Horizontal Pod Autoscaler（HPA）目标CPU百分比基准值确认

应用部署与服务清单 #

apiVersion: apps/v1
kind: Deployment
metadata:
  name: hpa-demo-deployment
  labels:
    app: hpa-nginx
spec:
  replicas: 1
  selector:
    matchLabels:
      app: hpa-nginx
  template:
    metadata:
      labels:
        app: hpa-nginx
    spec:
      containers:
      - name: hpa-nginx
        image: stacksimplify/kubenginx:1.0.0
        ports:
        - containerPort: 80
        resources:
          requests:
            memory: "128Mi"
            cpu: "100m"
          limits:
            memory: "500Mi"
            cpu: "200m"          
---
apiVersion: v1
kind: Service
metadata:
  name: hpa-demo-service-nginx
  labels:
    app: hpa-nginx
spec:
  type: LoadBalancer
  selector:
    app: hpa-nginx
  ports:
  - port: 80
    targetPort: 80

HPA配置清单 #

apiVersion: autoscaling/v1
kind: HorizontalPodAutoscaler
metadata:
  name: hpa-demo-declarative
spec:
  maxReplicas: 10 # define max replica count
  minReplicas: 1  # define min replica count
  scaleTargetRef:
    apiVersion: apps/v1
    kind: Deployment
    name: hpa-demo-deployment
  targetCPUUtilizationPercentage: 20 # target CPU utilization

问题解答 #

HPA配置中的20%目标CPU利用率，基准是容器定义的requests.cpu（即100m），而非limits.cpu或其他数值。

autoscaling/v1版本的HPA计算CPU使用率时，会拿Pod的实际CPU使用量除以容器的CPU requests值，将得到的百分比与targetCPUUtilizationPercentage对比。比如你当前的配置，当Pod实际CPU使用量达到100m的20%（也就是20m）时，HPA会触发扩容逻辑；反之如果使用率持续低于该值，则会触发缩容。

内容的提问来源于stack exchange，提问作者Mohamed