add a flag to control the cap on images reported in node status

While I normally try to avoid adding flags, this is a short term
scalability fix for v1.11, and there are other long-term solutions in
the works, so we shouldn't commit to this in the v1beta1 Kubelet config.
Flags are our escape hatch.

cmd/kubelet/app/options/options.go

@@ -169,6 +169,9 @@ type KubeletFlags struct {
 	// bootstrapCheckpointPath is the path to the directory containing pod checkpoints to
 	// run on restore
 	BootstrapCheckpointPath string
+	// NodeStatusMaxImages caps the number of images reported in Node.Status.Images.
+	// This is an experimental, short-term flag to help with node scalability.
+	NodeStatusMaxImages int32
 
 	// DEPRECATED FLAGS
 	// minimumGCAge is the minimum age for a finished container before it is
@@ -244,6 +247,8 @@ func NewKubeletFlags() *KubeletFlags {
 		CAdvisorPort: 0,
 		// TODO(#58010:v1.13.0): Remove --allow-privileged, it is deprecated
 		AllowPrivileged: true,
+		// prior to the introduction of this flag, there was a hardcoded cap of 50 images
+		NodeStatusMaxImages: 50,
 	}
 }
 
@@ -255,6 +260,9 @@ func ValidateKubeletFlags(f *KubeletFlags) error {
 	if f.CAdvisorPort != 0 && utilvalidation.IsValidPortNum(int(f.CAdvisorPort)) != nil {
 		return fmt.Errorf("invalid configuration: CAdvisorPort (--cadvisor-port) %v must be between 0 and 65535, inclusive", f.CAdvisorPort)
 	}
+	if f.NodeStatusMaxImages < -1 {
+		return fmt.Errorf("invalid configuration: NodeStatusMaxImages (--node-status-max-images) must be -1 or greater")
+	}
 	return nil
 }
 
@@ -392,6 +400,7 @@ func (f *KubeletFlags) AddFlags(mainfs *pflag.FlagSet) {
 	fs.BoolVar(&f.ExitOnLockContention, "exit-on-lock-contention", f.ExitOnLockContention, "Whether kubelet should exit upon lock-file contention.")
 	fs.StringVar(&f.SeccompProfileRoot, "seccomp-profile-root", f.SeccompProfileRoot, "<Warning: Alpha feature> Directory path for seccomp profiles.")
 	fs.StringVar(&f.BootstrapCheckpointPath, "bootstrap-checkpoint-path", f.BootstrapCheckpointPath, "<Warning: Alpha feature> Path to to the directory where the checkpoints are stored")
+	fs.Int32Var(&f.NodeStatusMaxImages, "node-status-max-images", f.NodeStatusMaxImages, "<Warning: Alpha feature> The maximum number of images to report in Node.Status.Images. If -1 is specified, no cap will be applied. Default: 50")
 
 	// DEPRECATED FLAGS
 	fs.StringVar(&f.BootstrapKubeconfig, "experimental-bootstrap-kubeconfig", f.BootstrapKubeconfig, "")

cmd/kubelet/app/server.go

@@ -958,6 +958,7 @@ func RunKubelet(kubeFlags *options.KubeletFlags, kubeCfg *kubeletconfiginternal.
 		kubeFlags.NodeLabels,
 		kubeFlags.SeccompProfileRoot,
 		kubeFlags.BootstrapCheckpointPath,
+		kubeFlags.NodeStatusMaxImages,
 		stopCh)
 	if err != nil {
 		return fmt.Errorf("failed to create kubelet: %v", err)
@@ -1043,6 +1044,7 @@ func CreateAndInitKubelet(kubeCfg *kubeletconfiginternal.KubeletConfiguration,
 	nodeLabels map[string]string,
 	seccompProfileRoot string,
 	bootstrapCheckpointPath string,
+	nodeStatusMaxImages int32,
 	stopCh <-chan struct{}) (k kubelet.Bootstrap, err error) {
 	// TODO: block until all sources have delivered at least one update to the channel, or break the sync loop
 	// up into "per source" synchronizations
@@ -1077,6 +1079,7 @@ func CreateAndInitKubelet(kubeCfg *kubeletconfiginternal.KubeletConfiguration,
 		nodeLabels,
 		seccompProfileRoot,
 		bootstrapCheckpointPath,
+		nodeStatusMaxImages,
 		stopCh)
 	if err != nil {
 		return nil, err

pkg/kubelet/kubelet.go

@@ -219,7 +219,9 @@ type Builder func(kubeCfg *kubeletconfiginternal.KubeletConfiguration,
 	keepTerminatedPodVolumes bool,
 	nodeLabels map[string]string,
 	seccompProfileRoot string,
-	bootstrapCheckpointPath string) (Bootstrap, error)
+	bootstrapCheckpointPath string,
+	nodeStatusMaxImages int32,
+	stopCh <-chan struct{}) (Bootstrap, error)
 
