kubernetes之Pod水平自動伸縮(HPA)

https://k8smeetup.github.io/docs/tasks/run-application/horizontal-pod-autoscale-walkthrough/

Horizontal Pod Autoscaling能夠根據CPU利用率自動伸縮一個Replication Controller、Deployment 或者Replica Set中的Pod數量。

Horizontal Pod Autoscaler須要使用 Heapster所收集到的 度量數據，請確保Heapster被正確部署到Kubernetes集羣中。

使用nginx測試

1）建立deployment和service

[root@node-01 ~]# cat deployment-nginx.yaml apiVersion: apps/v1beta1 kind: Deployment metadata: name: nginx-deployment spec: replicas: 2 # tells deployment to run 2 pods matching the template template: # create pods using pod definition in this template metadata: labels: app: nginx spec: nodeSelector: app: nginx containers: - name: nginx image: nginx:1.8 ports: - containerPort: 80 livenessProbe: httpGet: path: / port: 80 initialDelaySeconds: 10 timeoutSeconds: 2 periodSeconds: 10 resources: limits: cpu: 200m memory: 30Mi requests: cpu: 100m memory: 20Mi --- apiVersion: v1 kind: Service metadata: name: nginx-deployment labels: app: nginx-deployment spec: ports: - port: 80 protocol: TCP selector: app: nginx

[root@node-01 ~]# kubectl apply -f deployment-nginx.yaml

建立一個HPA控制器，用於監控對象資源利用率

kubectl autoscale deployment nginx-deployment --min=2 --max=6 --cpu-percent=50 # 對nginx的deployment的對象建立HPA控制器，當CPU的使率超過50%時實現自動化擴容，支持1到6以前Pod副本數量，以使得Pod CPU使用率維持在50% 之內。

增長負載

$ kubectl run -i --tty load-generator --image=busybox /bin/sh Hit enter for command prompt $ while true; do wget -q -O- http://nginx-deployment; done

檢查pod的負載狀況

[root@node-01 ~]# kubectl get hpa NAME REFERENCE TARGETS MINPODS MAXPODS REPLICAS AGE nginx-deployment   Deployment/nginx-deployment   4%/20%    2         5         2 28h [root@node-01 ~]# kubectl get hpa NAME REFERENCE TARGETS MINPODS MAXPODS REPLICAS AGE nginx-deployment   Deployment/nginx-deployment   64%/20%   2         5         5          28h

同時看到replicas已經增長到了5，測試完成。

注意 自動伸縮完成副本數量的改變可能須要幾分鐘的時間。