Merge pull request kubernetes#119652 from lixd/kubelet_image_gc

fix kubelet image gc

pkg/kubelet/container/testing/fake_runtime.go

@@ -364,7 +364,13 @@ func (f *FakeRuntime) ListImages(_ context.Context) ([]kubecontainer.Image, erro
 	defer f.Unlock()
 
 	f.CalledFunctions = append(f.CalledFunctions, "ListImages")
-	return f.ImageList, f.Err
+	return snapshot(f.ImageList), f.Err
+}
+
+func snapshot(imageList []kubecontainer.Image) []kubecontainer.Image {
+	result := make([]kubecontainer.Image, len(imageList))
+	copy(result, imageList)
+	return result
 }
 
 func (f *FakeRuntime) RemoveImage(_ context.Context, image kubecontainer.ImageSpec) error {

pkg/kubelet/images/image_gc_manager.go

@@ -118,9 +118,6 @@ type realImageGCManager struct {
 	// Reference to this node.
 	nodeRef *v1.ObjectReference
 
-	// Track initialization
-	initialized bool
-
 	// imageCache is the cache of latest image list.
 	imageCache imageCache
 
@@ -196,7 +193,6 @@ func NewImageGCManager(runtime container.Runtime, statsProvider StatsProvider, r
 		statsProvider: statsProvider,
 		recorder:      recorder,
 		nodeRef:       nodeRef,
-		initialized:   false,
 		tracer:        tracer,
 	}
 
@@ -206,16 +202,9 @@ func NewImageGCManager(runtime container.Runtime, statsProvider StatsProvider, r
 func (im *realImageGCManager) Start() {
 	ctx := context.Background()
 	go wait.Until(func() {
-		// Initial detection make detected time "unknown" in the past.
-		var ts time.Time
-		if im.initialized {
-			ts = time.Now()
-		}
-		_, err := im.detectImages(ctx, ts)
+		_, err := im.detectImages(ctx, time.Now())
 		if err != nil {
 			klog.InfoS("Failed to monitor images", "err", err)
-		} else {
-			im.initialized = true
 		}
 	}, 5*time.Minute, wait.NeverStop)
 

pkg/kubelet/images/image_gc_manager_test.go

@@ -516,6 +516,41 @@ func TestDeleteUnusedImagesRemoveAllUnusedImages(t *testing.T) {
 	assert.Len(fakeRuntime.ImageList, 1)
 }
 
+func TestDeleteUnusedImagesLimitByImageLiveTime(t *testing.T) {
+	ctx := context.Background()
+	mockCtrl := gomock.NewController(t)
+	defer mockCtrl.Finish()
+	mockStatsProvider := statstest.NewMockProvider(mockCtrl)
+
+	manager, fakeRuntime := newRealImageGCManager(ImageGCPolicy{
+		MinAge: time.Second * 3, // set minAge to 3 seconds,
+	}, mockStatsProvider)
+	fakeRuntime.ImageList = []container.Image{
+		makeImage(0, 1024),
+		makeImage(1, 2048),
+		makeImage(2, 2048),
+	}
+	fakeRuntime.AllPodList = []*containertest.FakePod{
+		{Pod: &container.Pod{
+			Containers: []*container.Container{
+				makeContainer(2),
+			},
+		}},
+	}
+	// start to detect images
+	manager.Start()
+	// try to delete images, but images are not old enough,so no image will be deleted
+	err := manager.DeleteUnusedImages(ctx)
+	assert := assert.New(t)
+	require.NoError(t, err)
+	assert.Len(fakeRuntime.ImageList, 3)
+	// sleep 3 seconds, then images will be old enough to be deleted
+	time.Sleep(time.Second * 3)
+	err = manager.DeleteUnusedImages(ctx)
+	require.NoError(t, err)
+	assert.Len(fakeRuntime.ImageList, 1)
+}
+
 func TestFreeSpaceRemoveByLeastRecentlyUsed(t *testing.T) {
 	ctx := context.Background()
 	mockCtrl := gomock.NewController(t)