Use mountpoint as image fs identifier.

Signed-off-by: Lantao Liu <lantaol@google.com>

pkg/server/container_stats_list.go

@@ -83,8 +83,8 @@ func (c *criContainerdService) getContainerMetrics(
 	}
 	cs.WritableLayer = &runtime.FilesystemUsage{
 		Timestamp: sn.Timestamp,
-		StorageId: &runtime.StorageIdentifier{
-			Uuid: c.imageFSUUID,
+		FsId: &runtime.FilesystemIdentifier{
+			Mountpoint: c.imageFSPath,
 		},
 		UsedBytes:  &runtime.UInt64Value{Value: usedBytes},
 		InodesUsed: &runtime.UInt64Value{Value: inodesUsed},

pkg/server/imagefs_info.go

@@ -42,7 +42,7 @@ func (c *criContainerdService) ImageFsInfo(ctx context.Context, r *runtime.Image
 		ImageFilesystems: []*runtime.FilesystemUsage{
 			{
 				Timestamp:  timestamp,
-				StorageId:  &runtime.StorageIdentifier{Uuid: c.imageFSUUID},
+				FsId:       &runtime.FilesystemIdentifier{Mountpoint: c.imageFSPath},
 				UsedBytes:  &runtime.UInt64Value{Value: usedBytes},
 				InodesUsed: &runtime.UInt64Value{Value: inodesUsed},
 			},

pkg/server/imagefs_info_test.go

@@ -55,7 +55,7 @@ func TestImageFsInfo(t *testing.T) {
 	}
 	expected := &runtime.FilesystemUsage{
 		Timestamp:  123456,
-		StorageId:  &runtime.StorageIdentifier{Uuid: testImageFSUUID},
+		FsId:       &runtime.FilesystemIdentifier{Mountpoint: testImageFSPath},
 		UsedBytes:  &runtime.UInt64Value{Value: 30},
 		InodesUsed: &runtime.UInt64Value{Value: 300},
 	}

pkg/server/service.go

@@ -33,7 +33,6 @@ import (
 	"github.com/opencontainers/selinux/go-selinux"
 	"github.com/sirupsen/logrus"
 	"golang.org/x/net/context"
-	"golang.org/x/sys/unix"
 	"google.golang.org/grpc"
 	runtime "k8s.io/kubernetes/pkg/kubelet/apis/cri/runtime/v1alpha2"
 	"k8s.io/kubernetes/pkg/kubelet/server/streaming"
@@ -76,8 +75,8 @@ type CRIContainerdService interface {
 type criContainerdService struct {
 	// config contains all configurations.
 	config options.Config
-	// imageFSUUID is the device uuid of image filesystem.
-	imageFSUUID string
+	// imageFSPath is the path to image filesystem.
+	imageFSPath string
 	// apparmorEnabled indicates whether apparmor is enabled.
 	apparmorEnabled bool
 	// seccompEnabled indicates whether seccomp is enabled.
@@ -138,16 +137,8 @@ func NewCRIContainerdService(config options.Config) (CRIContainerdService, error
 		selinux.SetDisabled()
 	}
 
-	if !c.config.SkipImageFSUUID {
-		imageFSPath := imageFSPath(config.ContainerdRootDir, config.ContainerdConfig.Snapshotter)
-		c.imageFSUUID, err = c.getDeviceUUID(imageFSPath)
-		if err != nil {
-			return nil, fmt.Errorf("failed to get imagefs uuid of %q: %v", imageFSPath, err)
-		}
-		logrus.Infof("Get device uuid %q for image filesystem %q", c.imageFSUUID, imageFSPath)
-	} else {
-		logrus.Warn("Skip retrieving imagefs UUID, kubelet will not be able to get imagefs capacity or perform imagefs disk eviction.")
-	}
+	c.imageFSPath = imageFSPath(config.ContainerdRootDir, config.ContainerdConfig.Snapshotter)
+	logrus.Infof("Get image filesystem path %q", c.imageFSPath)
 
 	c.netPlugin, err = ocicni.InitCNI(config.NetworkPluginConfDir, config.NetworkPluginBinDir)
 	if err != nil {
@@ -293,16 +284,6 @@ func (c *criContainerdService) Close() error {
 	return nil
 }
 
-// getDeviceUUID gets device uuid for a given path.
-func (c *criContainerdService) getDeviceUUID(path string) (string, error) {
-	mount, err := c.os.LookupMount(path)
-	if err != nil {
-		return "", err
-	}
-	rdev := unix.Mkdev(uint32(mount.Major), uint32(mount.Minor))
-	return c.os.DeviceUUID(rdev)
-}
-
 // imageFSPath returns containerd image filesystem path.
 // Note that if containerd changes directory layout, we also needs to change this.
 func imageFSPath(rootDir, snapshotter string) string {

pkg/server/service_test.go

@@ -33,7 +33,7 @@ const (
 	// TODO(random-liu): Change this to image name after we have complete image
 	// management unit test framework.
 	testSandboxImage = "sha256:c75bebcdd211f41b3a460c7bf82970ed6c75acaab9cd4c9a4e125b03ca113798"
-	testImageFSUUID  = "test-image-fs-uuid"
+	testImageFSPath  = "/test/image/fs/path"
 )
 
 // newTestCRIContainerdService creates a fake criContainerdService for test.
@@ -45,7 +45,7 @@ func newTestCRIContainerdService() *criContainerdService {
 				SandboxImage: testSandboxImage,
 			},
 		},
-		imageFSUUID:        testImageFSUUID,
+		imageFSPath:        testImageFSPath,
 		os:                 ostesting.NewFakeOS(),
 		sandboxStore:       sandboxstore.NewStore(),
 		imageStore:         imagestore.NewStore(),