From d33494d459020e0089ff3ae5b9d142d8b6cede9e Mon Sep 17 00:00:00 2001 From: mattjmcnaughton Date: Wed, 7 Mar 2018 08:57:11 -0500 Subject: [PATCH] `GetExternalMetricReplicas` ignores unready pods Similar to the change we made for `GetObjectMetricReplicas` in the previous commit. Ensure that `GetExternalMetricReplicas` does not include unready pods when its determining how many replica it desires. Including unready pods can lead to over-scaling. We did not change the behavior of `GetExternalPerPodMetricReplicas`, as it is slightly less clear what is the desired behavior. We did make some small naming refactorings to this method, which will make it easier to ignore unready pods if we decide we want to. --- pkg/controller/podautoscaler/horizontal.go | 2 +- .../podautoscaler/replica_calculator.go | 33 ++++++++++--------- .../podautoscaler/replica_calculator_test.go | 20 +++++++++-- 3 files changed, 36 insertions(+), 19 deletions(-) diff --git a/pkg/controller/podautoscaler/horizontal.go b/pkg/controller/podautoscaler/horizontal.go index c25d6b81883..c566d773203 100644 --- a/pkg/controller/podautoscaler/horizontal.go +++ b/pkg/controller/podautoscaler/horizontal.go @@ -317,7 +317,7 @@ func (a *HorizontalController) computeReplicasForMetrics(hpa *autoscalingv2.Hori }, } } else if metricSpec.External.TargetValue != nil { - replicaCountProposal, utilizationProposal, timestampProposal, err = a.replicaCalc.GetExternalMetricReplicas(currentReplicas, metricSpec.External.TargetValue.MilliValue(), metricSpec.External.MetricName, hpa.Namespace, metricSpec.External.MetricSelector) + replicaCountProposal, utilizationProposal, timestampProposal, err = a.replicaCalc.GetExternalMetricReplicas(currentReplicas, metricSpec.External.TargetValue.MilliValue(), metricSpec.External.MetricName, hpa.Namespace, metricSpec.External.MetricSelector, selector) if err != nil { a.eventRecorder.Event(hpa, v1.EventTypeWarning, "FailedGetExternalMetric", err.Error()) setCondition(hpa, autoscalingv2.ScalingActive, v1.ConditionFalse, "FailedGetExternalMetric", "the HPA was unable to compute the replica count: %v", err) diff --git a/pkg/controller/podautoscaler/replica_calculator.go b/pkg/controller/podautoscaler/replica_calculator.go index 2dd22c6c065..7dc26f9a738 100644 --- a/pkg/controller/podautoscaler/replica_calculator.go +++ b/pkg/controller/podautoscaler/replica_calculator.go @@ -288,9 +288,6 @@ func (c *ReplicaCalculator) GetObjectMetricReplicas(currentReplicas int32, targe return currentReplicas, utilization, timestamp, nil } - // Calculate the total number of ready pods, as we want to base the - // replica count off of how many pods are ready, not how many pods - // exist. readyPodCount, err := c.getReadyPodsCount(namespace, selector) if err != nil { @@ -318,11 +315,9 @@ func (c *ReplicaCalculator) getReadyPodsCount(namespace string, selector labels. readyPodCount := 0 for _, pod := range podList.Items { - if pod.Status.Phase != v1.PodRunning || !podutil.IsPodReady(&pod) { - continue + if pod.Status.Phase == v1.PodRunning && podutil.IsPodReady(&pod) { + readyPodCount++ } - - readyPodCount++ } return int64(readyPodCount), nil @@ -331,40 +326,46 @@ func (c *ReplicaCalculator) getReadyPodsCount(namespace string, selector labels. // GetExternalMetricReplicas calculates the desired replica count based on a // target metric value (as a milli-value) for the external metric in the given // namespace, and the current replica count. -func (c *ReplicaCalculator) GetExternalMetricReplicas(currentReplicas int32, targetUtilization int64, metricName, namespace string, selector *metav1.LabelSelector) (replicaCount int32, utilization int64, timestamp time.Time, err error) { - labelSelector, err := metav1.LabelSelectorAsSelector(selector) +func (c *ReplicaCalculator) GetExternalMetricReplicas(currentReplicas int32, targetUtilization int64, metricName, namespace string, metricSelector *metav1.LabelSelector, podSelector labels.Selector) (replicaCount int32, utilization int64, timestamp time.Time, err error) { + metricLabelSelector, err := metav1.LabelSelectorAsSelector(metricSelector) if err != nil { return 0, 0, time.Time{}, err } - metrics, timestamp, err := c.metricsClient.GetExternalMetric(metricName, namespace, labelSelector) + metrics, timestamp, err := c.metricsClient.GetExternalMetric(metricName, namespace, metricLabelSelector) if err != nil { - return 0, 0, time.Time{}, fmt.Errorf("unable to get external metric %s/%s/%+v: %s", namespace, metricName, selector, err) + return 0, 0, time.Time{}, fmt.Errorf("unable to