Implement external metrics in HPA

pkg/controller/podautoscaler/BUILD

@@ -82,6 +82,7 @@ go_test(
         "//vendor/k8s.io/client-go/testing:go_default_library",
         "//vendor/k8s.io/heapster/metrics/api/v1/types:go_default_library",
         "//vendor/k8s.io/metrics/pkg/apis/custom_metrics/v1beta1:go_default_library",
+        "//vendor/k8s.io/metrics/pkg/apis/external_metrics/v1beta1:go_default_library",
         "//vendor/k8s.io/metrics/pkg/apis/metrics/v1alpha1:go_default_library",
         "//vendor/k8s.io/metrics/pkg/apis/metrics/v1beta1:go_default_library",
         "//vendor/k8s.io/metrics/pkg/client/clientset_generated/clientset/fake:go_default_library",

pkg/controller/podautoscaler/horizontal.go

@@ -299,6 +299,45 @@ func (a *HorizontalController) computeReplicasForMetrics(hpa *autoscalingv2.Hori
 					},
 				}
 			}
+		case autoscalingv2.ExternalMetricSourceType:
+			if metricSpec.External.TargetAverageValue != nil {
+				replicaCountProposal, utilizationProposal, timestampProposal, err = a.replicaCalc.GetExternalPerPodMetricReplicas(currentReplicas, metricSpec.External.TargetAverageValue.MilliValue(), metricSpec.External.MetricName, hpa.Namespace, metricSpec.External.MetricSelector)
+				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)
+					return 0, "", nil, time.Time{}, fmt.Errorf("failed to get %s external metric: %v", metricSpec.External.MetricName, err)
+				}
+				metricNameProposal = fmt.Sprintf("external metric %s(%+v)", metricSpec.External.MetricName, metricSpec.External.MetricSelector)
+				statuses[i] = autoscalingv2.MetricStatus{
+					Type: autoscalingv2.ExternalMetricSourceType,
+					External: &autoscalingv2.ExternalMetricStatus{
+						MetricSelector:      metricSpec.External.MetricSelector,
+						MetricName:          metricSpec.External.MetricName,
+						CurrentAverageValue: resource.NewMilliQuantity(utilizationProposal, resource.DecimalSI),
+					},
+				}
+			} 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)
+				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)
+					return 0, "", nil, time.Time{}, fmt.Errorf("failed to get external metric %s: %v", metricSpec.External.MetricName, err)
+				}
+				metricNameProposal = fmt.Sprintf("external metric %s(%+v)", metricSpec.External.MetricName, metricSpec.External.MetricSelector)
+				statuses[i] = autoscalingv2.MetricStatus{
+					Type: autoscalingv2.ExternalMetricSourceType,
+					External: &autoscalingv2.ExternalMetricStatus{
+						MetricSelector: metricSpec.External.MetricSelector,
+						MetricName:     metricSpec.External.MetricName,
+						CurrentValue:   *resource.NewMilliQuantity(utilizationProposal, resource.DecimalSI),
+					},
+				}
+			} else {
+				errMsg := "invalid external metric source: neither a value target nor an average value target was set"
+				a.eventRecorder.Event(hpa, v1.EventTypeWarning, "FailedGetExternalMetric", errMsg)
+				setCondition(hpa, autoscalingv2.ScalingActive, v1.ConditionFalse, "FailedGetExternalMetric", "the HPA was unable to compute the replica count: %v", err)
+				return 0, "", nil, time.Time{}, fmt.Errorf(errMsg)
+			}
 		default:
 			errMsg := fmt.Sprintf("unknown metric source type %q", string(metricSpec.Type))
 			a.eventRecorder.Event(hpa, v1.EventTypeWarning, "InvalidMetricSourceType", errMsg)

