基于k8s的HAP进行容器的水平伸缩

前置条件：

1、阿里云ack集群

操作：

以nginx服务为例

step1:创建nginx的deployment

cat nginx-deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx
  labels:
    app: nginx
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:latest
        ports:
        - containerPort: 80
        ##必须设置，不然HPA无法运行
        resources:
          requests:
            cpu: 5m  #设置0.005cpu，小一些容易看出效果
---
apiVersion: v1
kind: Service
metadata:
  name: nginx
  namespace: default
spec:
  ports:
    - port: 80
      protocol: TCP
      targetPort: 80
  selector:
    app: nginx
  type: ClusterIP

kubectl apply -f nginx-deployment.yaml

step2:创建hpa

cat nginx-hpa-sp.yaml

apiVersion: autoscaling/v2beta2
kind: HorizontalPodAutoscaler
metadata:
  name: nginx-hpa
spec:
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: nginx
  minReplicas: 1
  maxReplicas: 10
  metrics:
  - type: Resource
    resource:
      name: cpu
      target:
        type: Utilization
        averageUtilization: 5   #cpu使用率超过5%

kubectl apply -f nginx-hpa-sp.yaml

step3:模拟超载访问

for i in `seq 1 100000`
do
curl 172.20.103.97
echo $i
done

过程如下：

可以发现，单个pod在cpu超过5%后（单个pod cpu的request为5m，也就是说超过0.25m后就会触发），hpa会自动触发然后扩容


手动终止连续访问，会发现pod的cpu降下来了，然后大约在五分钟左右会自动缩容


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