get external metric %s/%s/%+v: %s", namespace, metricName, metricSelector, err) } utilization = 0 for _, val := range metrics { utilization = utilization + val } + readyPodCount, err := c.getReadyPodsCount(namespace, podSelector) + + if err != nil { + return 0, 0, time.Time{}, fmt.Errorf("unable to calculate ready pods: %s", err) + } + usageRatio := float64(utilization) / float64(targetUtilization) if math.Abs(1.0-usageRatio) <= c.tolerance { // return the current replicas if the change would be too small return currentReplicas, utilization, timestamp, nil } - return int32(math.Ceil(usageRatio * float64(currentReplicas))), utilization, timestamp, nil + return int32(math.Ceil(usageRatio * float64(readyPodCount))), utilization, timestamp, nil } // GetExternalPerPodMetricReplicas calculates the desired replica count based on a // target metric value per pod (as a milli-value) for the external metric in the // given namespace, and the current replica count. -func (c *ReplicaCalculator) GetExternalPerPodMetricReplicas(currentReplicas int32, targetUtilizationPerPod int64, metricName, namespace string, selector *metav1.LabelSelector) (replicaCount int32, utilization int64, timestamp time.Time, err error) { - labelSelector, err := metav1.LabelSelectorAsSelector(selector) +func (c *ReplicaCalculator) GetExternalPerPodMetricReplicas(currentReplicas int32, targetUtilizationPerPod int64, metricName, namespace string, metricSelector *metav1.LabelSelector) (replicaCount int32, utilization int64, timestamp time.Time, err error) { + metricLabelSelector, err := metav1.LabelSelectorAsSelector(metricSelector) if err != nil { return 0, 0, time.Time{}, err } - metrics, timestamp, err := c.metricsClient.GetExternalMetric(metricName, namespace, labelSelector) + metrics, timestamp, err := c.metricsClient.GetExternalMetric(metricName, namespace, metricLabelSelector) if err != nil { - return 0, 0, time.Time{}, fmt.Errorf("unable to get external metric %s/%s/%+v: %s", namespace, metricName, selector, err) + return 0, 0, time.Time{}, fmt.Errorf("unable to get external metric %s/%s/%+v: %s", namespace, metricName, metricSelector, err) } utilization = 0 for _, val := range metrics { diff --git a/pkg/controller/podautoscaler/replica_calculator_test.go b/pkg/controller/podautoscaler/replica_calculator_test.go index 042eae2ab8e..b67bcc4710b 100644 --- a/pkg/controller/podautoscaler/replica_calculator_test.go +++ b/pkg/controller/podautoscaler/replica_calculator_test.go @@ -326,7 +326,7 @@ func (tc *replicaCalcTestCase) runTest(t *testing.T) { outReplicas, outUtilization, outTimestamp, err = replicaCalc.GetObjectMetricReplicas(tc.currentReplicas, tc.metric.targetUtilization, tc.metric.name, testNamespace, tc.metric.singleObject, selector) } else if tc.metric.selector != nil { if tc.metric.targetUtilization > 0 { - outReplicas, outUtilization, outTimestamp, err = replicaCalc.GetExternalMetricReplicas(tc.currentReplicas, tc.metric.targetUtilization, tc.metric.name, testNamespace, tc.metric.selector) + outReplicas, outUtilization, outTimestamp, err = replicaCalc.GetExternalMetricReplicas(tc.currentReplicas, tc.metric.targetUtilization, tc.metric.name, testNamespace, tc.metric.selector, selector) } else if tc.metric.perPodTargetUtilization > 0 { outReplicas, outUtilization, outTimestamp, err = replicaCalc.GetExternalPerPodMetricReplicas(tc.currentReplicas, tc.metric.perPodTargetUtilization, tc.metric.name, testNamespace, tc.metric.selector) } @@ -497,7 +497,7 @@ func TestReplicaCalcScaleUpCMObject(t *testing.T) { tc.runTest(t) } -func TestReplicaCalcScaleUpCMObjectIgnoreUnreadyPods(t *testing.T) { +func TestReplicaCalcScaleUpCMObjectIgnoresUnreadyPods(t *testing.T) { tc := replicaCalcTestCase{ currentReplicas: 3, expectedReplicas: 5, // If we did not ignore unready pods, we'd expect 15 replicas. @@ -532,6 +532,22 @@ func TestReplicaCalcScaleUpCMExternal(t *testing.T) { tc.runTest(t) } +func TestReplicaCalcScaleUpCMExternalIgnoresUnreadyPods(t *testing.T) { + tc := replicaCalcTestCase{ + currentReplicas: 3, + expectedReplicas: 2, // Would expect 6 if we didn't ignore unready pods + podReadiness: []v1.ConditionStatus{v1.ConditionFalse, v1.ConditionTrue, v1.ConditionFalse}, + metric: &metricInfo{ + name: "qps", + levels: []int64{8600}, + targetUtilization: 4400, + expectedUtilization: 8600, + selector: &metav1.LabelSelector{MatchLabels: map[string]string{"label": "value"}}, + }, + } + tc.runTest(t) +} + func TestReplicaCalcScaleUpCMExternalNoLabels(t *testing.T) { tc := replicaCalcTestCase{ currentReplicas: 1,