Keep backward compatibility for 'node.Spec.Unschedulable'.

Signed-off-by: Da K. Ma <klaus1982.cn@gmail.com>

pkg/scheduler/algorithm/predicates/predicates.go

@@ -1470,7 +1470,14 @@ func CheckNodeUnschedulablePredicate(pod *v1.Pod, meta algorithm.PredicateMetada
 		return false, []algorithm.PredicateFailureReason{ErrNodeUnknownCondition}, nil
 	}
 
-	if nodeInfo.Node().Spec.Unschedulable {
+	// If pod tolerate unschedulable taint, it's also tolerate `node.Spec.Unschedulable`.
+	podToleratesUnschedulable := v1helper.TolerationsTolerateTaint(pod.Spec.Tolerations, &v1.Taint{
+		Key:    algorithm.TaintNodeUnschedulable,
+		Effect: v1.TaintEffectNoSchedule,
+	})
+
+	// TODO (k82cn): deprecates `node.Spec.Unschedulable` in 1.13.
+	if nodeInfo.Node().Spec.Unschedulable && !podToleratesUnschedulable {
 		return false, []algorithm.PredicateFailureReason{ErrNodeUnschedulable}, nil
 	}
 

pkg/scheduler/algorithm/predicates/predicates_test.go

@@ -4982,3 +4982,65 @@ func TestGetMaxVols(t *testing.T) {
 		os.Setenv(KubeMaxPDVols, previousValue)
 	}
 }
+
+func TestCheckNodeUnschedulablePredicate(t *testing.T) {
+	testCases := []struct {
+		name string
+		pod  *v1.Pod
+		node *v1.Node
+		fit  bool
+	}{
+		{
+			name: "Does not schedule pod to unschedulable node (node.Spec.Unschedulable==true)",
+			pod:  &v1.Pod{},
+			node: &v1.Node{
+				Spec: v1.NodeSpec{
+					Unschedulable: true,
+				},
+			},
+			fit: false,
+		},
+		{
+			name: "Schedule pod to normal node",
+			pod:  &v1.Pod{},
+			node: &v1.Node{
+				Spec: v1.NodeSpec{
+					Unschedulable: false,
+				},
+			},
+			fit: true,
+		},
+		{
+			name: "Schedule pod with toleration to unschedulable node (node.Spec.Unschedulable==true)",
+			pod: &v1.Pod{
+				Spec: v1.PodSpec{
+					Tolerations: []v1.Toleration{
+						{
+							Key:    algorithm.TaintNodeUnschedulable,
+							Effect: v1.TaintEffectNoSchedule,
+						},
+					},
+				},
+			},
+			node: &v1.Node{
+				Spec: v1.NodeSpec{
+					Unschedulable: true,
+				},
+			},
+			fit: true,
+		},
+	}
+
+	for _, test := range testCases {
+		nodeInfo := schedulercache.NewNodeInfo()
+		nodeInfo.SetNode(test.node)
+		fit, _, err := CheckNodeUnschedulablePredicate(test.pod, nil, nodeInfo)
+		if err != nil {
+			t.Fatalf("Failed to check node unschedulable: %v", err)
+		}
+
+		if fit != test.fit {
+			t.Errorf("Unexpected fit: expected %v, got %v", test.fit, fit)
+		}
+	}
+}

pkg/scheduler/algorithmprovider/defaults/defaults.go

@@ -199,10 +199,13 @@ func ApplyFeatureGates() {
 
 		// Fit is determined based on whether a pod can tolerate all of the node's taints
 		factory.RegisterMandatoryFitPredicate(predicates.PodToleratesNodeTaintsPred, predicates.PodToleratesNodeTaints)
+		// Fit is determined based on whether a pod can tolerate unschedulable of node
+		factory.RegisterMandatoryFitPredicate(predicates.CheckNodeUnschedulablePred, predicates.CheckNodeUnschedulablePredicate)
 		// Insert Key "PodToleratesNodeTaints" and "CheckNodeUnschedulable" To All Algorithm Provider
 		// The key will insert to all providers which in algorithmProviderMap[]
 		// if you just want insert to specific provider, call func InsertPredicateKeyToAlgoProvider()
 		factory.InsertPredicateKeyToAlgorithmProviderMap(predicates.PodToleratesNodeTaintsPred)
+		factory.InsertPredicateKeyToAlgorithmProviderMap(predicates.CheckNodeUnschedulablePred)
 
 		glog.Warningf("TaintNodesByCondition is enabled, PodToleratesNodeTaints predicate is mandatory")
 	}