 // Dependencies is a bin for things we might consider "injected dependencies" -- objects constructed
 // at runtime that are necessary for running the Kubelet. This is a temporary solution for grouping
@@ -345,6 +347,7 @@ func NewMainKubelet(kubeCfg *kubeletconfiginternal.KubeletConfiguration,
 	nodeLabels map[string]string,
 	seccompProfileRoot string,
 	bootstrapCheckpointPath string,
+	nodeStatusMaxImages int32,
 	stopCh <-chan struct{}) (*Kubelet, error) {
 	if rootDirectory == "" {
 		return nil, fmt.Errorf("invalid root directory %q", rootDirectory)
@@ -535,6 +538,7 @@ func NewMainKubelet(kubeCfg *kubeletconfiginternal.KubeletConfiguration,
 		iptablesDropBit:                         int(kubeCfg.IPTablesDropBit),
 		experimentalHostUserNamespaceDefaulting: utilfeature.DefaultFeatureGate.Enabled(features.ExperimentalHostUserNamespaceDefaultingGate),
 		keepTerminatedPodVolumes:                keepTerminatedPodVolumes,
+		nodeStatusMaxImages:                     nodeStatusMaxImages,
 	}
 
 	if klet.cloud != nil {
@@ -1157,6 +1161,9 @@ type Kubelet struct {
 	// such as device plugins or CSI plugins. It discovers plugins by monitoring inotify events under the
 	// directory returned by kubelet.getPluginsDir()
 	pluginWatcher pluginwatcher.Watcher
+
+	// This flag sets a maximum number of images to report in the node status.
+	nodeStatusMaxImages int32
 }
 
 func allGlobalUnicastIPs() ([]net.IP, error) {

pkg/kubelet/kubelet_node_status.go

@@ -49,9 +49,6 @@ import (
 )
 
 const (
-	// maxImagesInNodeStatus is the number of max images we store in image status.
-	maxImagesInNodeStatus = 50
-
 	// maxNamesPerImageInNodeStatus is max number of names per image stored in
 	// the node status.
 	maxNamesPerImageInNodeStatus = 5
@@ -721,8 +718,9 @@ func (kl *Kubelet) setNodeStatusImages(node *v1.Node) {
 		return
 	}
 	// sort the images from max to min, and only set top N images into the node status.
-	if maxImagesInNodeStatus < len(containerImages) {
-		containerImages = containerImages[0:maxImagesInNodeStatus]
+	if int(kl.nodeStatusMaxImages) > -1 &&
+		int(kl.nodeStatusMaxImages) < len(containerImages) {
+		containerImages = containerImages[0:kl.nodeStatusMaxImages]
 	}
 
 	for _, image := range containerImages {

pkg/kubelet/kubelet_node_status_test.go

@@ -60,8 +60,8 @@ const (
 	maxImageTagsForTest = 20
 )
 
-// generateTestingImageList generate randomly generated image list and corresponding expectedImageList.
-func generateTestingImageList(count int) ([]kubecontainer.Image, []v1.ContainerImage) {
+// generateTestingImageLists generate randomly generated image list and corresponding expectedImageList.
+func generateTestingImageLists(count int, maxImages int) ([]kubecontainer.Image, []v1.ContainerImage) {
 	// imageList is randomly generated image list
 	var imageList []kubecontainer.Image
 	for ; count > 0; count-- {
@@ -73,7 +73,12 @@ func generateTestingImageList(count int) ([]kubecontainer.Image, []v1.ContainerI
 		imageList = append(imageList, imageItem)
 	}
 