pkg/controller/podautoscaler/horizontal_test.go

@@ -42,6 +42,7 @@ import (
 	"k8s.io/kubernetes/pkg/controller"
 	"k8s.io/kubernetes/pkg/controller/podautoscaler/metrics"
 	cmapi "k8s.io/metrics/pkg/apis/custom_metrics/v1beta1"
+	emapi "k8s.io/metrics/pkg/apis/external_metrics/v1beta1"
 	metricsapi "k8s.io/metrics/pkg/apis/metrics/v1beta1"
 	metricsfake "k8s.io/metrics/pkg/client/clientset_generated/clientset/fake"
 	cmfake "k8s.io/metrics/pkg/client/custom_metrics/fake"
@@ -526,6 +527,31 @@ func (tc *testCase) prepareTestClient(t *testing.T) (*fake.Clientset, *metricsfa
 
 	fakeEMClient := &emfake.FakeExternalMetricsClient{}
 
+	fakeEMClient.AddReactor("list", "*", func(action core.Action) (handled bool, ret runtime.Object, err error) {
+		tc.Lock()
+		defer tc.Unlock()
+
+		listAction, wasList := action.(core.ListAction)
+		if !wasList {
+			return true, nil, fmt.Errorf("expected a list action, got %v instead", action)
+		}
+
+		metrics := &emapi.ExternalMetricValueList{}
+
+		assert.Equal(t, "qps", listAction.GetResource().Resource, "the metric name requested should have been qps, as specified in the metric spec")
+
+		for _, level := range tc.reportedLevels {
+			metric := emapi.ExternalMetricValue{
+				Timestamp:  metav1.Time{Time: time.Now()},
+				MetricName: "qps",
+				Value:      *resource.NewMilliQuantity(int64(level), resource.DecimalSI),
+			}
+			metrics.Items = append(metrics.Items, metric)
+		}
+
+		return true, metrics, nil
+	})
+
 	return fakeClient, fakeMetricsClient, fakeCMClient, fakeEMClient, fakeScaleClient
 }
 
@@ -826,6 +852,48 @@ func TestScaleUpCMObject(t *testing.T) {
 	tc.runTest(t)
 }
 
+func TestScaleUpCMExternal(t *testing.T) {
+	tc := testCase{
+		minReplicas:     2,
+		maxReplicas:     6,
+		initialReplicas: 3,
+		desiredReplicas: 4,
+		metricsTarget: []autoscalingv2.MetricSpec{
+			{
+				Type: autoscalingv2.ExternalMetricSourceType,
+				External: &autoscalingv2.ExternalMetricSource{
+					MetricSelector: &metav1.LabelSelector{},
+					MetricName:     "qps",
+					TargetValue:    resource.NewMilliQuantity(6666, resource.DecimalSI),
+				},
+			},
+		},
+		reportedLevels: []uint64{8600},
+	}
+	tc.runTest(t)
+}
+
+func TestScaleUpPerPodCMExternal(t *testing.T) {
+	tc := testCase{
+		minReplicas:     2,
+		maxReplicas:     6,
+		initialReplicas: 3,
+		desiredReplicas: 4,
+		metricsTarget: []autoscalingv2.MetricSpec{
+			{
+				Type: autoscalingv2.ExternalMetricSourceType,
+				External: &autoscalingv2.ExternalMetricSource{
+					MetricSelector:     &metav1.LabelSelector{},
+					MetricName:         "qps",
+					TargetAverageValue: resource.NewMilliQuantity(2222, resource.DecimalSI),
+				},
+			},
+		},
+		reportedLevels: []uint64{8600},
+	}
+	tc.runTest(t)
+}
+
 func TestScaleDown(t *testing.T) {
 	tc := testCase{
 		minReplicas:         2,
@@ -890,6 +958,48 @@ func TestScaleDownCMObject(t *testing.T) {
 	tc.runTest(t)
 }
 
