Code change:
// return the current replicas if the change would be too small return currentReplicas, utilization, timestamp, nil } <del> replicaCount = int32(math.Ceil(usageRatio * float64(currentReplicas))) </del> <ins> readyPodCount, err := c.getReadyPodsCount(namespace, selector) if err != nil { return 0, 0, time.Time{}, fmt.Errorf("unable to calculate ready pods: %s", err) } replicaCount = int32(math.Ceil(usageRatio * float64(readyPodCount))) </ins> return replicaCount, utilization, timestamp, nil } <ins> // @TODO(mattjmcnaughton) Many different functions in this module use variations // of this function. Make this function generic, so we don't repeat the same // logic in multiple places. func (c *ReplicaCalculator) getReadyPodsCount(namespace string, selector labels.Selector) (int64, error) { podList, err := c.podsGetter.Pods(namespace).List(metav1.ListOptions{LabelSelector: selector.String()}) if err != nil { return 0, fmt.Errorf("unable to get pods while calculating replica count: %v", err) } if len(podList.Items) == 0 { return 0, fmt.Errorf("no pods returned by selector while calculating replica count") } readyPodCount := 0 for _, pod := range podList.Items { if pod.Status.Phase == v1.PodRunning && podutil.IsPodReady(&pod) { readyPodCount++ } } return int64(readyPodCount), nil } </ins> // 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. <del> 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) </del> <ins> 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) </ins> if err != nil { return 0, 0, time.Time{}, err } <del> metrics, timestamp, err := c.metricsClient.GetExternalMetric(metricName, namespace, labelSelector) </del> <ins> metrics, timestamp, err := c.metricsClient.GetExternalMetric(metricName, namespace, metricLabelSelector) </ins> if err != nil { <del> return 0, 0, time.Time{}, fmt.Errorf("unable to get external metric %s/%s/%+v: %s", namespace, metricName, selector, err) </del> <ins> return 0, 0, time.Time{}, fmt.Errorf("unable to get external metric %s/%s/%+v: %s", namespace, metricName, metricSelector, err) </ins> } utilization = 0 for _, val := range metrics { utilization = utilization + val } <ins> readyPodCount, err := c.getReadyPodsCount(namespace, podSelector) if err != nil { return 0, 0, time.Time{}, fmt.Errorf("unable to calculate ready pods: %s", err) } </ins> 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 } <del> return int32(math.Ceil(usageRatio * float64(currentReplicas))), utilization, timestamp, nil </del> <ins> return int32(math.Ceil(usageRatio * float64(readyPodCount))), utilization, timestamp, nil </ins> } // 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. <del> 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) </del> <ins> 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) </ins> if err != nil { return 0, 0, time.Time{}, err } <del> metrics, timestamp, err := c.metricsClient.GetExternalMetric(metricName, namespace, labelSelector) </del> <ins> metrics, timestamp, err := c.metricsClient.GetExternalMetric(metricName, namespace, metricLabelSelector) </ins> if err != nil { <del> return 0, 0, time.Time{}, fmt.Errorf("unable to get external metric %s/%s/%+v: %s", namespace, metricName, selector, err) </del> <ins> return 0, 0, time.Time{}, fmt.Errorf("unable to get external metric %s/%s/%+v: %s", namespace, metricName, metricSelector, err) </ins> } utilization = 0 for _, val := range metrics {

Related discussion:
text: without this feature we cannot use HPA as is and we need to figure out how to build/run fork (which can be challenging because everything inside controller-manager). also we are planning to upgrade to 1.10 quickly, but not sure for 1.11 (e.g. we are two versions behind now).
Sounds like a plan :) Will try and get this done tomorrow morning!
- I submitted a pr for this - would love your eyes on it so you can see if you think it meets your use case :)
/assign
GitHub didn't allow me to assign the following users: mattjmcnaughton. Note that only and repo collaborators can be assigned. <detailsIn response to : /assign Instructions for interacting with me using PR comments are available . If you have questions or suggestions related to my behavior, please file an issue against the repository. </details
I checked the code and it seems good to me. About the comment about scaling down if the readyPods<CurrentPods, we should be fine since our metric is already not including the pods that are not ready.
Is there any advance in this ticket? I'm wondering if this made it to k8s 1.10 or if we need to wait for k8s 1.11?
The PR is lgtm-ed and it will merge once the code freeze is lifted. Meaning it will go to 1.11. To get it into 1.10 you would need to get approval for milestone from (sig-autoscaling lead).