-	// expectedImageList is generated by imageList according to size and maxImagesInNodeStatus
+	expectedImageList := makeExpectedImageList(imageList, maxImages)
+	return imageList, expectedImageList
+}
+
+func makeExpectedImageList(imageList []kubecontainer.Image, maxImages int) []v1.ContainerImage {
+	// expectedImageList is generated by imageList according to size and maxImages
 	// 1. sort the imageList by size
 	sort.Sort(sliceutils.ByImageSize(imageList))
 	// 2. convert sorted imageList to v1.ContainerImage list
@@ -86,8 +91,11 @@ func generateTestingImageList(count int) ([]kubecontainer.Image, []v1.ContainerI
 
 		expectedImageList = append(expectedImageList, apiImage)
 	}
-	// 3. only returns the top maxImagesInNodeStatus images in expectedImageList
-	return imageList, expectedImageList[0:maxImagesInNodeStatus]
+	// 3. only returns the top maxImages images in expectedImageList
+	if maxImages == -1 { // -1 means no limit
+		return expectedImageList
+	}
+	return expectedImageList[0:maxImages]
 }
 
 func generateImageTags() []string {
@@ -299,165 +307,190 @@ func sortNodeAddresses(addrs sortableNodeAddress) {
 }
 
 func TestUpdateNewNodeStatus(t *testing.T) {
-	// generate one more than maxImagesInNodeStatus in inputImageList
-	inputImageList, expectedImageList := generateTestingImageList(maxImagesInNodeStatus + 1)
-	testKubelet := newTestKubeletWithImageList(
-		t, inputImageList, false /* controllerAttachDetachEnabled */)
-	defer testKubelet.Cleanup()
-	kubelet := testKubelet.kubelet
-	kubelet.kubeClient = nil // ensure only the heartbeat client is used
-	kubelet.containerManager = &localCM{
-		ContainerManager: cm.NewStubContainerManager(),
-		allocatableReservation: v1.ResourceList{
-			v1.ResourceCPU:              *resource.NewMilliQuantity(200, resource.DecimalSI),
-			v1.ResourceMemory:           *resource.NewQuantity(100E6, resource.BinarySI),
-			v1.ResourceEphemeralStorage: *resource.NewQuantity(2000, resource.BinarySI),
+	cases := []struct {
+		desc                string
+		nodeStatusMaxImages int32
+	}{
+		{
+			desc:                "5 image limit",
+			nodeStatusMaxImages: 5,
 		},
-		capacity: v1.ResourceList{
-			v1.ResourceCPU:              *resource.NewMilliQuantity(2000, resource.DecimalSI),
-			v1.ResourceMemory:           *resource.NewQuantity(10E9, resource.BinarySI),
-			v1.ResourceEphemeralStorage: *resource.NewQuantity(5000, resource.BinarySI),
-		},
-	}
-	kubeClient := testKubelet.fakeKubeClient
-	existingNode := v1.Node{ObjectMeta: metav1.ObjectMeta{Name: testKubeletHostname}}
-	kubeClient.ReactionChain = fake.NewSimpleClientset(&v1.NodeList{Items: []v1.Node{existingNode}}).ReactionChain
-	machineInfo := &cadvisorapi.MachineInfo{
-		MachineID:      "123",
-		SystemUUID:     "abc",
-		BootID:         "1b3",
-		NumCores:       2,
-		MemoryCapacity: 10E9, // 10G
-	}
-	mockCadvisor := testKubelet.fakeCadvisor
-	mockCadvisor.On("Start").Return(nil)
-	mockCadvisor.On("MachineInfo").Return(machineInfo, nil)
-	versionInfo := &cadvisorapi.VersionInfo{
-		KernelVersion:      "3.16.0-0.bpo.4-amd64",
-		ContainerOsVersion: "Debian GNU/Linux 7 (wheezy)",
-	}
-	mockCadvisor.On("ImagesFsInfo").Return(cadvisorapiv2.FsInfo{
-		Usage:     400,
-		Capacity:  5000,
-		Available: 600,
-	}, nil)
-	mockCadvisor.On("RootFsInfo").Return(cadvisorapiv2.FsInfo{
-		Usage:     400,
-		Capacity:  5000,
-		Available: 600,
-	}, nil)
-	mockCadvisor.On("VersionInfo").Return(versionInfo, nil)
-	maxAge := 0 * time.Second