+func TestScaleDownCMExternal(t *testing.T) {
+	tc := testCase{
+		minReplicas:     2,
+		maxReplicas:     6,
+		initialReplicas: 5,
+		desiredReplicas: 3,
+		metricsTarget: []autoscalingv2.MetricSpec{
+			{
+				Type: autoscalingv2.ExternalMetricSourceType,
+				External: &autoscalingv2.ExternalMetricSource{
+					MetricSelector: &metav1.LabelSelector{},
+					MetricName:     "qps",
+					TargetValue:    resource.NewMilliQuantity(14400, resource.DecimalSI),
+				},
+			},
+		},
+		reportedLevels: []uint64{8600},
+	}
+	tc.runTest(t)
+}
+
+func TestScaleDownPerPodCMExternal(t *testing.T) {
+	tc := testCase{
+		minReplicas:     2,
+		maxReplicas:     6,
+		initialReplicas: 5,
+		desiredReplicas: 3,
+		metricsTarget: []autoscalingv2.MetricSpec{
+			{
+				Type: autoscalingv2.ExternalMetricSourceType,
+				External: &autoscalingv2.ExternalMetricSource{
+					MetricSelector:     &metav1.LabelSelector{},
+					MetricName:         "qps",
+					TargetAverageValue: resource.NewMilliQuantity(3000, resource.DecimalSI),
+				},
+			},
+		},
+		reportedLevels: []uint64{8600},
+	}
+	tc.runTest(t)
+}
+
 func TestScaleDownIgnoresUnreadyPods(t *testing.T) {
 	tc := testCase{
 		minReplicas:          2,
@@ -983,6 +1093,58 @@ func TestToleranceCMObject(t *testing.T) {
 	tc.runTest(t)
 }
 
+func TestToleranceCMExternal(t *testing.T) {
+	tc := testCase{
+		minReplicas:     2,
+		maxReplicas:     6,
+		initialReplicas: 4,
+		desiredReplicas: 4,
+		metricsTarget: []autoscalingv2.MetricSpec{
+			{
+				Type: autoscalingv2.ExternalMetricSourceType,
+				External: &autoscalingv2.ExternalMetricSource{
+					MetricSelector: &metav1.LabelSelector{},
+					MetricName:     "qps",
+					TargetValue:    resource.NewMilliQuantity(8666, resource.DecimalSI),
+				},
+			},
+		},
+		reportedLevels: []uint64{8600},
+		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
+			Type:   autoscalingv2.AbleToScale,
+			Status: v1.ConditionTrue,
+			Reason: "ReadyForNewScale",
+		}),
+	}
+	tc.runTest(t)
+}
+
+func TestTolerancePerPodCMExternal(t *testing.T) {
+	tc := testCase{
+		minReplicas:     2,
+		maxReplicas:     6,
+		initialReplicas: 4,
+		desiredReplicas: 4,
+		metricsTarget: []autoscalingv2.MetricSpec{
+			{
+				Type: autoscalingv2.ExternalMetricSourceType,
+				External: &autoscalingv2.ExternalMetricSource{
+					MetricSelector:     &metav1.LabelSelector{},
+					MetricName:         "qps",
+					TargetAverageValue: resource.NewMilliQuantity(2200, resource.DecimalSI),
+				},
+			},
+		},
+		reportedLevels: []uint64{8600},
+		expectedConditions: statusOkWithOverrides(autoscalingv2.HorizontalPodAutoscalerCondition{
+			Type:   autoscalingv2.AbleToScale,
+			Status: v1.ConditionTrue,
+			Reason: "ReadyForNewScale",
+		}),
+	}
+	tc.runTest(t)
+}
+
 func TestMinReplicas(t *testing.T) {
 	tc := testCase{
 		minReplicas:         2,
@@ -1272,7 +1434,7 @@ func TestConditionInvalidSelectorMissing(t *testing.T) {
 		},
 	}
 
-	_, _, _, _,testScaleClient := tc.prepareTestClient(t)
+	_, _, _, _, testScaleClient := tc.prepareTestClient(t)
 	tc.testScaleClient = testScaleClient
 
 	testScaleClient.PrependReactor("get", "replicationcontrollers", func(action core.Action) (handled bool, ret runtime.Object, err error) {

pkg/controller/podautoscaler/metrics/rest_metrics_client.go

@@ -152,7 +152,7 @@ type externalMetricsClient struct {
 // GetExternalMetric gets all the values of a given external metric
 // that match the specified selector.
 func (c *externalMetricsClient) GetExternalMetric(metricName, namespace string, selector labels.Selector) ([]int64, time.Time, error) {
-	metrics, err := c.client.NamespacedMetrics(namespace).Get(metricName, selector)
+	metrics, err := c.client.NamespacedMetrics(namespace).List(metricName, selector)
 	if err != nil {
 		return []int64{}, time.Time{}, fmt.Errorf("unable to fetch metrics from external metrics API: %v", err)
 	}

