Allow mount to work when the uid/gid of docker changes

cmd/minikube/cmd/mount.go

@@ -45,8 +45,8 @@ var mountIP string
 var mountVersion string
 var mountType string
 var isKill bool
-var uid int
-var gid int
+var uid string
+var gid string
 var mSize int
 var options []string
 var mode uint
@@ -144,8 +144,8 @@ var mountCmd = &cobra.Command{
 		console.OutStyle("mounting", "Mounting host path %s into VM as %s ...", hostPath, vmPath)
 		console.OutStyle("mount-options", "Mount options:")
 		console.OutStyle("option", "Type:     %s", cfg.Type)
-		console.OutStyle("option", "UID:      %d", cfg.UID)
-		console.OutStyle("option", "GID:      %d", cfg.GID)
+		console.OutStyle("option", "UID:      %s", cfg.UID)
+		console.OutStyle("option", "GID:      %s", cfg.GID)
 		console.OutStyle("option", "Version:  %s", cfg.Version)
 		console.OutStyle("option", "MSize:    %d", cfg.MSize)
 		console.OutStyle("option", "Mode:     %o (%s)", cfg.Mode, cfg.Mode)
@@ -194,8 +194,8 @@ func init() {
 	mountCmd.Flags().StringVar(&mountType, "type", nineP, "Specify the mount filesystem type (supported types: 9p)")
 	mountCmd.Flags().StringVar(&mountVersion, "9p-version", constants.DefaultMountVersion, "Specify the 9p version that the mount should use")
 	mountCmd.Flags().BoolVar(&isKill, "kill", false, "Kill the mount process spawned by minikube start")
-	mountCmd.Flags().IntVar(&uid, "uid", 1001, "Default user id used for the mount")
-	mountCmd.Flags().IntVar(&gid, "gid", 1001, "Default group id used for the mount")
+	mountCmd.Flags().StringVar(&uid, "uid", "docker", "Default user id used for the mount")
+	mountCmd.Flags().StringVar(&gid, "gid", "docker", "Default group id used for the mount")
 	mountCmd.Flags().UintVar(&mode, "mode", 0755, "File permissions used for the mount")
 	mountCmd.Flags().StringSliceVar(&options, "options", []string{}, "Additional mount options, such as cache=fscache")
 	mountCmd.Flags().IntVar(&mSize, "msize", constants.DefaultMsize, "The number of bytes to use for 9p packet payload")

pkg/minikube/cluster/mount.go

@@ -31,9 +31,9 @@ type MountConfig struct {
 	// Type is the filesystem type (Typically 9p)
 	Type string
 	// UID is the User ID which this path will be mounted as
-	UID int
+	UID string
 	// GID is the Group ID which this path will be mounted as
-	GID int
+	GID string
 	// Version is the 9P protocol version. Valid options: 9p2000, 9p200.u, 9p2000.L
 	Version string
 	// MSize is the number of bytes to use for 9p packet payload
@@ -65,11 +65,38 @@ func Mount(h hostRunner, source string, target string, c *MountConfig) error {
 	return nil
 }
 
+// returns either a raw UID number, or the subshell to resolve it.
+func resolveUID(id string) string {
+	_, err := strconv.ParseInt(id, 10, 64)
+	if err == nil {
+		return id
+	}
+	// Preserve behavior where unset ID == 0
+	if id == "" {
+		return "0"
+	}
+	return fmt.Sprintf(`$(id -u %s)`, id)
+}
+
+// returns either a raw GID number, or the subshell to resolve it.
+func resolveGID(id string) string {
+	_, err := strconv.ParseInt(id, 10, 64)
+	if err == nil {
+		return id
+	}
+	// Preserve behavior where unset ID == 0
+	if id == "" {
+		return "0"
+	}
+	// Because `getent` isn't part of our ISO
+	return fmt.Sprintf(`$(grep ^%s: /etc/group | cut -d: -f3)`, id)
+}
+
 // mntCmd returns a mount command based on a config.
 func mntCmd(source string, target string, c *MountConfig) string {
 	options := map[string]string{
-		"dfltgid": strconv.Itoa(c.GID),
-		"dfltuid": strconv.Itoa(c.UID),
+		"dfltgid": resolveGID(c.GID),
+		"dfltuid": resolveUID(c.UID),
 	}
 	if c.Port != 0 {
 		options["port"] = strconv.Itoa(c.Port)

pkg/minikube/cluster/mount_test.go

@@ -58,11 +58,21 @@ func TestMount(t *testing.T) {
 				"sudo mkdir -m 700 -p target && sudo mount -t 9p -o dfltgid=0,dfltuid=0 src target",
 			},
 		},
+		{
+			name:   "named uid",
+			source: "src",
+			target: "target",
+			cfg:    &MountConfig{Type: "9p", Mode: os.FileMode(0700), UID: "docker", GID: "docker"},
+			want: []string{
+				"findmnt -T target && sudo umount target || true",
+				"sudo mkdir -m 700 -p target && sudo mount -t 9p -o dfltgid=$(grep ^docker: /etc/group | cut -d: -f3),dfltuid=$(id -u docker) src target",
+			},
+		},
 		{
 			name:   "everything",
 			source: "10.0.0.1",
 			target: "/target",
-			cfg: &MountConfig{Type: "9p", Mode: os.FileMode(0777), UID: 82, GID: 72, Version: "9p2000.u", Options: map[string]string{
+			cfg: &MountConfig{Type: "9p", Mode: os.FileMode(0777), UID: "82", GID: "72", Version: "9p2000.u", Options: map[string]string{
 				"noextend": "",
 				"cache":    "fscache",
 			}},

test/integration/mount_test.go

@@ -56,6 +56,8 @@ func testMounting(t *testing.T) {
 	} else {
 		mountCmd = fmt.Sprintf("mount %s:/mount-9p", tempDir)
 	}
+
+	t.Logf("Starting mount: %s", mountCmd)
 	cmd, _, _ := minikubeRunner.RunDaemon2(mountCmd)
 	defer func() {
 		err := cmd.Process.Kill()
@@ -81,12 +83,14 @@ func testMounting(t *testing.T) {
 
 	// Create the pods we need outside the main test loop.
 	setupTest := func() error {
+		t.Logf("Deploying pod from: %s", podPath)
 		if _, err := kubectlRunner.RunCommand([]string{"create", "-f", podPath}); err != nil {
 			return err
 		}
 		return nil
 	}
 	defer func() {
+		t.Logf("Deleting pod from: %s", podPath)
 		if out, err := kubectlRunner.RunCommand([]string{"delete", "-f", podPath}); err != nil {
 			t.Logf("delete -f %s failed: %v\noutput: %s\n", podPath, err, out)
 		}
@@ -104,6 +108,7 @@ func testMounting(t *testing.T) {
 	if err := pkgutil.WaitForPodsWithLabelRunning(client, "default", selector); err != nil {
 		t.Fatalf("Error waiting for busybox mount pod to be up: %v", err)
 	}
+	t.Logf("Pods appear to be running")
 
 	mountTest := func() error {
 		path := filepath.Join(tempDir, "frompod")
@@ -161,5 +166,4 @@ func testMounting(t *testing.T) {
 	if err := util.Retry(t, mountTest, 5*time.Second, 40); err != nil {
 		t.Fatalf("mountTest failed with error: %v", err)
 	}
-
 }