From 032a8863204c670e24b39a8f2889d659397c9ce6 Mon Sep 17 00:00:00 2001
From: Harry Zhang <harryzhang@zju.edu.cn>
Date: Sun, 8 May 2016 12:41:23 -0400
Subject: [PATCH] Only store top N images in status

---
 pkg/kubelet/kubelet.go      | 18 ++++++++++++++++++
 pkg/kubelet/kubelet_test.go | 25 +++++++++++++------------
 2 files changed, 31 insertions(+), 12 deletions(-)

diff --git a/pkg/kubelet/kubelet.go b/pkg/kubelet/kubelet.go
index 49884621646..714e0280ac6 100644
--- a/pkg/kubelet/kubelet.go
+++ b/pkg/kubelet/kubelet.go
@@ -151,6 +151,9 @@ const (
 
 	// Maximum period to wait for pod volume setup operations
 	maxWaitForVolumeOps = 20 * time.Minute
+
+	// maxImagesInStatus is the number of max images we store in image status.
+	maxImagesInNodeStatus = 50
 )
 
 // SyncHandler is an interface implemented by Kubelet, for testability
@@ -3096,6 +3099,12 @@ func (kl *Kubelet) setNodeStatusImages(node *api.Node) {
 	if err != nil {
 		glog.Errorf("Error getting image list: %v", err)
 	} else {
+		// sort the images from max to min, and only set top N images into the node status.
+		sort.Sort(ByImageSize(containerImages))
+		if maxImagesInNodeStatus < len(containerImages) {
+			containerImages = containerImages[0 : maxImagesInNodeStatus-1]
+		}
+
 		for _, image := range containerImages {
 			imagesOnNode = append(imagesOnNode, api.ContainerImage{
 				Names:     append(image.RepoTags, image.RepoDigests...),
@@ -3112,6 +3121,15 @@ func (kl *Kubelet) setNodeStatusGoRuntime(node *api.Node) {
 	node.Status.NodeInfo.Architecture = goRuntime.GOARCH
 }
 
+type ByImageSize []kubecontainer.Image
+
+// Sort from max to min
+func (a ByImageSize) Less(i, j int) bool {
+	return a[i].Size > a[j].Size
+}
+func (a ByImageSize) Len() int      { return len(a) }
+func (a ByImageSize) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
+
 // Set status for the node.
 func (kl *Kubelet) setNodeStatusInfo(node *api.Node) {
 	kl.setNodeStatusMachineInfo(node)
diff --git a/pkg/kubelet/kubelet_test.go b/pkg/kubelet/kubelet_test.go
index 9955269eed0..f93ef5b0c16 100644
--- a/pkg/kubelet/kubelet_test.go
+++ b/pkg/kubelet/kubelet_test.go
@@ -2435,14 +2435,14 @@ func TestUpdateNewNodeStatus(t *testing.T) {
 				{Type: api.NodeInternalIP, Address: "127.0.0.1"},
 			},
 			Images: []api.ContainerImage{
-				{
-					Names:     []string{"gcr.io/google_containers:v1", "gcr.io/google_containers:v2"},
-					SizeBytes: 123,
-				},
 				{
 					Names:     []string{"gcr.io/google_containers:v3", "gcr.io/google_containers:v4"},
 					SizeBytes: 456,
 				},
+				{
+					Names:     []string{"gcr.io/google_containers:v1", "gcr.io/google_containers:v2"},
+					SizeBytes: 123,
+				},
 			},
 		},
 	}
@@ -2685,15 +2685,16 @@ func TestUpdateExistingNodeStatus(t *testing.T) {
 				{Type: api.NodeLegacyHostIP, Address: "127.0.0.1"},
 				{Type: api.NodeInternalIP, Address: "127.0.0.1"},
 			},
+			// images will be sorted from max to min in node status.
 			Images: []api.ContainerImage{
-				{
-					Names:     []string{"gcr.io/google_containers:v1", "gcr.io/google_containers:v2"},
-					SizeBytes: 123,
-				},
 				{
 					Names:     []string{"gcr.io/google_containers:v3", "gcr.io/google_containers:v4"},
 					SizeBytes: 456,
 				},
+				{
+					Names:     []string{"gcr.io/google_containers:v1", "gcr.io/google_containers:v2"},
+					SizeBytes: 123,
+				},
 			},
 		},
 	}
@@ -2969,14 +2970,14 @@ func TestUpdateNodeStatusWithRuntimeStateError(t *testing.T) {
 				{Type: api.NodeInternalIP, Address: "127.0.0.1"},
 			},
 			Images: []api.ContainerImage{
-				{
-					Names:     []string{"gcr.io/google_containers:v1", "gcr.io/google_containers:v2"},
-					SizeBytes: 123,
-				},
 				{
 					Names:     []string{"gcr.io/google_containers:v3", "gcr.io/google_containers:v4"},
 					SizeBytes: 456,
 				},
+				{
+					Names:     []string{"gcr.io/google_containers:v1", "gcr.io/google_containers:v2"},
+					SizeBytes: 123,
+				},
 			},
 		},
 	}