pkg/controller/podautoscaler/metrics/rest_metrics_client_test.go

@@ -107,10 +107,10 @@ func (tc *restClientTestCase) prepareTestClient(t *testing.T) (*metricsfake.Clie
 			return true, metrics, nil
 		})
 	} else if isExternal {
-		fakeEMClient.AddReactor("get", "externalmetrics", func(action core.Action) (handled bool, ret runtime.Object, err error) {
+		fakeEMClient.AddReactor("list", "*", func(action core.Action) (handled bool, ret runtime.Object, err error) {
-			getForAction := action.(emfake.GetForAction)
+			listAction := action.(core.ListAction)
-			assert.Equal(t, tc.metricName, getForAction.GetMetricName(), "the metric requested should have matched the one specified.")
+			assert.Equal(t, tc.metricName, listAction.GetResource().Resource, "the metric requested should have matched the one specified.")
-			assert.Equal(t, tc.metricLabelSelector, getForAction.GetMetricSelector(), "the metric selector should have matched the one specified")
+			assert.Equal(t, tc.metricLabelSelector, listAction.GetListRestrictions().Labels, "the metric selector should have matched the one specified")
 
 			metrics := emapi.ExternalMetricValueList{}
 			for _, metricPoint := range tc.reportedMetricPoints {
@@ -325,7 +325,7 @@ func TestRESTClientQpsEmptyMetrics(t *testing.T) {
 func TestRESTClientExternalEmptyMetrics(t *testing.T) {
 	tc := restClientTestCase{
 		metricName:           "external",
-		metricSelector:       &metav1.LabelSelector{},
+		metricSelector:       &metav1.LabelSelector{MatchLabels: map[string]string{"label": "value"}},
 		desiredError:         fmt.Errorf("no metrics returned from external metrics API"),
 		reportedMetricPoints: []metricPoint{},
 	}

pkg/controller/podautoscaler/replica_calculator.go

@@ -278,6 +278,33 @@ func (c *ReplicaCalculator) GetObjectMetricReplicas(currentReplicas int32, targe
 		return 0, 0, time.Time{}, fmt.Errorf("unable to get metric %s: %v on %s %s/%s", metricName, objectRef.Kind, namespace, objectRef.Name, 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
+	}
+	replicaCount = int32(math.Ceil(usageRatio * float64(currentReplicas)))
+
+	return replicaCount, utilization, timestamp, nil
+}
+
+// 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)
+	if err != nil {
+		return 0, 0, time.Time{}, err
+	}
+	metrics, timestamp, err := c.metricsClient.GetExternalMetric(metricName, namespace, labelSelector)
+	if err != nil {
+		return 0, 0, time.Time{}, fmt.Errorf("unable to get external metric %s/%s/%+v: %s", namespace, metricName, selector, err)
+	}
+	utilization = 0
+	for _, val := range metrics {
+		utilization = utilization + val
+	}
+
 	usageRatio := float64(utilization) / float64(targetUtilization)
 	if math.Abs(1.0-usageRatio) <= c.tolerance {
 		// return the current replicas if the change would be too small
@@ -286,3 +313,30 @@ func (c *ReplicaCalculator) GetObjectMetricReplicas(currentReplicas int32, targe
 
 	return int32(math.Ceil(usageRatio * float64(currentReplicas))), 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)
+	if err != nil {
+		return 0, 0, time.Time{}, err
+	}
+	metrics, timestamp, err := c.metricsClient.GetExternalMetric(metricName, namespace, labelSelector)
+	if err != nil {
+		return 0, 0, time.Time{}, fmt.Errorf("unable to get external metric %s/%s/%+v: %s", namespace, metricName, selector, err)
+	}
+	utilization = 0
+	for _, val := range metrics {
+		utilization = utilization + val
+	}
+
+	replicaCount = currentReplicas
+	usageRatio := float64(utilization) / (float64(targetUtilizationPerPod) * float64(replicaCount))
+	if math.Abs(1.0-usageRatio) > c.tolerance {
+		// update number of replicas if the change is large enough
+		replicaCount = int32(math.Ceil(float64(utilization) / float64(targetUtilizationPerPod)))
+	}
+	utilization = int64(math.Ceil(float64(utilization) / float64(currentReplicas)))
+	return replicaCount, utilization, timestamp, nil
+}

