Report out of disk as a node condition when node goes out of disk.

Define a new out of disk node condition and use it to report when node
goes out of disk.

Make a copy of loop range clause variable in node listers so that it
is available outside the for loop.

Also update/implement unit tests.

pkg/api/types.go

@@ -1491,6 +1491,9 @@ type NodeConditionType string
 const (
 	// NodeReady means kubelet is healthy and ready to accept pods.
 	NodeReady NodeConditionType = "Ready"
+	// NodeOutOfDisk means the kubelet will not accept new pods due to insufficient free disk
+	// space on the node.
+	NodeOutOfDisk NodeConditionType = "OutOfDisk"
 )
 
 type NodeCondition struct {

pkg/api/v1/types.go

@@ -1868,6 +1868,9 @@ type NodeConditionType string
 const (
 	// NodeReady means kubelet is healthy and ready to accept pods.
 	NodeReady NodeConditionType = "Ready"
+	// NodeOutOfDisk means the kubelet will not accept new pods due to insufficient free disk
+	// space on the node.
+	NodeOutOfDisk NodeConditionType = "OutOfDisk"
 )
 
 // NodeCondition contains condition infromation for a node.

pkg/client/cache/listers.go

@@ -136,7 +136,9 @@ func (s storeToNodeConditionLister) List() (nodes api.NodeList, err error) {
 		// Get the last condition of the required type
 		for _, cond := range node.Status.Conditions {
 			if cond.Type == s.conditionType {
-				nodeCondition = &cond
+				condCopy := cond
+				nodeCondition = &condCopy
+				break
 			} else {
 				glog.V(4).Infof("Ignoring condition type %v for node %v", cond.Type, node.Name)
 			}

pkg/kubelet/kubelet.go

@@ -2389,6 +2389,8 @@ func (kl *Kubelet) syncNetworkStatus() {
 
 // setNodeStatus fills in the Status fields of the given Node, overwriting
 // any fields that are currently set.
+// TODO(madhusudancs): Simplify the logic for setting node conditions and
+// refactor the node status condtion code out to a different file.
 func (kl *Kubelet) setNodeStatus(node *api.Node) error {
 	// Set addresses for the node.
 	if kl.cloud != nil {
@@ -2549,6 +2551,61 @@ func (kl *Kubelet) setNodeStatus(node *api.Node) error {
 			kl.recordNodeStatusEvent("NodeNotReady")
 		}
 	}
+
+	var nodeOODCondition *api.NodeCondition
+
+	// Check if NodeOutOfDisk condition already exists and if it does, just pick it up for update.
+	for i := range node.Status.Conditions {
+		if node.Status.Conditions[i].Type == api.NodeOutOfDisk {
+			nodeOODCondition = &node.Status.Conditions[i]
+		}
+	}
+
+	newOODCondition := false
+	// If the NodeOutOfDisk condition doesn't exist, create one.
+	if nodeOODCondition == nil {
+		nodeOODCondition = &api.NodeCondition{
+			Type:               api.NodeOutOfDisk,
+			Status:             api.ConditionUnknown,
+			LastTransitionTime: currentTime,
+		}
+		// nodeOODCondition cannot be appended to node.Status.Conditions here because it gets
+		// copied to the slice. So if we append nodeOODCondition to the slice here none of the
+		// updates we make to nodeOODCondition below are reflected in the slice.
+		newOODCondition = true
+	}
+
+	// Update the heartbeat time irrespective of all the conditions.
+	nodeOODCondition.LastHeartbeatTime = currentTime
+
+	// Note: The conditions below take care of the case when a new NodeOutOfDisk condition is
+	// created and as well as the case when the condition already exists. When a new condition
+	// is created its status is set to api.ConditionUnknown which matches either
+	// nodeOODCondition.Status != api.ConditionTrue or
+	// nodeOODCondition.Status != api.ConditionFalse in the conditions below depending on whether
+	// the kubelet is out of disk or not.
+	if kl.isOutOfDisk() {
+		if nodeOODCondition.Status != api.ConditionTrue {
+			nodeOODCondition.Status = api.ConditionTrue
+			nodeOODCondition.Reason = "KubeletOutOfDisk"
+			nodeOODCondition.Message = "out of disk space"
+			nodeOODCondition.LastTransitionTime = currentTime
+			kl.recordNodeStatusEvent("NodeOutOfDisk")
+		}
+	} else {
+		if nodeOODCondition.Status != api.ConditionFalse {
+			nodeOODCondition.Status = api.ConditionFalse
+			nodeOODCondition.Reason = "KubeletHasSufficientDisk"
+			nodeOODCondition.Message = "kubelet has sufficient disk space available"
+			nodeOODCondition.LastTransitionTime = currentTime
+			kl.recordNodeStatusEvent("NodeHasSufficientDisk")
+		}
+	}
+
+	if newOODCondition {
+		node.Status.Conditions = append(node.Status.Conditions, *nodeOODCondition)
+	}
+
 	if oldNodeUnschedulable != node.Spec.Unschedulable {
 		if node.Spec.Unschedulable {
 			kl.recordNodeStatusEvent("NodeNotSchedulable")

