Add support for rescheduled pods with the same name in drain

cluster-autoscaler/core/scale_down.go

@@ -762,14 +762,15 @@ func drainNode(node *apiv1.Node, pods []*apiv1.Pod, client kube_client.Interface
 		allGone = true
 		for _, pod := range pods {
 			podreturned, err := client.CoreV1().Pods(pod.Namespace).Get(pod.Name, metav1.GetOptions{})
-			if err == nil {
+			if err == nil && (podreturned == nil || podreturned.Spec.NodeName == node.Name) {
 				glog.Errorf("Not deleted yet %v", podreturned)
 				allGone = false
 				break
 			}
-			if !kube_errors.IsNotFound(err) {
+			if err != nil && !kube_errors.IsNotFound(err) {
 				glog.Errorf("Failed to check pod %s/%s: %v", pod.Namespace, pod.Name, err)
 				allGone = false
+				break
 			}
 		}
 		if allGone {

cluster-autoscaler/core/scale_down_test.go

@@ -635,6 +635,49 @@ func TestDrainNode(t *testing.T) {
 	assert.Equal(t, p2.Name, deleted[1])
 }
 
+func TestDrainNodeWithRescheduled(t *testing.T) {
+	deletedPods := make(chan string, 10)
+	fakeClient := &fake.Clientset{}
+
+	p1 := BuildTestPod("p1", 100, 0)
+	p2 := BuildTestPod("p2", 300, 0)
+	p2Rescheduled := BuildTestPod("p2", 300, 0)
+	p2Rescheduled.Spec.NodeName = "n2"
+	n1 := BuildTestNode("n1", 1000, 1000)
+	SetNodeReadyState(n1, true, time.Time{})
+
+	fakeClient.Fake.AddReactor("get", "pods", func(action core.Action) (bool, runtime.Object, error) {
+		getAction := action.(core.GetAction)
+		if getAction == nil {
+			return false, nil, nil
+		}
+		if getAction.GetName() == "p2" {
+			return true, p2Rescheduled, nil
+		}
+		return true, nil, errors.NewNotFound(apiv1.Resource("pod"), "whatever")
+	})
+	fakeClient.Fake.AddReactor("create", "pods", func(action core.Action) (bool, runtime.Object, error) {
+		createAction := action.(core.CreateAction)
+		if createAction == nil {
+			return false, nil, nil
+		}
+		eviction := createAction.GetObject().(*policyv1.Eviction)
+		if eviction == nil {
+			return false, nil, nil
+		}
+		deletedPods <- eviction.Name
+		return true, nil, nil
+	})
+	err := drainNode(n1, []*apiv1.Pod{p1, p2}, fakeClient, kube_util.CreateEventRecorder(fakeClient), 20, 5*time.Second, 0*time.Second)
+	assert.NoError(t, err)
+	deleted := make([]string, 0)
+	deleted = append(deleted, getStringFromChan(deletedPods))
+	deleted = append(deleted, getStringFromChan(deletedPods))
+	sort.Strings(deleted)
+	assert.Equal(t, p1.Name, deleted[0])
+	assert.Equal(t, p2.Name, deleted[1])
+}
+
 func TestDrainNodeWithRetries(t *testing.T) {
 	deletedPods := make(chan string, 10)
 	// Simulate pdb of size 1, by making them goroutine succeed sequentially