pkg/controller/podautoscaler/replica_calculator_test.go

@@ -33,6 +33,7 @@ import (
 	"k8s.io/kubernetes/pkg/api/legacyscheme"
 	"k8s.io/kubernetes/pkg/controller/podautoscaler/metrics"
 	cmapi "k8s.io/metrics/pkg/apis/custom_metrics/v1beta1"
+	emapi "k8s.io/metrics/pkg/apis/external_metrics/v1beta1"
 	metricsapi "k8s.io/metrics/pkg/apis/metrics/v1beta1"
 	metricsfake "k8s.io/metrics/pkg/client/clientset_generated/clientset/fake"
 	cmfake "k8s.io/metrics/pkg/client/custom_metrics/fake"
@@ -58,8 +59,10 @@ type metricInfo struct {
 	name         string
 	levels       []int64
 	singleObject *autoscalingv2.CrossVersionObjectReference
+	selector     *metav1.LabelSelector
 
 	targetUtilization       int64
+	perPodTargetUtilization int64
 	expectedUtilization     int64
 }
 
@@ -238,6 +241,37 @@ func (tc *replicaCalcTestCase) prepareTestClient(t *testing.T) (*fake.Clientset,
 	})
 
 	fakeEMClient := &emfake.FakeExternalMetricsClient{}
+	fakeEMClient.AddReactor("list", "*", func(action core.Action) (handled bool, ret runtime.Object, err error) {
+		listAction, wasList := action.(core.ListAction)
+		if !wasList {
+			return true, nil, fmt.Errorf("expected a list-for action, got %v instead", action)
+		}
+
+		if tc.metric == nil {
+			return true, nil, fmt.Errorf("no external metrics specified in test client")
+		}
+
+		assert.Equal(t, tc.metric.name, listAction.GetResource().Resource, "the metric requested should have matched the one specified")
+
+		selector, err := metav1.LabelSelectorAsSelector(tc.metric.selector)
+		if err != nil {
+			return true, nil, fmt.Errorf("failed to convert label selector specified in test client")
+		}
+		assert.Equal(t, selector, listAction.GetListRestrictions().Labels, "the metric selector should have matched the one specified")
+
+		metrics := emapi.ExternalMetricValueList{}
+
+		for _, level := range tc.metric.levels {
+			metric := emapi.ExternalMetricValue{
+				Timestamp:  metav1.Time{Time: tc.timestamp},
+				MetricName: tc.metric.name,
+				Value:      *resource.NewMilliQuantity(level, resource.DecimalSI),
+			}
+			metrics.Items = append(metrics.Items, metric)
+		}
+
+		return true, &metrics, nil
+	})
 
 	return fakeClient, fakeMetricsClient, fakeCMClient, fakeEMClient
 }
@@ -280,6 +314,12 @@ func (tc *replicaCalcTestCase) runTest(t *testing.T) {
 		var err error
 		if tc.metric.singleObject != nil {
 			outReplicas, outUtilization, outTimestamp, err = replicaCalc.GetObjectMetricReplicas(tc.currentReplicas, tc.metric.targetUtilization, tc.metric.name, testNamespace, tc.metric.singleObject)
+		} 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)
+			} else if tc.metric.perPodTargetUtilization > 0 {
+				outReplicas, outUtilization, outTimestamp, err = replicaCalc.GetExternalPerPodMetricReplicas(tc.currentReplicas, tc.metric.perPodTargetUtilization, tc.metric.name, testNamespace, tc.metric.selector)
+			}
 		} else {
 			outReplicas, outUtilization, outTimestamp, err = replicaCalc.GetMetricReplicas(tc.currentReplicas, tc.metric.targetUtilization, tc.metric.name, testNamespace, selector)
 		}
@@ -428,6 +468,50 @@ func TestReplicaCalcScaleUpCMObject(t *testing.T) {
 	tc.runTest(t)
 }
 
