Add e2e test for HPA behavior: decreased downscale stabilization

test/e2e/autoscaling/horizontal_pod_autoscaling_behavior.go

@@ -0,0 +1,84 @@
+/*
+Copyright 2015 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package autoscaling
+
+import (
+	"time"
+
+	"k8s.io/kubernetes/test/e2e/framework"
+	e2eautoscaling "k8s.io/kubernetes/test/e2e/framework/autoscaling"
+
+	"github.com/onsi/ginkgo"
+)
+
+var _ = SIGDescribe("[Feature:HPA] [Serial] [Slow] Horizontal pod autoscaling (non-default behavior)", func() {
+	f := framework.NewDefaultFramework("horizontal-pod-autoscaling")
+
+	ginkgo.Describe("with low downscale stabilization window", func() {
+		ginkgo.It("should scale down soon after the stabilization period", func() {
+			ginkgo.By("setting up resource consumer and HPA")
+			podCPURequest := 500
+			targetCPUUtilizationPercent := 25
+			usageForSingleReplica := 110
+			initPods := 1
+			initCPUUsageTotal := initPods * usageForSingleReplica
+			downScaleStabilization := 1 * time.Minute
+
+			rc := e2eautoscaling.NewDynamicResourceConsumer(
+				"consumer", f.Namespace.Name, e2eautoscaling.KindDeployment, initPods,
+				initCPUUsageTotal, 0, 0, int64(podCPURequest), 200,
+				f.ClientSet, f.ScalesGetter, e2eautoscaling.Disable, e2eautoscaling.Idle,
+			)
+			defer rc.CleanUp()
+
+			hpa := e2eautoscaling.CreateCPUHorizontalPodAutoscalerWithBehavior(
+				rc, int32(targetCPUUtilizationPercent), 1, 5, int32(downScaleStabilization.Seconds()),
+			)
+			defer e2eautoscaling.DeleteHPAWithBehavior(rc, hpa.Name)
+
+			// 30s of metrics window and
+			// up to 30s until the old metrics window finishes
+			// and additional 15s until metrics available on a new pod
+			metricsAvailableDelay := 75 * time.Second
+			hpaReconciliationInterval := 15 * time.Second
+			actuationDelay := 10 * time.Second
+			maxHPAReactionTime := metricsAvailableDelay + hpaReconciliationInterval + actuationDelay
+
+			maxConsumeCPUDelay := 30 * time.Second
+			waitForReplicasPollInterval := 20 * time.Second
+			maxResourceConsumerDelay := maxConsumeCPUDelay + waitForReplicasPollInterval
+
+			waitBuffer := 1 * time.Minute
+
+			ginkgo.By("triggering scale up to record a recommendation")
+			rc.ConsumeCPU(3 * usageForSingleReplica)
+			rc.WaitForReplicas(3, maxHPAReactionTime+maxResourceConsumerDelay+waitBuffer)
+
+			ginkgo.By("triggering scale down by lowering consumption")
+			rc.ConsumeCPU(2 * usageForSingleReplica)
+			waitStart := time.Now()
+			rc.WaitForReplicas(2, downScaleStabilization+maxHPAReactionTime+maxResourceConsumerDelay+waitBuffer)
+			timeWaited := time.Now().Sub(waitStart)
+
+			ginkgo.By("verifying time waited for a scale down")
+			framework.Logf("time waited for scale down: %s", timeWaited)
+			framework.ExpectEqual(timeWaited > downScaleStabilization, true, "waited %s, wanted more than %s", timeWaited, downScaleStabilization)
+			deadline := downScaleStabilization + maxHPAReactionTime + maxResourceConsumerDelay
+			framework.ExpectEqual(timeWaited < deadline, true, "waited %s, wanted less than %s", timeWaited, deadline)
+		})
+	})
+})

test/e2e/framework/autoscaling/autoscaling_utils.go

@@ -667,6 +667,48 @@ func DeleteContainerResourceHPA(rc *ResourceConsumer, autoscalerName string) {
 	rc.clientSet.AutoscalingV2().HorizontalPodAutoscalers(rc.nsName).Delete(context.TODO(), autoscalerName, metav1.DeleteOptions{})
 }
 
+func CreateCPUHorizontalPodAutoscalerWithBehavior(rc *ResourceConsumer, cpu, minReplicas, maxRepl, downscaleStabilizationSeconds int32) *autoscalingv2.HorizontalPodAutoscaler {
+	hpa := &autoscalingv2.HorizontalPodAutoscaler{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      rc.name,
+			Namespace: rc.nsName,
+		},
+		Spec: autoscalingv2.HorizontalPodAutoscalerSpec{
+			ScaleTargetRef: autoscalingv2.CrossVersionObjectReference{
+				APIVersion: rc.kind.GroupVersion().String(),
+				Kind:       rc.kind.Kind,
+				Name:       rc.name,
+			},
+			MinReplicas: &minReplicas,
+			MaxReplicas: maxRepl,
+			Metrics: []autoscalingv2.MetricSpec{
+				{
+					Type: autoscalingv2.ResourceMetricSourceType,
+					Resource: &autoscalingv2.ResourceMetricSource{
+						Name: v1.ResourceCPU,
+						Target: autoscalingv2.MetricTarget{
+							Type:               autoscalingv2.UtilizationMetricType,
+							AverageUtilization: &cpu,
+						},
+					},
+				},
+			},
+			Behavior: &autoscalingv2.HorizontalPodAutoscalerBehavior{
+				ScaleDown: &autoscalingv2.HPAScalingRules{
+					StabilizationWindowSeconds: &downscaleStabilizationSeconds,
+				},
+			},
+		},
+	}
+	hpa, errHPA := rc.clientSet.AutoscalingV2().HorizontalPodAutoscalers(rc.nsName).Create(context.TODO(), hpa, metav1.CreateOptions{})
+	framework.ExpectNoError(errHPA)
+	return hpa
+}
+
+func DeleteHPAWithBehavior(rc *ResourceConsumer, autoscalerName string) {
+	rc.clientSet.AutoscalingV2().HorizontalPodAutoscalers(rc.nsName).Delete(context.TODO(), autoscalerName, metav1.DeleteOptions{})
+}
+
 //SidecarStatusType type for sidecar status
 type SidecarStatusType bool