Add request processing HPA into the queue after processing is finished.

pkg/controller/podautoscaler/horizontal.go

@@ -207,14 +207,18 @@ func (a *HorizontalController) processNextWorkItem() bool {
 	}
 	defer a.queue.Done(key)
 
-	err := a.reconcileKey(key.(string))
-	if err == nil {
-		// don't "forget" here because we want to only process a given HPA once per resync interval
-		return true
+	deleted, err := a.reconcileKey(key.(string))
+	if err != nil {
+		utilruntime.HandleError(err)
+	}
+	// Add request processing HPA after resync interval just in case last resync didn't insert
+	// request into the queue. Request is not inserted into queue by resync if previous one wasn't processed yet.
+	// This happens quite often because requests from previous resync are removed from the queue at the same moment
+	// as next resync inserts new requests.
+	if !deleted {
+		a.queue.AddRateLimited(key)
 	}
 
-	a.queue.AddRateLimited(key)
-	utilruntime.HandleError(err)
 	return true
 }
 
@@ -298,20 +302,20 @@ func (a *HorizontalController) computeReplicasForMetrics(hpa *autoscalingv2.Hori
 	return replicas, metric, statuses, timestamp, nil
 }
 
-func (a *HorizontalController) reconcileKey(key string) error {
+func (a *HorizontalController) reconcileKey(key string) (deleted bool, err error) {
 	namespace, name, err := cache.SplitMetaNamespaceKey(key)
 	if err != nil {
-		return err
+		return true, err
 	}
 
 	hpa, err := a.hpaLister.HorizontalPodAutoscalers(namespace).Get(name)
 	if errors.IsNotFound(err) {
 		klog.Infof("Horizontal Pod Autoscaler %s has been deleted in %s", name, namespace)
 		delete(a.recommendations, key)
-		return nil
+		return true, nil
 	}
 
-	return a.reconcileAutoscaler(hpa, key)
+	return false, a.reconcileAutoscaler(hpa, key)
 }
 
 // computeStatusForObjectMetric computes the desired number of replicas for the specified metric of type ObjectMetricSourceType.

pkg/controller/podautoscaler/horizontal_test.go

@@ -2176,7 +2176,7 @@ func TestComputedToleranceAlgImplementation(t *testing.T) {
 	finalPods := int32(math.Ceil(resourcesUsedRatio * float64(startPods)))
 
 	// To breach tolerance we will create a utilization ratio difference of tolerance to usageRatioToleranceValue)
-	tc := testCase{
+	tc1 := testCase{
 		minReplicas:             0,
 		maxReplicas:             1000,
 		initialReplicas:         startPods,
@@ -2209,22 +2209,49 @@ func TestComputedToleranceAlgImplementation(t *testing.T) {
 		useMetricsAPI:   true,
 		recommendations: []timestampedRecommendation{},
 	}
+	tc1.runTest(t)
 
-	tc.runTest(t)
-
-	// Reuse the data structure above, now testing "unscaling".
-	// Now, we test that no scaling happens if we are in a very close margin to the tolerance
 	target = math.Abs(1/(requestedToUsed*(1-defaultTestingTolerance))) + .004
 	finalCPUPercentTarget = int32(target * 100)
-	tc.CPUTarget = finalCPUPercentTarget
-	tc.initialReplicas = startPods
-	tc.expectedDesiredReplicas = startPods
-	tc.expectedConditions = statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
-		Type:   autoscalingv2.AbleToScale,
-		Status: v1.ConditionTrue,
-		Reason: "ReadyForNewScale",
-	})
-	tc.runTest(t)
+	tc2 := testCase{
+		minReplicas:             0,
+		maxReplicas:             1000,
+		initialReplicas:         startPods,
+		expectedDesiredReplicas: startPods,
+		CPUTarget:               finalCPUPercentTarget,
+		reportedLevels: []uint64{
+			totalUsedCPUOfAllPods / 10,
+			totalUsedCPUOfAllPods / 10,
+			totalUsedCPUOfAllPods / 10,
+			totalUsedCPUOfAllPods / 10,
+			totalUsedCPUOfAllPods / 10,
+			totalUsedCPUOfAllPods / 10,
+			totalUsedCPUOfAllPods / 10,
+			totalUsedCPUOfAllPods / 10,
+			totalUsedCPUOfAllPods / 10,
+			totalUsedCPUOfAllPods / 10,
+		},
+		reportedCPURequests: []resource.Quantity{
+			resource.MustParse(fmt.Sprint(perPodRequested+100) + "m"),
+			resource.MustParse(fmt.Sprint(perPodRequested-100) + "m"),
+			resource.MustParse(fmt.Sprint(perPodRequested+10) + "m"),
+			resource.MustParse(fmt.Sprint(perPodRequested-10) + "m"),
+			resource.MustParse(fmt.Sprint(perPodRequested+2) + "m"),
+			resource.MustParse(fmt.Sprint(perPodRequested-2) + "m"),
+			resource.MustParse(fmt.Sprint(perPodRequested+1) + "m"),
+			resource.MustParse(fmt.Sprint(perPodRequested-1) + "m"),
+			resource.MustParse(fmt.Sprint(perPodRequested) + "m"),
+			resource.MustParse(fmt.Sprint(perPodRequested) + "m"),
+		},
+		useMetricsAPI:   true,
+		recommendations: []timestampedRecommendation{},
+		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
+			Type:   autoscalingv2.AbleToScale,
+			Status: v1.ConditionTrue,
+			Reason: "ReadyForNewScale",
+		}),
+	}
+	tc2.runTest(t)
 }
 
 func TestScaleUpRCImmediately(t *testing.T) {

pkg/controller/podautoscaler/legacy_horizontal_test.go

@@ -100,6 +100,8 @@ type legacyTestCase struct {
 	// Last scale time
 	lastScaleTime   *metav1.Time
 	recommendations []timestampedRecommendation
+
+	finished bool
 }
 
 // Needs to be called under a lock.
@@ -462,12 +464,14 @@ func (tc *legacyTestCase) verifyResults(t *testing.T) {
 func (tc *legacyTestCase) runTest(t *testing.T) {
 	testClient, testScaleClient := tc.prepareTestClient(t)
 	metricsClient := metrics.NewHeapsterMetricsClient(testClient, metrics.DefaultHeapsterNamespace, metrics.DefaultHeapsterScheme, metrics.DefaultHeapsterService, metrics.DefaultHeapsterPort)
-
 	eventClient := &fake.Clientset{}
 	eventClient.AddReactor("*", "events", func(action core.Action) (handled bool, ret runtime.Object, err error) {
 		tc.Lock()
 		defer tc.Unlock()
 
+		if tc.finished {
+			return true, &v1.Event{}, nil
+		}
 		obj := action.(core.CreateAction).GetObject().(*v1.Event)
 		if tc.verifyEvents {
 			switch obj.Reason {
@@ -514,17 +518,19 @@ func (tc *legacyTestCase) runTest(t *testing.T) {
 	informerFactory.Start(stop)
 	go hpaController.Run(stop)
 
+	// Wait for HPA to be processed.
+	<-tc.processed
 	tc.Lock()
+	tc.finished = true
 	if tc.verifyEvents {
 		tc.Unlock()
 		// We need to wait for events to be broadcasted (sleep for longer than record.sleepDuration).
 		time.Sleep(2 * time.Second)
 	} else {
 		tc.Unlock()
 	}
-	// Wait for HPA to be processed.
-	<-tc.processed
 	tc.verifyResults(t)
+
 }
 
 func TestLegacyScaleUp(t *testing.T) {