Implement horizontal auto scaling based on Alibaba Cloud metrics

apiVersion: apps/v1 
kind: Deployment
metadata:
  name: nginx-deployment-basic
  labels:
    app: nginx
spec:
  replicas: 2
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.7.9 
        ports:
        - containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
  name: nginx
  namespace: default
spec:
  ports:
    - port: 80
      protocol: TCP
      targetPort: 80
  selector:
    app: nginx
  type: ClusterIP

1. Click in the upper-left corner to return to the Clusters page.
2. In the left-side navigation pane of the ACK console, choose Marketplace > Orchestration Templates.
3. On the Templates page, select hpa and click Create Application to deploy an application with the following YAML file:

   apiVersion: autoscaling/v2
   kind: HorizontalPodAutoscaler
   metadata:
     name: ingress-hpa
   spec:
     scaleTargetRef:
       apiVersion: apps/v1
       kind: Deployment
       name: nginx-deployment-basic
     minReplicas: 2
     maxReplicas: 10
     metrics:
       - type: External
         external:
           metric:
             name: sls_ingress_qps
             selector:
               matchLabels:
                 sls.project: "***" # Replace sls.project with the actual value. 
                 sls.logstore: "nginx-ingress"
                 sls.ingress.route: "default-nginx-80"
           target:
             type: AverageValue
             averageValue: 10
       - type: External
         external:
           metric:
             name: sls_ingress_latency_p9999
             selector:
               matchLabels:
                 # default ingress log project is k8s-log-clusterId
                 sls.project: "****" 
                 # default ingress logstre is nginx-ingress
                 sls.logstore: "nginx-ingress"
                 # namespace-svc-port
                 sls.ingress.route: "default-nginx-80"
                 # sls vpc endpoint, default true
                 # sls.internal.endpoint:ture
           target:
             type: Value
             # sls_ingress_latency_p9999 > 10ms
             value: 10

   The following table describes the parameters that are used to configure HPA.

   Parameter	Description
   sls.ingress.route	Set the value in the <namespace>-<svc>-<port> format, for example, default-nginx-80. This parameter is required. Note <namespace> specifies the namespace to which the Ingress belongs. <svc> specifies the name of the Service that you selected when you created the Ingress. <port> specifies the port of the Service.
   sls.logstore	The name of the Logstore in Log Service. This parameter is required.
   sls.project	The name of the Log Service project. This parameter is required.
   sls.internal.endpoint	Specifies whether to access Log Service over the internal network or the Internet. Default value: true. If you set the value to true, you access Log Service over the internal network. If you set the value to false, you access Log Service over the Internet.

   Note

   The sls_ingress_qps and sls_ingress_latency_p9999 metrics are used by HPA to automatically scale the number of pods. In the target sections, each metric has a different type value:

   • The type value of the sls_ingress_qps metric is set to AverageValue. This indicates that the metric value is the result of dividing the total QPS by the number of pods.
   • The type value of the sls_ingress_latency_p9999 metric is set to Value. This indicates that the latency is not divided by the number of pods.

   The two type values are commonly used in HPA configurations.
4. In the upper-right corner of the Templates - HPA page, click Create.

#!/bin/bash
##Use Apache Benchmark to send requests to the Service exposed by the Ingress. The test lasts 300 seconds and 10 concurrent requests are sent per second. 
ab -t 300 -c 10 <The domain name of the Ingress>

1. In the left-side navigation pane of the ACK console, click Clusters. On the Clusters page, find the cluster that you want to manage and choose More > Open Cloud Shell in the Actions column.
2. Run the following command to check the status of HPA:

   kubectl get hpa ingress-hpa

   Expected output:

   NAME            REFERENCE                              TARGETS           MINPODS    MAXPODS    REPLICAPS   AGE
   ingress-hpa     Depolyment/nginx-deployment-basic      21/10 (avg)       2          10         10          7m49s

   If the value of REPLICAS is the same as the value of MAXPODS, it indicates that HPA scaled out the number of pods as expected.