pkg/kubelet/kubelet_test.go

@@ -2504,6 +2504,23 @@ func TestUpdateNewNodeStatus(t *testing.T) {
 		DockerVersion:      "1.5.0",
 	}
 	mockCadvisor.On("VersionInfo").Return(versionInfo, nil)
+
+	// Create a new DiskSpaceManager with a new policy. This new manager along with the mock
+	// FsInfo values added to Cadvisor should make the kubelet report that it has sufficient
+	// disk space.
+	dockerimagesFsInfo := cadvisorapiv2.FsInfo{Capacity: 500 * mb, Available: 200 * mb}
+	rootFsInfo := cadvisorapiv2.FsInfo{Capacity: 500 * mb, Available: 200 * mb}
+	mockCadvisor.On("DockerImagesFsInfo").Return(dockerimagesFsInfo, nil)
+	mockCadvisor.On("RootFsInfo").Return(rootFsInfo, nil)
+
+	dsp := DiskSpacePolicy{DockerFreeDiskMB: 100, RootFreeDiskMB: 100}
+	diskSpaceManager, err := newDiskSpaceManager(mockCadvisor, dsp)
+	if err != nil {
+		t.Fatalf("can't update disk space manager: %v", err)
+	}
+	diskSpaceManager.Unfreeze()
+	kubelet.diskSpaceManager = diskSpaceManager
+
 	expectedNode := &api.Node{
 		ObjectMeta: api.ObjectMeta{Name: testKubeletHostname},
 		Spec:       api.NodeSpec{},
@@ -2517,6 +2534,14 @@ func TestUpdateNewNodeStatus(t *testing.T) {
 					LastHeartbeatTime:  unversioned.Time{},
 					LastTransitionTime: unversioned.Time{},
 				},
+				{
+					Type:               api.NodeOutOfDisk,
+					Status:             api.ConditionFalse,
+					Reason:             "KubeletHasSufficientDisk",
+					Message:            fmt.Sprintf("kubelet has sufficient disk space available"),
+					LastHeartbeatTime:  unversioned.Time{},
+					LastTransitionTime: unversioned.Time{},
+				},
 			},
 			NodeInfo: api.NodeSystemInfo{
 				MachineID:               "123",
@@ -2555,14 +2580,17 @@ func TestUpdateNewNodeStatus(t *testing.T) {
 	if !ok {
 		t.Errorf("unexpected object type")
 	}
-	if updatedNode.Status.Conditions[0].LastHeartbeatTime.IsZero() {
-		t.Errorf("unexpected zero last probe timestamp")
+	for i, cond := range updatedNode.Status.Conditions {
+		if cond.LastHeartbeatTime.IsZero() {
+			t.Errorf("unexpected zero last probe timestamp for %v condition", cond.Type)
+		}
+		if cond.LastTransitionTime.IsZero() {
+			t.Errorf("unexpected zero last transition timestamp for %v condition", cond.Type)
+		}
+		updatedNode.Status.Conditions[i].LastHeartbeatTime = unversioned.Time{}
+		updatedNode.Status.Conditions[i].LastTransitionTime = unversioned.Time{}
 	}
-	if updatedNode.Status.Conditions[0].LastTransitionTime.IsZero() {
-		t.Errorf("unexpected zero last transition timestamp")
-	}
-	updatedNode.Status.Conditions[0].LastHeartbeatTime = unversioned.Time{}
-	updatedNode.Status.Conditions[0].LastTransitionTime = unversioned.Time{}
+
 	if !reflect.DeepEqual(expectedNode, updatedNode) {
 		t.Errorf("unexpected objects: %s", util.ObjectDiff(expectedNode, updatedNode))
 	}
@@ -2586,6 +2614,14 @@ func TestUpdateExistingNodeStatus(t *testing.T) {
 						LastHeartbeatTime:  unversioned.Date(2012, 1, 1, 0, 0, 0, 0, time.UTC),
 						LastTransitionTime: unversioned.Date(2012, 1, 1, 0, 0, 0, 0, time.UTC),
 					},
+					{
+						Type:               api.NodeOutOfDisk,
+						Status:             api.ConditionTrue,
+						Reason:             "KubeletOutOfDisk",
+						Message:            "out of disk space",
+						LastHeartbeatTime:  unversioned.Date(2012, 1, 1, 0, 0, 0, 0, time.UTC),
+						LastTransitionTime: unversioned.Date(2012, 1, 1, 0, 0, 0, 0, time.UTC),
+					},
 				},
 				Capacity: api.ResourceList{
 					api.ResourceCPU:    *resource.NewMilliQuantity(3000, resource.DecimalSI),
@@ -2610,6 +2646,22 @@ func TestUpdateExistingNodeStatus(t *testing.T) {