-	options := cadvisorapiv2.RequestOptions{IdType: cadvisorapiv2.TypeName, Count: 2, Recursive: false, MaxAge: &maxAge}
-	mockCadvisor.On("ContainerInfoV2", "/", options).Return(map[string]cadvisorapiv2.ContainerInfo{}, nil)
-	kubelet.machineInfo = machineInfo
-
-	expectedNode := &v1.Node{
-		ObjectMeta: metav1.ObjectMeta{Name: testKubeletHostname},
-		Spec:       v1.NodeSpec{},
-		Status: v1.NodeStatus{
-			Conditions: []v1.NodeCondition{
-				{
-					Type:               v1.NodeOutOfDisk,
-					Status:             v1.ConditionFalse,
-					Reason:             "KubeletHasSufficientDisk",
-					Message:            fmt.Sprintf("kubelet has sufficient disk space available"),
-					LastHeartbeatTime:  metav1.Time{},
-					LastTransitionTime: metav1.Time{},
-				},
-				{
-					Type:               v1.NodeMemoryPressure,
-					Status:             v1.ConditionFalse,
-					Reason:             "KubeletHasSufficientMemory",
-					Message:            fmt.Sprintf("kubelet has sufficient memory available"),
-					LastHeartbeatTime:  metav1.Time{},
-					LastTransitionTime: metav1.Time{},
-				},
-				{
-					Type:               v1.NodeDiskPressure,
-					Status:             v1.ConditionFalse,
-					Reason:             "KubeletHasNoDiskPressure",
-					Message:            fmt.Sprintf("kubelet has no disk pressure"),
-					LastHeartbeatTime:  metav1.Time{},
-					LastTransitionTime: metav1.Time{},
-				},
-				{
-					Type:               v1.NodePIDPressure,
-					Status:             v1.ConditionFalse,
-					Reason:             "KubeletHasSufficientPID",
-					Message:            fmt.Sprintf("kubelet has sufficient PID available"),
-					LastHeartbeatTime:  metav1.Time{},
-					LastTransitionTime: metav1.Time{},
-				},
-				{
-					Type:               v1.NodeReady,
-					Status:             v1.ConditionTrue,
-					Reason:             "KubeletReady",
-					Message:            fmt.Sprintf("kubelet is posting ready status"),
-					LastHeartbeatTime:  metav1.Time{},
-					LastTransitionTime: metav1.Time{},
-				},
-			},
-			NodeInfo: v1.NodeSystemInfo{
-				MachineID:               "123",
-				SystemUUID:              "abc",
-				BootID:                  "1b3",
-				KernelVersion:           "3.16.0-0.bpo.4-amd64",
-				OSImage:                 "Debian GNU/Linux 7 (wheezy)",
-				OperatingSystem:         goruntime.GOOS,
-				Architecture:            goruntime.GOARCH,
-				ContainerRuntimeVersion: "test://1.5.0",
-				KubeletVersion:          version.Get().String(),
-				KubeProxyVersion:        version.Get().String(),
-			},
-			Capacity: v1.ResourceList{
-				v1.ResourceCPU:              *resource.NewMilliQuantity(2000, resource.DecimalSI),
-				v1.ResourceMemory:           *resource.NewQuantity(10E9, resource.BinarySI),
-				v1.ResourcePods:             *resource.NewQuantity(0, resource.DecimalSI),
-				v1.ResourceEphemeralStorage: *resource.NewQuantity(5000, resource.BinarySI),
-			},
-			Allocatable: v1.ResourceList{
-				v1.ResourceCPU:              *resource.NewMilliQuantity(1800, resource.DecimalSI),
-				v1.ResourceMemory:           *resource.NewQuantity(9900E6, resource.BinarySI),
-				v1.ResourcePods:             *resource.NewQuantity(0, resource.DecimalSI),
-				v1.ResourceEphemeralStorage: *resource.NewQuantity(3000, resource.BinarySI),
-			},
-			Addresses: []v1.NodeAddress{
-				{Type: v1.NodeInternalIP, Address: "127.0.0.1"},
-				{Type: v1.NodeHostName, Address: testKubeletHostname},
-			},
-			Images: expectedImageList,
+		{
+			desc:                "no image limit",
+			nodeStatusMaxImages: -1,
 		},
 	}
 
