五、启动、退出动作

main containers启动之前还会有个start动作，结束后有个stop动作

示例：

apiVersion: v1
kind: Pod
metadata:
  name: lifecycle-demo
spec:
  containers:
  - name: lifecycle-demo-nginx
    image: nginx:1.15
    lifecycle:
      postStart:
        exec:
          command: ["/bin/sh","-c","echo hello world >/root/test"]
      postStop:
        exec:
          command: ["/usr/sbin/nginx","-s","quit"]