, node)
+	// Populate block volume with testFile containing testFileContent.
+	volume := setupWriteTestFile(loopDev, config, BlockLocalVolumeType, node)
+	volume.hostDir = loopDev
+	volume.loopDevDir = hostDir
+	return volume
+}
+
+// Determine the /dev/loopXXX device associated with this test, via its hostDir.
+func getBlockLoopDev(hostDir string, node *v1.Node) string {
+	loopDevCmd := fmt.Sprintf("E2E_LOOP_DEV=$(sudo losetup | grep %s/file | awk '{ print $1 }') 2>&1 > /dev/null && echo ${E2E_LOOP_DEV}", hostDir)
+	loopDevResult, err := framework.IssueSSHCommandWithResult(loopDevCmd, framework.TestContext.Provider, node)
+	Expect(err).NotTo(HaveOccurred())
+	return strings.TrimSpace(loopDevResult.Stdout)
+}
+
 func verifyLocalVolume(config *localTestConfig, volume *localTestVolume) {
 	framework.ExpectNoError(framework.WaitOnPVandPVC(config.client, config.ns, volume.pv, volume.pvc))
 }
@@ -777,7 +808,7 @@ func verifyLocalPod(config *localTestConfig, volume *localTestVolume, pod *v1.Po
 	Expect(podNodeName).To(Equal(expectedNodeName))
 }
 
-// Deletes the PVC/PV, and launches a pod with hostpath volume to remove the test directory
+// Deletes the PVC/PV, and launches a pod with hostpath volume to remove the test directory.
 func cleanupLocalVolumeGCELocalSSD(config *localTestConfig, volume *localTestVolume) {
 	By("Removing the test directory")
 	removeCmd := fmt.Sprintf("rm %s", volume.hostDir+"/"+testFile)
@@ -785,7 +816,7 @@ func cleanupLocalVolumeGCELocalSSD(config *localTestConfig, volume *localTestVol
 	Expect(err).NotTo(HaveOccurred())
 }
 
-// Deletes the PVC/PV, and launches a pod with hostpath volume to remove the test directory
+// Deletes the PVC/PV, and launches a pod with hostpath volume to remove the test directory.
 func cleanupLocalVolumeTmpfs(config *localTestConfig, volume *localTestVolume) {
 	unmountTmpfsLocalVolume(config, volume.hostDir, volume.node)
 
@@ -795,7 +826,7 @@ func cleanupLocalVolumeTmpfs(config *localTestConfig, volume *localTestVolume) {
 	Expect(err).NotTo(HaveOccurred())
 }
 
-// Deletes the PVC/PV, and launches a pod with hostpath volume to remove the test directory
+// Deletes the PVC/PV, and launches a pod with hostpath volume to remove the test directory.
 func cleanupLocalVolumeDirectory(config *localTestConfig, volume *localTestVolume) {
 	By("Removing the test directory")
 	removeCmd := fmt.Sprintf("rm -r %s", volume.hostDir)
@@ -803,11 +834,26 @@ func cleanupLocalVolumeDirectory(config *localTestConfig, volume *localTestVolum
 	Expect(err).NotTo(HaveOccurred())
 }
 
-func makeLocalPVCConfig(config *localTestConfig) framework.PersistentVolumeClaimConfig {
+// Deletes the PVC/PV and removes the test directory holding the block file.
-	return framework.PersistentVolumeClaimConfig{
+func cleanupLocalVolumeBlock(config *localTestConfig, volume *localTestVolume) {
+	volume.hostDir = volume.loopDevDir
+	unmapBlockLocalVolume(config, volume.hostDir, volume.node)
+	By("Removing the test directory")
+	removeCmd := fmt.Sprintf("rm -r %s", volume.hostDir)
+	err := framework.IssueSSHCommand(removeCmd, framework.TestContext.Provider, volume.node)
+	Expect(err).NotTo(HaveOccurred())
+}
+
+func makeLocalPVCConfig(config *localTestConfig, volumeType localVolumeType) framework.PersistentVolumeClaimConfig {
+	pvcConfig := framework.PersistentVolumeClaimConfig{
 		AccessModes:      []v1.PersistentVolumeAccessMode{v1.ReadWriteOnce},
 		StorageClassName: &config.scName,
 	}
+	if volumeType == BlockLocalVolumeType {
+		pvcVolumeMode := v1.PersistentVolumeBlock
+		pvcConfig.VolumeMode = &pvcVolumeMode
+	}
+	return pvcConfig
 }
 
 func makeLocalPVConfig(config *localTestConfig, volume *localTestVolume) framework.PersistentVolumeConfig {
@@ -821,7 +867,7 @@ func makeLocalPVConfig(config *localTestConfig, volume *localTestVolume) framewo
 		framework.Failf("Node does not have required label %q", nodeKey)
 	}
 