-	kubelet.updateRuntimeUp()
-	assert.NoError(t, kubelet.updateNodeStatus())
-	actions := kubeClient.Actions()
-	require.Len(t, actions, 2)
-	require.True(t, actions[1].Matches("patch", "nodes"))
-	require.Equal(t, actions[1].GetSubresource(), "status")
+	for _, tc := range cases {
+		t.Run(tc.desc, func(t *testing.T) {
+			// generate one more in inputImageList than we configure the Kubelet to report,
+			// or 5 images if unlimited
+			numTestImages := int(tc.nodeStatusMaxImages) + 1
+			if tc.nodeStatusMaxImages == -1 {
+				numTestImages = 5
+			}
+			inputImageList, expectedImageList := generateTestingImageLists(numTestImages, int(tc.nodeStatusMaxImages))
+			testKubelet := newTestKubeletWithImageList(
+				t, inputImageList, false /* controllerAttachDetachEnabled */)
+			defer testKubelet.Cleanup()
+			kubelet := testKubelet.kubelet
+			kubelet.nodeStatusMaxImages = tc.nodeStatusMaxImages
+			kubelet.kubeClient = nil // ensure only the heartbeat client is used
+			kubelet.containerManager = &localCM{
+				ContainerManager: cm.NewStubContainerManager(),
+				allocatableReservation: v1.ResourceList{
+					v1.ResourceCPU:              *resource.NewMilliQuantity(200, resource.DecimalSI),
+					v1.ResourceMemory:           *resource.NewQuantity(100E6, resource.BinarySI),
+					v1.ResourceEphemeralStorage: *resource.NewQuantity(2000, resource.BinarySI),
+				},
+				capacity: v1.ResourceList{
+					v1.ResourceCPU:              *resource.NewMilliQuantity(2000, resource.DecimalSI),
+					v1.ResourceMemory:           *resource.NewQuantity(10E9, resource.BinarySI),
+					v1.ResourceEphemeralStorage: *resource.NewQuantity(5000, resource.BinarySI),
+				},
+			}
+			kubeClient := testKubelet.fakeKubeClient
+			existingNode := v1.Node{ObjectMeta: metav1.ObjectMeta{Name: testKubeletHostname}}
+			kubeClient.ReactionChain = fake.NewSimpleClientset(&v1.NodeList{Items: []v1.Node{existingNode}}).ReactionChain
+			machineInfo := &cadvisorapi.MachineInfo{
+				MachineID:      "123",
+				SystemUUID:     "abc",
+				BootID:         "1b3",
+				NumCores:       2,
+				MemoryCapacity: 10E9, // 10G
+			}
+			mockCadvisor := testKubelet.fakeCadvisor
+			mockCadvisor.On("Start").Return(nil)
+			mockCadvisor.On("MachineInfo").Return(machineInfo, nil)
+			versionInfo := &cadvisorapi.VersionInfo{
+				KernelVersion:      "3.16.0-0.bpo.4-amd64",
+				ContainerOsVersion: "Debian GNU/Linux 7 (wheezy)",
+			}
+			mockCadvisor.On("ImagesFsInfo").Return(cadvisorapiv2.FsInfo{
+				Usage:     400,
+				Capacity:  5000,
+				Available: 600,
+			}, nil)
+			mockCadvisor.On("RootFsInfo").Return(cadvisorapiv2.FsInfo{
+				Usage:     400,
+				Capacity:  5000,
+				Available: 600,
+			}, nil)
+			mockCadvisor.On("VersionInfo").Return(versionInfo, nil)
+			maxAge := 0 * time.Second
+			options := cadvisorapiv2.RequestOptions{IdType: cadvisorapiv2.TypeName, Count: 2, Recursive: false, MaxAge: &maxAge}
+			mockCadvisor.On("ContainerInfoV2", "/", options).Return(map[string]cadvisorapiv2.ContainerInfo{}, nil)
+			kubelet.machineInfo = machineInfo
 
