rkt: Unmarshal the ENTRYPOINT/CMD from jsons instead of strings.

Using json makes this robust to ENTRYPOINT/CMD that contains space.

Also removed 'RemainAfterExit' option, originally this option is
useful when we implement GetPods() by 'systemctl list-units'.
However since we are using rkt API service now, it's no longer needed.

pkg/kubelet/rkt/rkt.go

@@ -426,11 +426,17 @@ func setApp(imgManifest *appcschema.ImageManifest, c *api.Container, opts *kubec
 	var command, args []string
 	cmd, ok := imgManifest.Annotations.Get(appcDockerEntrypoint)
 	if ok {
-		command = strings.Fields(cmd)
+		err := json.Unmarshal([]byte(cmd), &command)
+		if err != nil {
+			return fmt.Errorf("cannot unmarshal ENTRYPOINT %q: %v", cmd, err)
+		}
 	}
 	ag, ok := imgManifest.Annotations.Get(appcDockerCmd)
 	if ok {
-		args = strings.Fields(ag)
+		err := json.Unmarshal([]byte(ag), &args)
+		if err != nil {
+			return fmt.Errorf("cannot unmarshal CMD %q: %v", ag, err)
+		}
 	}
 	userCommand, userArgs := kubecontainer.ExpandContainerCommandAndArgs(c, opts.Envs)
 
@@ -814,8 +820,6 @@ func (r *Runtime) preparePod(pod *api.Pod, pullSecrets []api.Secret) (string, *k
 	// TODO handle pod.Spec.HostIPC
 
 	units := []*unit.UnitOption{
-		// This makes the service show up for 'systemctl list-units' even if it exits successfully.
-		newUnitOption("Service", "RemainAfterExit", "true"),
 		newUnitOption("Service", "ExecStart", runPrepared),
 		// This enables graceful stop.
 		newUnitOption("Service", "KillMode", "mixed"),

pkg/kubelet/rkt/rkt_test.go

@@ -766,8 +766,16 @@ func baseApp(t *testing.T) *appctypes.App {
 
 func baseImageManifest(t *testing.T) *appcschema.ImageManifest {
 	img := &appcschema.ImageManifest{App: baseApp(t)}
-	img.Annotations.Set(*appctypes.MustACIdentifier(appcDockerEntrypoint), "/bin/foo")
+	entrypoint, err := json.Marshal([]string{"/bin/foo"})
-	img.Annotations.Set(*appctypes.MustACIdentifier(appcDockerCmd), "bar")
+	if err != nil {
+		t.Fatal(err)
+	}
+	cmd, err := json.Marshal([]string{"bar"})
+	if err != nil {
+		t.Fatal(err)
+	}
+	img.Annotations.Set(*appctypes.MustACIdentifier(appcDockerEntrypoint), string(entrypoint))
+	img.Annotations.Set(*appctypes.MustACIdentifier(appcDockerCmd), string(cmd))
 	return img
 }