 		DockerVersion:      "1.5.0",
 	}
 	mockCadvisor.On("VersionInfo").Return(versionInfo, nil)
+
+	// Create a new DiskSpaceManager with a new policy. This new manager along with the mock FsInfo
+	// values added to Cadvisor should make the kubelet report that it is out of disk space.
+	dockerimagesFsInfo := cadvisorapiv2.FsInfo{Capacity: 500 * mb, Available: 70 * mb}
+	rootFsInfo := cadvisorapiv2.FsInfo{Capacity: 500 * mb, Available: 50 * mb}
+	mockCadvisor.On("DockerImagesFsInfo").Return(dockerimagesFsInfo, nil)
+	mockCadvisor.On("RootFsInfo").Return(rootFsInfo, nil)
+
+	dsp := DiskSpacePolicy{DockerFreeDiskMB: 100, RootFreeDiskMB: 100}
+	diskSpaceManager, err := newDiskSpaceManager(mockCadvisor, dsp)
+	if err != nil {
+		t.Fatalf("can't update disk space manager: %v", err)
+	}
+	diskSpaceManager.Unfreeze()
+	kubelet.diskSpaceManager = diskSpaceManager
+
 	expectedNode := &api.Node{
 		ObjectMeta: api.ObjectMeta{Name: testKubeletHostname},
 		Spec:       api.NodeSpec{},
@@ -2623,6 +2675,14 @@ func TestUpdateExistingNodeStatus(t *testing.T) {
 					LastHeartbeatTime:  unversioned.Time{}, // placeholder
 					LastTransitionTime: unversioned.Time{}, // placeholder
 				},
+				{
+					Type:               api.NodeOutOfDisk,
+					Status:             api.ConditionTrue,
+					Reason:             "KubeletOutOfDisk",
+					Message:            "out of disk space",
+					LastHeartbeatTime:  unversioned.Time{}, // placeholder
+					LastTransitionTime: unversioned.Time{}, // placeholder
+				},
 			},
 			NodeInfo: api.NodeSystemInfo{
 				MachineID:               "123",
@@ -2662,16 +2722,18 @@ func TestUpdateExistingNodeStatus(t *testing.T) {
 	if !ok {
 		t.Errorf("unexpected object type")
 	}
-	// Expect LastProbeTime to be updated to Now, while LastTransitionTime to be the same.
-	if reflect.DeepEqual(updatedNode.Status.Conditions[0].LastHeartbeatTime.Rfc3339Copy().UTC(), unversioned.Date(2012, 1, 1, 0, 0, 0, 0, time.UTC).Time) {
-		t.Errorf("expected \n%v\n, got \n%v", unversioned.Now(), unversioned.Date(2012, 1, 1, 0, 0, 0, 0, time.UTC))
+	for i, cond := range updatedNode.Status.Conditions {
+		// Expect LastProbeTime to be updated to Now, while LastTransitionTime to be the same.
+		if old := unversioned.Date(2012, 1, 1, 0, 0, 0, 0, time.UTC).Time; reflect.DeepEqual(cond.LastHeartbeatTime.Rfc3339Copy().UTC(), old) {
+			t.Errorf("Condition %v LastProbeTime: expected \n%v\n, got \n%v", cond.Type, unversioned.Now(), old)
+		}
+		if got, want := cond.LastTransitionTime.Rfc3339Copy().UTC(), unversioned.Date(2012, 1, 1, 0, 0, 0, 0, time.UTC).Time; !reflect.DeepEqual(got, want) {
+			t.Errorf("Condition %v LastTransitionTime: expected \n%#v\n, got \n%#v", cond.Type, want, got)
+		}
+		updatedNode.Status.Conditions[i].LastHeartbeatTime = unversioned.Time{}
+		updatedNode.Status.Conditions[i].LastTransitionTime = unversioned.Time{}
 	}
-	if !reflect.DeepEqual(updatedNode.Status.Conditions[0].LastTransitionTime.Rfc3339Copy().UTC(), unversioned.Date(2012, 1, 1, 0, 0, 0, 0, time.UTC).Time) {
-		t.Errorf("expected \n%#v\n, got \n%#v", updatedNode.Status.Conditions[0].LastTransitionTime.Rfc3339Copy(),
-			unversioned.Date(2012, 1, 1, 0, 0, 0, 0, time.UTC))
-	}
-	updatedNode.Status.Conditions[0].LastHeartbeatTime = unversioned.Time{}
-	updatedNode.Status.Conditions[0].LastTransitionTime = unversioned.Time{}
+
 	if !reflect.DeepEqual(expectedNode, updatedNode) {
 		t.Errorf("expected \n%v\n, got \n%v", expectedNode, updatedNode)
 	}
@@ -2705,6 +2767,22 @@ func TestUpdateNodeStatusWithoutContainerRuntime(t *testing.T) {
 	}
 	mockCadvisor.On("VersionInfo").Return(versionInfo, nil)
 