+func TestReplicaCalcScaleUpCMExternal(t *testing.T) {
+	tc := replicaCalcTestCase{
+		currentReplicas:  1,
+		expectedReplicas: 2,
+		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,
+		expectedReplicas: 2,
+		metric: &metricInfo{
+			name:                "qps",
+			levels:              []int64{8600},
+			targetUtilization:   4400,
+			expectedUtilization: 8600,
+		},
+	}
+	tc.runTest(t)
+}
+
+func TestReplicaCalcScaleUpPerPodCMExternal(t *testing.T) {
+	tc := replicaCalcTestCase{
+		currentReplicas:  3,
+		expectedReplicas: 4,
+		metric: &metricInfo{
+			name:                    "qps",
+			levels:                  []int64{8600},
+			perPodTargetUtilization: 2150,
+			expectedUtilization:     2867,
+			selector:                &metav1.LabelSelector{MatchLabels: map[string]string{"label": "value"}},
+		},
+	}
+	tc.runTest(t)
+}
+
 func TestReplicaCalcScaleDown(t *testing.T) {
 	tc := replicaCalcTestCase{
 		currentReplicas:  5,
@@ -478,6 +562,36 @@ func TestReplicaCalcScaleDownCMObject(t *testing.T) {
 	tc.runTest(t)
 }
 
+func TestReplicaCalcScaleDownCMExternal(t *testing.T) {
+	tc := replicaCalcTestCase{
+		currentReplicas:  5,
+		expectedReplicas: 3,
+		metric: &metricInfo{
+			name:                "qps",
+			levels:              []int64{8600},
+			targetUtilization:   14334,
+			expectedUtilization: 8600,
+			selector:            &metav1.LabelSelector{MatchLabels: map[string]string{"label": "value"}},
+		},
+	}
+	tc.runTest(t)
+}
+
+func TestReplicaCalcScaleDownPerPodCMExternal(t *testing.T) {
+	tc := replicaCalcTestCase{
+		currentReplicas:  5,
+		expectedReplicas: 3,
+		metric: &metricInfo{
+			name:                    "qps",
+			levels:                  []int64{8600},
+			perPodTargetUtilization: 2867,
+			expectedUtilization:     1720,
+			selector:                &metav1.LabelSelector{MatchLabels: map[string]string{"label": "value"}},
+		},
+	}
+	tc.runTest(t)
+}
+
 func TestReplicaCalcScaleDownIgnoresUnreadyPods(t *testing.T) {
 	tc := replicaCalcTestCase{
 		currentReplicas:  5,
@@ -546,6 +660,36 @@ func TestReplicaCalcToleranceCMObject(t *testing.T) {
 	tc.runTest(t)
 }
 
+func TestReplicaCalcToleranceCMExternal(t *testing.T) {
+	tc := replicaCalcTestCase{
+		currentReplicas:  3,
+		expectedReplicas: 3,
+		metric: &metricInfo{
+			name:                "qps",
+			levels:              []int64{8600},
+			targetUtilization:   8888,
+			expectedUtilization: 8600,
+			selector:            &metav1.LabelSelector{MatchLabels: map[string]string{"label": "value"}},
+		},
+	}
+	tc.runTest(t)
+}
+
+func TestReplicaCalcTolerancePerPodCMExternal(t *testing.T) {
+	tc := replicaCalcTestCase{
+		currentReplicas:  3,
+		expectedReplicas: 3,
+		metric: &metricInfo{
+			name:                    "qps",
+			levels:                  []int64{8600},
+			perPodTargetUtilization: 2900,
+			expectedUtilization:     2867,
+			selector:                &metav1.LabelSelector{MatchLabels: map[string]string{"label": "value"}},
+		},
+	}
+	tc.runTest(t)
+}
+
 func TestReplicaCalcSuperfluousMetrics(t *testing.T) {
 	tc := replicaCalcTestCase{
 		currentReplicas:  4,