Container Service for Kubernetes:Configure custom metrics using AHPA for application scaling

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

Click the name of your cluster. In the left navigation pane, click Workloads > Deployments.

On the Deployments page, click Create from YAML. Paste the following YAML, then click Create. This deploys:

• sample-app: a server that exposes the requests_per_second metric at /metrics on port 8080

• fib-loader-qps: a load generator that sends traffic to sample-app

apiVersion: apps/v1
kind: Deployment
metadata:
  name: sample-app
  labels:
    app: sample-app
spec:
  replicas: 1
  selector:
    matchLabels:
      app: sample-app
  template:
    metadata:
      labels:
        app: sample-app
    spec:
      containers:
      - image: registry.cn-hangzhou.aliyuncs.com/acs/knative-sample-fib-server:v1
        name: metrics-provider
        ports:
        - name: http
          containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
  name: sample-app
  namespace: default
  labels:
    app: sample-app
spec:
  ports:
    - port: 8080
      name: http
      protocol: TCP
      targetPort: 8080
  selector:
    app: sample-app
  type: ClusterIP
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: fib-loader-qps
  namespace: default
spec:
  progressDeadlineSeconds: 600
  replicas: 1
  revisionHistoryLimit: 10
  selector:
    matchLabels:
      app: fib-loader-qps
  strategy:
    rollingUpdate:
      maxSurge: 25%
      maxUnavailable: 25%
    type: RollingUpdate
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: fib-loader-qps
    spec:
      containers:
      - args:
        - -c
        - |
          /ko-app/fib-loader --service-url="http://sample-app.${NAMESPACE}:8080/" --save-path=/tmp/fib-loader-chart.html
        command:
        - sh
        env:
        - name: NAMESPACE
          valueFrom:
            fieldRef:
              apiVersion: v1
              fieldPath: metadata.namespace
        image: registry.cn-huhehaote.aliyuncs.com/kubeway/knative-sample-fib-loader:20201126-110434
        imagePullPolicy: IfNotPresent
        name: loader
        ports:
        - containerPort: 8090
          name: chart
          protocol: TCP

Log on to the ARMS console. In the left navigation pane, click Integration Management.

On the Integrated Environments tab, click the Container Service tab. Find your ACK instance and click Metric Scraping in the Actions column.

On the Metric Collection page, click the Service Monitor tab. Find sample-app, click Enable in the Actions column, and confirm.

Log on to the ARMS console. In the left navigation pane, choose Managed Service for Prometheus > Instances.

On the Prometheus Instances page, select the region of your instance and click the instance name. Instance names follow the format arms_metrics_{RegionId}_XXX.

In the left navigation bar, click Settings. Under HTTP API Address (Grafana Read Address), copy the Internal network URL.

• If token-based authentication is enabled for your instance, also copy the access token.

In the ACK console, click Marketplace > Marketplace in the left navigation pane.

Click the App Catalog tab, search for ack-alibaba-cloud-metrics-adapter, and click Deploy in the upper-right corner.

On the Basic Information page, select your Cluster and Namespace, then click Next.

In the Parameter Configuration wizard, select a Chart Version. In the Parameters area, set the following values, then click OK.

prometheus:
  enabled: true
  # Required: the internal network URL of Managed Service for Prometheus
  url: http://cn-beijing-intranet.arms.aliyuncs.com:9090/api/v1/prometheus/<instance-id>/<uid>/<cluster-id>/<region>
  # Required only if token-based authentication is enabled
  prometheusHeader:
  - Authorization: <your-access-token>

In the ACK console, click Applications > Helm in the left navigation pane. Find alibaba-cloud-metrics-adapter and click Update in the Actions column.

Copy the following YAML content and paste it to overwrite the corresponding parameters in the template. Note that the requests_per_second parameter must be changed to the actual Prometheus metric name. Then, click Update.

The following is a partial configuration snippet. Paste it to overwrite the corresponding parameters in the existing template; do not replace the entire Helm values file.

......
prometheus:
  adapter:
    rules:
      custom:
      - metricsQuery: sum(<<.Series>>{<<.LabelMatchers>>})
        name:
          as: requests_per_second   # Name exposed to the External Metrics API
        resources:
          overrides:
            namespace:
              resource: namespace
        seriesQuery: requests_per_second  # Must match the metric name in Prometheus
      default: false
enabled: true   # Set to true to enable the Prometheus adapter
......

Verify the metric is available via the External Metrics API:

 kubectl get --raw "/apis/external.metrics.k8s.io/v1beta1/namespaces/default/requests_per_second"

Expected output:

 {"kind":"ExternalMetricValueList","apiVersion":"external.metrics.k8s.io/v1beta1","metadata":{},"items":[{"metricName":"requests_per_second","metricLabels":{},"timestamp":"2023-08-15T07:59:09Z","value":"10"}]}

If the metric appears in the response, the adapter is correctly configured.