+	// Create a new DiskSpaceManager with a new policy. This new manager along with the
+	// mock FsInfo values assigned to Cadvisor should make the kubelet report that it has
+	// sufficient disk space.
+	dockerimagesFsInfo := cadvisorapiv2.FsInfo{Capacity: 500 * mb, Available: 200 * mb}
+	rootFsInfo := cadvisorapiv2.FsInfo{Capacity: 500 * mb, Available: 200 * mb}
+	mockCadvisor.On("DockerImagesFsInfo").Return(dockerimagesFsInfo, nil)
+	mockCadvisor.On("RootFsInfo").Return(rootFsInfo, nil)
+
+	dsp := DiskSpacePolicy{DockerFreeDiskMB: 100, RootFreeDiskMB: 100}
+	diskSpaceManager, err := newDiskSpaceManager(mockCadvisor, dsp)
+	if err != nil {
+		t.Fatalf("can't update disk space manager: %v", err)
+	}
+	diskSpaceManager.Unfreeze()
+	kubelet.diskSpaceManager = diskSpaceManager
+
 	expectedNode := &api.Node{
 		ObjectMeta: api.ObjectMeta{Name: testKubeletHostname},
 		Spec:       api.NodeSpec{},
@@ -2718,6 +2796,14 @@ func TestUpdateNodeStatusWithoutContainerRuntime(t *testing.T) {
 					LastHeartbeatTime:  unversioned.Time{},
 					LastTransitionTime: unversioned.Time{},
 				},
+				{
+					Type:               api.NodeOutOfDisk,
+					Status:             api.ConditionFalse,
+					Reason:             "KubeletHasSufficientDisk",
+					Message:            "kubelet has sufficient disk space available",
+					LastHeartbeatTime:  unversioned.Time{},
+					LastTransitionTime: unversioned.Time{},
+				},
 			},
 			NodeInfo: api.NodeSystemInfo{
 				MachineID:               "123",
@@ -2758,14 +2844,17 @@ func TestUpdateNodeStatusWithoutContainerRuntime(t *testing.T) {
 		t.Errorf("unexpected action type.  expected UpdateAction, got %#v", actions[1])
 	}
 
-	if updatedNode.Status.Conditions[0].LastHeartbeatTime.IsZero() {
-		t.Errorf("unexpected zero last probe timestamp")
+	for i, cond := range updatedNode.Status.Conditions {
+		if cond.LastHeartbeatTime.IsZero() {
+			t.Errorf("unexpected zero last probe timestamp")
+		}
+		if cond.LastTransitionTime.IsZero() {
+			t.Errorf("unexpected zero last transition timestamp")
+		}
+		updatedNode.Status.Conditions[i].LastHeartbeatTime = unversioned.Time{}
+		updatedNode.Status.Conditions[i].LastTransitionTime = unversioned.Time{}
 	}
-	if updatedNode.Status.Conditions[0].LastTransitionTime.IsZero() {
-		t.Errorf("unexpected zero last transition timestamp")
-	}
-	updatedNode.Status.Conditions[0].LastHeartbeatTime = unversioned.Time{}
-	updatedNode.Status.Conditions[0].LastTransitionTime = unversioned.Time{}
+
 	if !reflect.DeepEqual(expectedNode, updatedNode) {
 		t.Errorf("unexpected objects: %s", util.ObjectDiff(expectedNode, updatedNode))
 	}