-	return framework.PersistentVolumeConfig{
+	pvConfig := framework.PersistentVolumeConfig{
 		PVSource: v1.PersistentVolumeSource{
 			Local: &v1.LocalVolumeSource{
 				Path: volume.hostDir,
@@ -845,6 +891,12 @@ func makeLocalPVConfig(config *localTestConfig, volume *localTestVolume) framewo
 			},
 		},
 	}
+
+	if volume.localVolumeType == BlockLocalVolumeType {
+		pvVolumeMode := v1.PersistentVolumeBlock
+		pvConfig.VolumeMode = &pvVolumeMode
+	}
+	return pvConfig
 }
 
 // Creates a PVC and PV with prebinding
@@ -852,8 +904,9 @@ func createLocalPVCsPVs(config *localTestConfig, volumes []*localTestVolume, mod
 	var err error
 
 	for _, volume := range volumes {
-		pvcConfig := makeLocalPVCConfig(config)
+		pvcConfig := makeLocalPVCConfig(config, volume.localVolumeType)
 		pvConfig := makeLocalPVConfig(config, volume)
+
 		volume.pv, volume.pvc, err = framework.CreatePVPVC(config.client, pvConfig, pvcConfig, config.ns, false)
 		framework.ExpectNoError(err)
 	}
@@ -878,7 +931,15 @@ func createLocalPVCsPVs(config *localTestConfig, volumes []*localTestVolume, mod
 }
 
 func makeLocalPod(config *localTestConfig, volume *localTestVolume, cmd string) *v1.Pod {
-	return framework.MakeSecPod(config.ns, []*v1.PersistentVolumeClaim{volume.pvc}, false, cmd, false, false, selinuxLabel)
+	pod := framework.MakeSecPod(config.ns, []*v1.PersistentVolumeClaim{volume.pvc}, false, cmd, false, false, selinuxLabel)
+	if pod == nil {
+		return pod
+	}
+	if volume.localVolumeType == BlockLocalVolumeType {
+		// Block e2e tests require utilities for writing to block devices (e.g. dd), and nginx has this utilites.
+		pod.Spec.Containers[0].Image = imageutils.GetE2EImage(imageutils.NginxSlim)
+	}
+	return pod
 }
 
 func makeLocalPodWithNodeAffinity(config *localTestConfig, volume *localTestVolume, nodeName string) (pod *v1.Pod) {
@@ -955,26 +1016,67 @@ func unmountTmpfsLocalVolume(config *localTestConfig, dir string, node *v1.Node)
 	Expect(err).NotTo(HaveOccurred())
 }
 
+func createAndMapBlockLocalVolume(config *localTestConfig, dir string, node *v1.Node) {
+	By(fmt.Sprintf("Creating block device on node %q using path %q", node.Name, dir))
+	mkdirCmd := fmt.Sprintf("mkdir -p %s", dir)
+	// Create 10MB file that will serve as the backing for block device.
+	ddCmd := fmt.Sprintf("dd if=/dev/zero of=%s/file bs=512 count=20480", dir)
+	losetupLoopDevCmd := fmt.Sprintf("E2E_LOOP_DEV=$(sudo losetup -f) && echo ${E2E_LOOP_DEV}")
+	losetupCmd := fmt.Sprintf("sudo losetup ${E2E_LOOP_DEV} %s/file", dir)
+	err := framework.IssueSSHCommand(fmt.Sprintf("%s && %s && %s && %s", mkdirCmd, ddCmd, losetupLoopDevCmd, losetupCmd), framework.TestContext.Provider, node)
+	Expect(err).NotTo(HaveOccurred())
+}
+
+func unmapBlockLocalVolume(config *localTestConfig, dir string, node *v1.Node) {
+	loopDev := getBlockLoopDev(dir, node)
+	By(fmt.Sprintf("Unmap block device %q on node %q at path %s/file", loopDev, node.Name, dir))
+	losetupDeleteCmd := fmt.Sprintf("sudo losetup -d %s", loopDev)
+	err := framework.IssueSSHCommand(losetupDeleteCmd, framework.TestContext.Provider, node)
+	Expect(err).NotTo(HaveOccurred())
+}
+
 // Create corresponding write and read commands
 // to be executed via SSH on the node with the local PV
-func createWriteAndReadCmds(testFileDir string, testFile string, writeTestFileContent string) (writeCmd string, readCmd string) {
+func createWriteAndReadCmds(testFileDir string, testFile string, writeTestFileContent string, volumeType localVolumeType) (writeCmd string, readCmd string) {
-	writeCmd = createWriteCmd(testFileDir, testFile, writeTestFileContent)
+	writeCmd = createWriteCmd(testFileDir, testFile, writeTestFileContent, volumeType)
-	readCmd = createReadCmd(testFileDir, testFile)
+	readCmd = createReadCmd(testFileDir, testFile, volumeType)
 	return writeCmd, readCmd
 }
 
