fix an issue that scheduling doesn't respect NodeLost status of a node

- if Node is in UnknowStatus, apply unreachable taint with NoSchedule effect
- some internal data structure refactoring
- update unit test

pkg/controller/nodelifecycle/node_lifecycle_controller.go

@@ -77,40 +77,35 @@ var (
 		Effect: v1.TaintEffectNoExecute,
 	}
 
-	nodeConditionToTaintKeyStatusMap = map[v1.NodeConditionType]struct {
-		taintKey string
-		// noScheduleStatus is the condition under which the node should be tainted as not schedulable for this
-		// NodeConditionType
-		noScheduleStatus v1.ConditionStatus
-	}{
+	// map {NodeConditionType: {ConditionStatus: TaintKey}}
+	// represents which NodeConditionType under which ConditionStatus should be
+	// tainted with which TaintKey
+	// for certain NodeConditionType, there are multiple {ConditionStatus,TaintKey} pairs
+	nodeConditionToTaintKeyStatusMap = map[v1.NodeConditionType]map[v1.ConditionStatus]string{
 		v1.NodeReady: {
-			taintKey:         algorithm.TaintNodeNotReady,
-			noScheduleStatus: v1.ConditionFalse,
+			v1.ConditionFalse:   algorithm.TaintNodeNotReady,
+			v1.ConditionUnknown: algorithm.TaintNodeUnreachable,
 		},
 		v1.NodeMemoryPressure: {
-			taintKey:         algorithm.TaintNodeMemoryPressure,
-			noScheduleStatus: v1.ConditionTrue,
+			v1.ConditionTrue: algorithm.TaintNodeMemoryPressure,
 		},
 		v1.NodeOutOfDisk: {
-			taintKey:         algorithm.TaintNodeOutOfDisk,
-			noScheduleStatus: v1.ConditionTrue,
+			v1.ConditionTrue: algorithm.TaintNodeOutOfDisk,
 		},
 		v1.NodeDiskPressure: {
-			taintKey:         algorithm.TaintNodeDiskPressure,
-			noScheduleStatus: v1.ConditionTrue,
+			v1.ConditionTrue: algorithm.TaintNodeDiskPressure,
 		},
 		v1.NodeNetworkUnavailable: {
-			taintKey:         algorithm.TaintNodeNetworkUnavailable,
-			noScheduleStatus: v1.ConditionTrue,
+			v1.ConditionTrue: algorithm.TaintNodeNetworkUnavailable,
 		},
 		v1.NodePIDPressure: {
-			taintKey:         algorithm.TaintNodePIDPressure,
-			noScheduleStatus: v1.ConditionTrue,
+			v1.ConditionTrue: algorithm.TaintNodePIDPressure,
 		},
 	}
 
 	taintKeyToNodeConditionMap = map[string]v1.NodeConditionType{
 		algorithm.TaintNodeNotReady:           v1.NodeReady,
+		algorithm.TaintNodeUnreachable:        v1.NodeReady,
 		algorithm.TaintNodeNetworkUnavailable: v1.NodeNetworkUnavailable,
 		algorithm.TaintNodeMemoryPressure:     v1.NodeMemoryPressure,
 		algorithm.TaintNodeOutOfDisk:          v1.NodeOutOfDisk,
@@ -454,10 +449,10 @@ func (nc *Controller) doNoScheduleTaintingPass(node *v1.Node) error {
 	// Map node's condition to Taints.
 	var taints []v1.Taint
 	for _, condition := range node.Status.Conditions {
-		if taint, found := nodeConditionToTaintKeyStatusMap[condition.Type]; found {
-			if condition.Status == taint.noScheduleStatus {
+		if taintMap, found := nodeConditionToTaintKeyStatusMap[condition.Type]; found {
+			if taintKey, found := taintMap[condition.Status]; found {
 				taints = append(taints, v1.Taint{
-					Key:    taint.taintKey,
+					Key:    taintKey,
 					Effect: v1.TaintEffectNoSchedule,
 				})
 			}
@@ -473,6 +468,10 @@ func (nc *Controller) doNoScheduleTaintingPass(node *v1.Node) error {
 
 	// Get exist taints of node.
 	nodeTaints := taintutils.TaintSetFilter(node.Spec.Taints, func(t *v1.Taint) bool {
+		// only NoSchedule taints are candidates to be compared with "taints" later
+		if t.Effect != v1.TaintEffectNoSchedule {
+			return false
+		}
 		// Find unschedulable taint of node.
 		if t.Key == algorithm.TaintNodeUnschedulable {
 			return true

pkg/controller/nodelifecycle/node_lifecycle_controller_test.go

@@ -2167,6 +2167,10 @@ func TestTaintsNodeByCondition(t *testing.T) {
 		Key:    algorithm.TaintNodeNotReady,
 		Effect: v1.TaintEffectNoSchedule,
 	}
+	unreachableTaint := &v1.Taint{
+		Key:    algorithm.TaintNodeUnreachable,
+		Effect: v1.TaintEffectNoSchedule,
+	}
 
 	tests := []struct {
 		Name           string
@@ -2299,6 +2303,30 @@ func TestTaintsNodeByCondition(t *testing.T) {
 			},
 			ExpectedTaints: []*v1.Taint{notReadyTaint},
 		},
+		{
+			Name: "Ready is unknown",
+			Node: &v1.Node{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:              "node0",
+					CreationTimestamp: metav1.Date(2012, 1, 1, 0, 0, 0, 0, time.UTC),
+					Labels: map[string]string{
+						kubeletapis.LabelZoneRegion:        "region1",
+						kubeletapis.LabelZoneFailureDomain: "zone1",
+					},
+				},
+				Status: v1.NodeStatus{
+					Conditions: []v1.NodeCondition{
+						{
+							Type:               v1.NodeReady,
+							Status:             v1.ConditionUnknown,
+							LastHeartbeatTime:  metav1.Date(2015, 1, 1, 12, 0, 0, 0, time.UTC),
+							LastTransitionTime: metav1.Date(2015, 1, 1, 12, 0, 0, 0, time.UTC),
+						},
+					},
+				},
+			},
+			ExpectedTaints: []*v1.Taint{unreachableTaint},
+		},
 	}
 
 	for _, test := range tests {