一、创建测试Deployment

$ vi php-apache.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: php-apache
spec:
  selector:
    matchLabels:
      run: php-apache
  replicas: 1
  template:
    metadata:
      labels:
        run: php-apache
    spec:
      containers:
      - name: php-apache
        image: registry.cn-hangzhou.aliyuncs.com/abroad_images/hpa-example:latest
        ports:
        - containerPort: 80
        resources:
          limits:
            cpu: 500m  ##限制Pod CPU资源最多使用500m
          requests:
            cpu: 200m  ##K8s要保证Pod使用的最小cpu资源为200m
---
apiVersion: v1
kind: Service
metadata:
  name: php-apache
  labels:
    run: php-apache
spec:
  ports:
  - port: 80
  selector:
    run: php-apache

应用YAML

$ k apply -f php-apache.yaml

• 二、安装merics-server,参考二进制方式安装k8s集群和kubeadm方式安装k8s集群

二、创建HPA

$ vi  hpa-php-apache.yaml

apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
  name: php-apache
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: php-apache
  minReplicas: 1  ##最小Pod数为1
  maxReplicas: 10  ##最大Pod数为10
  metrics:
  - type: Resource
    resource:
      name: cpu
      target:
        type: Utilization
        averageUtilization: 50  ##当Pod的CPU使用率超过50%时，需要自动扩容

三、应用YAML

$ k apply -f hpa-php-apache.yaml

四、再开一个终端,模拟php-apache Pod CPU使用率增加

$ k run -i --tty load-generator --rm --image=registry.cn-hangzhou.aliyuncs.com/abroad_images/busybox:latest --restart=Never -- /bin/sh -c "while sleep 0.01; do wget -q -O- http://php-apache; done"

五、回到原来终端查看po,观察到随着CPU使用率增加，Pod的副本数随之也增加

$ while : ; do k get po | grep php-apache | wc -l; sleep 3; done
5

$ k get hpa
NAME         REFERENCE               TARGETS    MINPODS   MAXPODS   REPLICAS   AGE
php-apache   Deployment/php-apache   242%/50%   1         10        5          81m

六、停止模拟php-apache Pod CPU使用率增加后，继续回到原来终端查看po,观察到随着CPU使用率减少，Pod的副本数随之也减少

$ k get hpa

NAME         REFERENCE               TARGETS   MINPODS   MAXPODS   REPLICAS   AGE
php-apache   Deployment/php-apache   0%/50%    1         10        1          6h41m

七、恢复

$ k delete -f hpa-php-apache.yaml
$ k delete -f php-apache.yaml