-func createWriteCmd(testFileDir string, testFile string, writeTestFileContent string) string {
+func createWriteCmd(testDir string, testFile string, writeTestFileContent string, volumeType localVolumeType) string {
+	if volumeType == BlockLocalVolumeType {
+		// testDir is the block device.
+		testFileDir := filepath.Join("/tmp", testDir)
 		testFilePath := filepath.Join(testFileDir, testFile)
-	return fmt.Sprintf("mkdir -p %s; echo %s > %s", testFileDir, writeTestFileContent, testFilePath)
+		// Create a file containing the testFileContent.
+		writeTestFileCmd := fmt.Sprintf("mkdir -p %s; echo %s > %s", testFileDir, writeTestFileContent, testFilePath)
+		// sudo is needed when using ssh exec to node.
+		// sudo is not needed and does not exist in some containers (e.g. busybox), when using pod exec.
+		sudoCmd := fmt.Sprintf("SUDO_CMD=$(which sudo); echo ${SUDO_CMD}")
+		// Write the testFileContent into the block device.
+		writeBlockCmd := fmt.Sprintf("${SUDO_CMD} dd if=%s of=%s bs=512 count=100", testFilePath, testDir)
+		// Cleanup the file containing testFileContent.
+		deleteTestFileCmd := fmt.Sprintf("rm %s", testFilePath)
+		return fmt.Sprintf("%s && %s && %s && %s", writeTestFileCmd, sudoCmd, writeBlockCmd, deleteTestFileCmd)
+	} else {
+		testFilePath := filepath.Join(testDir, testFile)
+		return fmt.Sprintf("mkdir -p %s; echo %s > %s", testDir, writeTestFileContent, testFilePath)
 	}
-func createReadCmd(testFileDir string, testFile string) string {
+}
+func createReadCmd(testFileDir string, testFile string, volumeType localVolumeType) string {
+	if volumeType == BlockLocalVolumeType {
+		// Create the command to read the beginning of the block device and print it in ascii.
+		return fmt.Sprintf("hexdump -n 100 -e '100 \"%%_p\"' %s | head -1", testFileDir)
+	} else {
+		// Create the command to read (aka cat) a file.
 		testFilePath := filepath.Join(testFileDir, testFile)
 		return fmt.Sprintf("cat %s", testFilePath)
 	}
+}
 
 // Read testFile and evaluate whether it contains the testFileContent
-func testReadFileContent(testFileDir string, testFile string, testFileContent string, pod *v1.Pod) {
+func testReadFileContent(testFileDir string, testFile string, testFileContent string, pod *v1.Pod, volumeType localVolumeType) {
-	readCmd := createReadCmd(volumeDir, testFile)
+	readCmd := createReadCmd(volumeDir, testFile, volumeType)
 	readOut := podRWCmdExec(pod, readCmd)
 	Expect(readOut).To(ContainSubstring(testFileContent))
 }
@@ -990,6 +1092,7 @@ func createFileDoesntExistCmd(testFileDir string, testFile string) string {
 // Fail on error
 func podRWCmdExec(pod *v1.Pod, cmd string) string {
 	out, err := utils.PodExec(pod, cmd)
+	framework.Logf("podRWCmdExec out: %q err: %q", out, err)
 	Expect(err).NotTo(HaveOccurred())
 	return out
 }