test: support storage tests with non-standard kubelet root directory

Some storage tests deploy DaemonSets which hard-code /var/lib/kubelet as root
directory for kubelet registration and pod directory. There was already a
parameter which allowed specifying the root directory, just with a very
confusing name ("--volume-dir") and matching field name. A --kubelet-root-dir
parameters gets added because this may make it easier to find the parameter,
with the old name preserved as an alias for the same field for backwards
compatibility.

test/e2e/framework/test_context.go

@@ -77,7 +77,7 @@ type TestContextType struct {
 	KubeConfig         string
 	KubeContext        string
 	KubeAPIContentType string
-	KubeVolumeDir      string
+	KubeletRootDir     string
 	CertDir            string
 	Host               string
 	BearerToken        string `datapolicy:"token"`
@@ -337,7 +337,8 @@ func RegisterClusterFlags(flags *flag.FlagSet) {
 	flags.StringVar(&TestContext.KubeContext, clientcmd.FlagContext, "", "kubeconfig context to use/override. If unset, will use value from 'current-context'")
 	flags.StringVar(&TestContext.KubeAPIContentType, "kube-api-content-type", "application/vnd.kubernetes.protobuf", "ContentType used to communicate with apiserver")
 
-	flags.StringVar(&TestContext.KubeVolumeDir, "volume-dir", "/var/lib/kubelet", "Path to the directory containing the kubelet volumes.")
+	flags.StringVar(&TestContext.KubeletRootDir, "kubelet-root-dir", "/var/lib/kubelet", "The data directory of kubelet. Some tests (for example, CSI storage tests) deploy DaemonSets which need to know this value and cannot query it. Such tests only work in clusters where the data directory is the same on all nodes.")
+	flags.StringVar(&TestContext.KubeletRootDir, "volume-dir", "/var/lib/kubelet", "An alias for --kubelet-root-dir, kept for backwards compatibility.")
 	flags.StringVar(&TestContext.CertDir, "cert-dir", "", "Path to the directory containing the certs. Default is empty, which doesn't use certs.")
 	flags.StringVar(&TestContext.RepoRoot, "repo-root", "../../", "Root directory of kubernetes repository, for finding test files.")
 	// NOTE: Node E2E tests have this flag defined as well, but true by default.

test/e2e/node/security_context.go

@@ -234,8 +234,8 @@ func testPodSELinuxLabeling(f *framework.Framework, hostIPC bool, hostPID bool)
 
 	// Confirm that the file can be accessed from a second
 	// pod using host_path with the same MCS label
-	volumeHostPath := fmt.Sprintf("%s/pods/%s/volumes/kubernetes.io~empty-dir/%s", framework.TestContext.KubeVolumeDir, foundPod.UID, volumeName)
+	volumeHostPath := fmt.Sprintf("%s/pods/%s/volumes/kubernetes.io~empty-dir/%s", framework.TestContext.KubeletRootDir, foundPod.UID, volumeName)
-	ginkgo.By(fmt.Sprintf("confirming a container with the same label can read the file under --volume-dir=%s", framework.TestContext.KubeVolumeDir))
+	ginkgo.By(fmt.Sprintf("confirming a container with the same label can read the file under --kubelet-root-dir=%s", framework.TestContext.KubeletRootDir))
 	pod = scTestPod(hostIPC, hostPID)
 	pod.Spec.NodeName = foundPod.Spec.NodeName
 	volumeMounts := []v1.VolumeMount{

test/e2e/storage/utils/deployment.go

@@ -24,6 +24,7 @@ import (
 	v1 "k8s.io/api/core/v1"
 	storagev1 "k8s.io/api/storage/v1"
 	"k8s.io/kubernetes/test/e2e/framework"
+	e2eframework "k8s.io/kubernetes/test/e2e/framework"
 	e2epod "k8s.io/kubernetes/test/e2e/framework/pod"
 )
 
@@ -52,6 +53,10 @@ func PatchCSIDeployment(f *framework.Framework, o PatchCSIOptions, object interf
 	rename := o.OldDriverName != "" && o.NewDriverName != "" &&
 		o.OldDriverName != o.NewDriverName
 
+	substKubeletRootDir := func(s string) string {
+		return strings.ReplaceAll(s, "/var/lib/kubelet/", e2eframework.TestContext.KubeletRootDir+"/")
+	}
+
 	patchVolumes := func(volumes []v1.Volume) {
 		if !rename {
 			return
@@ -65,6 +70,8 @@ func PatchCSIDeployment(f *framework.Framework, o PatchCSIOptions, object interf
 				if file == o.OldDriverName {
 					*p = path.Join(dir, o.NewDriverName)
 				}
+				// Inject non-standard kubelet path.
+				*p = substKubeletRootDir(*p)
 			}
 		}
 	}
@@ -79,6 +86,15 @@ func PatchCSIDeployment(f *framework.Framework, o PatchCSIOptions, object interf
 					container.Args[e] = strings.Replace(container.Args[e], "/"+o.OldDriverName+"/", "/"+o.NewDriverName+"/", 1)
 				}
 			}
+
+			// Modify --kubelet-registration-path.
+			for e := range container.Args {
+				container.Args[e] = substKubeletRootDir(container.Args[e])
+			}
+			for e := range container.VolumeMounts {
+				container.VolumeMounts[e].MountPath = substKubeletRootDir(container.VolumeMounts[e].MountPath)
+			}
+
 			// Overwrite driver name resp. provider name
 			// by appending a parameter with the right
 			// value.