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    Container Service for Kubernetes:Use HPA in Knative

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    Container Service for Kubernetes:Use HPA in Knative

    Last Updated:Mar 25, 2026

    By default, Knative scales workloads based on request count using the Knative Pod Autoscaler (KPA). If your workloads are CPU-bound or memory-bound rather than request-driven, you can switch to the Horizontal Pod Autoscaler (HPA) to scale on CPU utilization or memory utilization instead.

    Prerequisites

    Before you begin, ensure that you have:

    Step 1: Deploy a Knative service

    1. Log on to the ACK console. In the left-side navigation pane, click Clusters.

    2. On the Clusters page, find the cluster that you want to manage and click its name. In the left-side pane, choose Applications > Knative.

    3. On the Services tab of the Knative page, select default from the Namespace drop-down list, click Create from Template, copy the following YAML content to the code editor, and then click Create. The following sample creates a Knative service named helloworld-go-hpa with HPA configured to scale on CPU utilization:

      apiVersion: serving.knative.dev/v1
kind: Service
metadata:
  name: helloworld-go-hpa
spec:
  template:
    metadata:
      labels:
        app: helloworld-go-hpa
      annotations:
        autoscaling.knative.dev/class: "hpa.autoscaling.knative.dev"  # Use HPA instead of the default KPA
        autoscaling.knative.dev/metric: "cpu"                          # Scale on CPU utilization
        autoscaling.knative.dev/target: "30"                           # Scale out when CPU utilization exceeds 30%
        autoscaling.knative.dev/minScale: "1"                          # Keep at least 1 pod running
        autoscaling.knative.dev/maxScale: "4"                          # Cap at 4 pods
    spec:
      containers:
        - image: registry.cn-hangzhou.aliyuncs.com/knative-sample/autoscale-go:v1024
          resources:
            requests:
              cpu: '200m'

    4. Run the following command to verify the Knative service is ready:

      kubectl get ksvc

      Expected output:

      NAME                   URL                                               LATESTCREATED                LATESTREADY                  READY   REASON
helloworld-go-hpa      http://helloworld-go-hpa.default.example.com      helloworld-go-hpa-00001      helloworld-go-hpa-00001      True

      True in the READY column confirms the service is running.

    Step 2: Test autoscaling with a load test

    This step uses hey, an HTTP load testing tool, to drive CPU utilization above the threshold and observe HPA scaling pods out.

    1. Install hey. For installation instructions, see Hey.

    2. Run a 60-second load test at 100 queries per second (QPS):

      hey -z 60s -q 100 \
  -host "helloworld-go-hpa.default.example.com" \
  "http://<gateway-ip>?prime=40000000"

      Replace <gateway-ip> with the IP address or domain name of the gateway.

    3. While the load test runs, watch pod scaling in a separate terminal:

      kubectl get pods --watch

      Expected output:

      NAME                                                     READY   STATUS              RESTARTS   AGE
helloworld-go-hpa-00001-deployment-67cc8f979b-fxfl5      2/2     Running             0          101m
helloworld-go-hpa-00001-deployment-67cc8f979b-kv6rj      0/2     Pending             0          0s
helloworld-go-hpa-00001-deployment-67cc8f979b-fxq85      0/2     Pending             0          0s
helloworld-go-hpa-00001-deployment-67cc8f979b-kv6rj      0/2     ContainerCreating   0          0s
helloworld-go-hpa-00001-deployment-67cc8f979b-fxq85      0/2     ContainerCreating   0          0s
helloworld-go-hpa-00001-deployment-67cc8f979b-kv6rj      1/2     Running             0          1s
helloworld-go-hpa-00001-deployment-67cc8f979b-kv6rj      2/2     Running             0          1s
helloworld-go-hpa-00001-deployment-67cc8f979b-fxq85      1/2     Running             0          1s
helloworld-go-hpa-00001-deployment-67cc8f979b-fxq85      2/2     Running             0          1s

      HPA scales the pod count from 1 to 4 as CPU utilization exceeds the 30% threshold. Each pod progresses through Pending -> ContainerCreating -> Running.

    (Optional) Step 3: View the Knative dashboard

    Knative provides out-of-the-box observability for Knative services. View the dashboard on the Monitoring Dashboards tab of the Knative page. For setup and usage, see View the Knative dashboard in Managed Service for Prometheus.

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