-	updatedNode, err := applyNodeStatusPatch(&existingNode, actions[1].(core.PatchActionImpl).GetPatch())
-	assert.NoError(t, err)
-	for i, cond := range updatedNode.Status.Conditions {
-		assert.False(t, cond.LastHeartbeatTime.IsZero(), "LastHeartbeatTime for %v condition is zero", cond.Type)
-		assert.False(t, cond.LastTransitionTime.IsZero(), "LastTransitionTime for %v condition  is zero", cond.Type)
-		updatedNode.Status.Conditions[i].LastHeartbeatTime = metav1.Time{}
-		updatedNode.Status.Conditions[i].LastTransitionTime = metav1.Time{}
+			expectedNode := &v1.Node{
+				ObjectMeta: metav1.ObjectMeta{Name: testKubeletHostname},
+				Spec:       v1.NodeSpec{},
+				Status: v1.NodeStatus{
+					Conditions: []v1.NodeCondition{
+						{
+							Type:               v1.NodeOutOfDisk,
+							Status:             v1.ConditionFalse,
+							Reason:             "KubeletHasSufficientDisk",
+							Message:            fmt.Sprintf("kubelet has sufficient disk space available"),
+							LastHeartbeatTime:  metav1.Time{},
+							LastTransitionTime: metav1.Time{},
+						},
+						{
+							Type:               v1.NodeMemoryPressure,
+							Status:             v1.ConditionFalse,
+							Reason:             "KubeletHasSufficientMemory",
+							Message:            fmt.Sprintf("kubelet has sufficient memory available"),
+							LastHeartbeatTime:  metav1.Time{},
+							LastTransitionTime: metav1.Time{},
+						},
+						{
+							Type:               v1.NodeDiskPressure,
+							Status:             v1.ConditionFalse,
+							Reason:             "KubeletHasNoDiskPressure",
+							Message:            fmt.Sprintf("kubelet has no disk pressure"),
+							LastHeartbeatTime:  metav1.Time{},
+							LastTransitionTime: metav1.Time{},
+						},
+						{
+							Type:               v1.NodePIDPressure,
+							Status:             v1.ConditionFalse,
+							Reason:             "KubeletHasSufficientPID",
+							Message:            fmt.Sprintf("kubelet has sufficient PID available"),
+							LastHeartbeatTime:  metav1.Time{},
+							LastTransitionTime: metav1.Time{},
+						},
+						{
+							Type:               v1.NodeReady,
+							Status:             v1.ConditionTrue,
+							Reason:             "KubeletReady",
+							Message:            fmt.Sprintf("kubelet is posting ready status"),
+							LastHeartbeatTime:  metav1.Time{},
+							LastTransitionTime: metav1.Time{},
+						},
+					},
+					NodeInfo: v1.NodeSystemInfo{
+						MachineID:               "123",
+						SystemUUID:              "abc",
+						BootID:                  "1b3",
+						KernelVersion:           "3.16.0-0.bpo.4-amd64",
+						OSImage:                 "Debian GNU/Linux 7 (wheezy)",
+						OperatingSystem:         goruntime.GOOS,
+						Architecture:            goruntime.GOARCH,
+						ContainerRuntimeVersion: "test://1.5.0",
+						KubeletVersion:          version.Get().String(),
+						KubeProxyVersion:        version.Get().String(),
+					},
+					Capacity: v1.ResourceList{
+						v1.ResourceCPU:              *resource.NewMilliQuantity(2000, resource.DecimalSI),
+						v1.ResourceMemory:           *resource.NewQuantity(10E9, resource.BinarySI),
+						v1.ResourcePods:             *resource.NewQuantity(0, resource.DecimalSI),
+						v1.ResourceEphemeralStorage: *resource.NewQuantity(5000, resource.BinarySI),
+					},
+					Allocatable: v1.ResourceList{
+						v1.ResourceCPU:              *resource.NewMilliQuantity(1800, resource.DecimalSI),
+						v1.ResourceMemory:           *resource.NewQuantity(9900E6, resource.BinarySI),
+						v1.ResourcePods:             *resource.NewQuantity(0, resource.DecimalSI),
+						v1.ResourceEphemeralStorage: *resource.NewQuantity(3000, resource.BinarySI),
+					},
+					Addresses: []v1.NodeAddress{
+						{Type: v1.NodeInternalIP, Address: "127.0.0.1"},
+						{Type: v1.NodeHostName, Address: testKubeletHostname},
+					},
+					Images: expectedImageList,
+				},
+			}
+
+			kubelet.updateRuntimeUp()
+			assert.NoError(t, kubelet.updateNodeStatus())
+			actions := kubeClient.Actions()
+			require.Len(t, actions, 2)
+			require.True(t, actions[1].Matches("patch", "nodes"))
+			require.Equal(t, actions[1].GetSubresource(), "status")
+
+			updatedNode, err := applyNodeStatusPatch(&existingNode, actions[1].(core.PatchActionImpl).GetPatch())
+			assert.NoError(t, err)
+			for i, cond := range updatedNode.Status.Conditions {
+				assert.False(t, cond.LastHeartbeatTime.IsZero(), "LastHeartbeatTime for %v condition is zero", cond.Type)
+				assert.False(t, cond.LastTransitionTime.IsZero(), "LastTransitionTime for %v condition  is zero", cond.Type)
+				updatedNode.Status.Conditions[i].LastHeartbeatTime = metav1.Time{}
+				updatedNode.Status.Conditions[i].LastTransitionTime = metav1.Time{}
+			}
+
+			// Version skew workaround. See: https://github.com/kubernetes/kubernetes/issues/16961
+			assert.Equal(t, v1.NodeReady, updatedNode.Status.Conditions[len(updatedNode.Status.Conditions)-1].Type,
+				"NotReady should be last")
+			assert.Len(t, updatedNode.Status.Images, len(expectedImageList))
+			assert.True(t, apiequality.Semantic.DeepEqual(expectedNode, updatedNode), "%s", diff.ObjectDiff(expectedNode, updatedNode))
+		})
 	}
-
-	// Version skew workaround. See: https://github.com/kubernetes/kubernetes/issues/16961
-	assert.Equal(t, v1.NodeReady, updatedNode.Status.Conditions[len(updatedNode.Status.Conditions)-1].Type,
-		"NotReady should be last")
-	assert.Len(t, updatedNode.Status.Images, maxImagesInNodeStatus)
-	assert.True(t, apiequality.Semantic.DeepEqual(expectedNode, updatedNode), "%s", diff.ObjectDiff(expectedNode, updatedNode))
 }
 
