Merge pull request #11128 from justinsb/e2e_pd_contents

e2e: Add test to pd that disk contents are preserved

test/e2e/pd.go

@@ -18,10 +18,12 @@ package e2e
 
 import (
 	"fmt"
+	math_rand "math/rand"
 	"os/exec"
 	"strings"
 	"time"
 
+	"bytes"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/latest"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/client"
@@ -86,6 +88,12 @@ var _ = Describe("Pod Disks", func() {
 
 		expectNoError(waitForPodRunning(c, host0Pod.Name))
 
+		testFile := "/testpd/tracker"
+		testFileContents := fmt.Sprintf("%v", math_rand.Int())
+
+		expectNoError(writeFileOnPod(c, host0Pod.Name, testFile, testFileContents))
+		Logf("Wrote value: %v", testFileContents)
+
 		By("deleting host0Pod")
 		expectNoError(podClient.Delete(host0Pod.Name, nil), "Failed to delete host0Pod")
 
@@ -95,6 +103,12 @@ var _ = Describe("Pod Disks", func() {
 
 		expectNoError(waitForPodRunning(c, host1Pod.Name))
 
+		v, err := readFileOnPod(c, host1Pod.Name, testFile)
+		expectNoError(err)
+		Logf("Read value: %v", v)
+
+		Expect(strings.TrimSpace(v)).To(Equal(strings.TrimSpace(testFileContents)))
+
 		By("deleting host1Pod")
 		expectNoError(podClient.Delete(host1Pod.Name, nil), "Failed to delete host1Pod")
 
@@ -173,6 +187,48 @@ var _ = Describe("Pod Disks", func() {
 	})
 })
 
+func kubectlExec(namespace string, podName string, args ...string) ([]byte, []byte, error) {
+	var stdout, stderr bytes.Buffer
+	cmdArgs := []string{"exec", fmt.Sprintf("--namespace=%v", namespace), podName}
+	cmdArgs = append(cmdArgs, args...)
+
+	cmd := kubectlCmd(cmdArgs...)
+	cmd.Stdout, cmd.Stderr = &stdout, &stderr
+
+	Logf("Running '%s %s'", cmd.Path, strings.Join(cmd.Args, " "))
+	err := cmd.Run()
+	return stdout.Bytes(), stderr.Bytes(), err
+}
+
+// Write a file using kubectl exec echo <contents> > <path>
+// Because of the primitive technique we're using here, we only allow ASCII alphanumeric characters
+func writeFileOnPod(c *client.Client, podName string, path string, contents string) error {
+	By("writing a file in the container")
+	allowedCharacters := "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
+	for _, c := range contents {
+		if !strings.ContainsRune(allowedCharacters, c) {
+			return fmt.Errorf("Unsupported character in string to write: %v", c)
+		}
+	}
+	command := fmt.Sprintf("echo '%s' > '%s'", contents, path)
+	stdout, stderr, err := kubectlExec(api.NamespaceDefault, podName, "--", "/bin/sh", "-c", command)
+	if err != nil {
+		Logf("error running kubectl exec to write file: %v\nstdout=%v\nstderr=%v)", err, string(stdout), string(stderr))
+	}
+	return err
+}
+
+// Read a file using kubectl exec cat <path>
+func readFileOnPod(c *client.Client, podName string, path string) (string, error) {
+	By("reading a file in the container")
+
+	stdout, stderr, err := kubectlExec(api.NamespaceDefault, podName, "--", "cat", path)
+	if err != nil {
+		Logf("error running kubectl exec to read file: %v\nstdout=%v\nstderr=%v)", err, string(stdout), string(stderr))
+	}
+	return string(stdout), err
+}
+
 func createPD() (string, error) {
 	if testContext.Provider == "gce" || testContext.Provider == "gke" {
 		pdName := fmt.Sprintf("%s-%s", testContext.prefix, string(util.NewUUID()))
@@ -244,8 +300,9 @@ func testPDPod(diskName, targetHost string, readOnly bool) *api.Pod {
 		Spec: api.PodSpec{
 			Containers: []api.Container{
 				{
-					Name:  "testpd",
-					Image: "gcr.io/google_containers/pause",
+					Name:    "testpd",
+					Image:   "gcr.io/google_containers/busybox",
+					Command: []string{"sleep", "600"},
 					VolumeMounts: []api.VolumeMount{
 						{
 							Name:      "testpd",