Job for docker.service failed because the control process exited with error code. See "systemctl sta

 docker启动的时候出现这个错误:

Job for docker.service failed because the control process exited
 with error code. See "systemctl status docker.service" 
and "journalctl -xe" for details.

 原因：daemon.json 的json格式不对，如下：

{
  "registry-mirrors": [
    "https://rj4f7247.mirror.aliyuncs.com"
  ]
  "log-driver":"json-file",
  "log-opts":{ "max-size" :"100m","max-file":"1"}
}

 缺少一个逗号