Support deleting all unused images

pkg/kubelet/image_manager.go

@@ -18,6 +18,7 @@ package kubelet
 
 import (
 	"fmt"
+	"math"
 	"sort"
 	"sync"
 	"time"
@@ -46,6 +47,9 @@ type imageManager interface {
 
 	GetImageList() ([]kubecontainer.Image, error)
 
+	// Delete all unused images and returns the number of bytes freed. The number of bytes freed is always returned.
+	DeleteUnusedImages() (int64, error)
+
 	// TODO(vmarmol): Have this subsume pulls as well.
 }
 
@@ -248,6 +252,10 @@ func (im *realImageManager) GarbageCollect() error {
 	return nil
 }
 
+func (im *realImageManager) DeleteUnusedImages() (int64, error) {
+	return im.freeSpace(math.MaxInt64, time.Now())
+}
+
 // Tries to free bytesToFree worth of images on the disk.
 //
 // Returns the number of bytes free and an error if any occurred. The number of

pkg/kubelet/image_manager_test.go

@@ -238,6 +238,28 @@ func TestFreeSpaceImagesInUseContainersAreIgnored(t *testing.T) {
 	assert.Len(fakeRuntime.ImageList, 1)
 }
 
+func TestDeleteUnusedImagesRemoveAllUnusedImages(t *testing.T) {
+	manager, fakeRuntime, _ := newRealImageManager(ImageGCPolicy{})
+	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),
+			},
+		}},
+	}
+
+	spaceFreed, err := manager.DeleteUnusedImages()
+	assert := assert.New(t)
+	require.NoError(t, err)
+	assert.EqualValues(3072, spaceFreed)
+	assert.Len(fakeRuntime.ImageList, 1)
+}
+
 func TestFreeSpaceRemoveByLeastRecentlyUsed(t *testing.T) {
 	manager, fakeRuntime, _ := newRealImageManager(ImageGCPolicy{})
 	fakeRuntime.ImageList = []container.Image{