@@ -1,6 +1,7 @@

 package image // import "github.com/docker/docker/image"

 import (

+	"fmt"

 	"runtime"

 	"testing"

@@ -171,6 +172,20 @@ func TestGetAndSetLastUpdated(t *testing.T) {

 	assert.Equal(t, updated.IsZero(), false)

 }

+func TestStoreLen(t *testing.T) {

+	store, cleanup := defaultImageStore(t)

+	defer cleanup()

+

+	expected := 10

+	for i := 0; i < expected; i++ {

+		_, err := store.Create([]byte(fmt.Sprintf(`{"comment": "abc%d", "rootfs": {"type": "layers"}}`, i)))

+		assert.NoError(t, err)

+	}

+	numImages := store.Len()

+	assert.Equal(t, expected, numImages)

+	assert.Equal(t, len(store.Map()), numImages)

+}

+

 type mockLayerGetReleaser struct{}

 func (ls *mockLayerGetReleaser) Get(layer.ChainID) (layer.Layer, error) {

@@ -263,11 +263,15 @@ func (r *remote) startContainerd() error {

 func (r *remote) monitorConnection(monitor *containerd.Client) {

 	var transientFailureCount = 0

-	ticker := time.NewTicker(500 * time.Millisecond)

-	defer ticker.Stop()

-

 	for {

-		<-ticker.C

+		select {

+		case <-r.shutdownContext.Done():

+			r.logger.Info("stopping healthcheck following graceful shutdown")

+			monitor.Close()

+			return

+		case <-time.After(500 * time.Millisecond):

+		}

+

 		ctx, cancel := context.WithTimeout(r.shutdownContext, healthCheckTimeout)

 		_, err := monitor.IsServing(ctx)

 		cancel()