 func TestUpdateExistingNodeStatus(t *testing.T) {
 	testKubelet := newTestKubelet(t, false /* controllerAttachDetachEnabled */)
 	defer testKubelet.Cleanup()
 	kubelet := testKubelet.kubelet
-	kubelet.kubeClient = nil // ensure only the heartbeat client is used
+	kubelet.nodeStatusMaxImages = 5 // don't truncate the image list that gets constructed by hand for this test
+	kubelet.kubeClient = nil        // ensure only the heartbeat client is used
 	kubelet.containerManager = &localCM{
 		ContainerManager: cm.NewStubContainerManager(),
 		allocatableReservation: v1.ResourceList{
@@ -742,7 +775,8 @@ func TestUpdateNodeStatusWithRuntimeStateError(t *testing.T) {
 	testKubelet := newTestKubelet(t, false /* controllerAttachDetachEnabled */)
 	defer testKubelet.Cleanup()
 	kubelet := testKubelet.kubelet
-	kubelet.kubeClient = nil // ensure only the heartbeat client is used
+	kubelet.nodeStatusMaxImages = 5 // don't truncate the image list that gets constructed by hand for this test
+	kubelet.kubeClient = nil        // ensure only the heartbeat client is used
 	kubelet.containerManager = &localCM{
 		ContainerManager: cm.NewStubContainerManager(),
 		allocatableReservation: v1.ResourceList{
@@ -1214,12 +1248,15 @@ func TestTryRegisterWithApiServer(t *testing.T) {
 }
 
 func TestUpdateNewNodeStatusTooLargeReservation(t *testing.T) {
-	// generate one more than maxImagesInNodeStatus in inputImageList
-	inputImageList, _ := generateTestingImageList(maxImagesInNodeStatus + 1)
+	const nodeStatusMaxImages = 5
+
+	// generate one more in inputImageList than we configure the Kubelet to report
+	inputImageList, _ := generateTestingImageLists(nodeStatusMaxImages+1, nodeStatusMaxImages)
 	testKubelet := newTestKubeletWithImageList(
 		t, inputImageList, false /* controllerAttachDetachEnabled */)
 	defer testKubelet.Cleanup()
 	kubelet := testKubelet.kubelet
+	kubelet.nodeStatusMaxImages = nodeStatusMaxImages
 	kubelet.kubeClient = nil // ensure only the heartbeat client is used
 	kubelet.containerManager = &localCM{
 		ContainerManager: cm.NewStubContainerManager(),