docker.service的作业失败，因为控制进程退出并显示错误代码。请参阅＆＃34; systemctl status docker.service＆＃34;和＆＃34; journalctl -xe＆＃34;详情。
systemctl status docker.service：
● docker.service - Docker Application Container Engine
Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled)
Active: inactive (dead) (Result: exit-code) since Fri 2018-04-20 00:30:30 IST; 22s ago
Docs: https://docs.docker.com
Process: 16941 ExecStart=/usr/bin/dockerd -H fd:// (code=exited, status=1/FAILURE)
Main PID: 16941 (code=exited, status=1/FAILURE)
Apr 20 00:30:30 cookie2 systemd[1]: Failed to start Docker Application Container Engine.
Apr 20 00:30:30 cookie2 systemd[1]: docker.service: Unit entered failed state.
Apr 20 00:30:30 cookie2 systemd[1]: docker.service: Failed with result 'exit-code'.
Apr 20 00:30:30 cookie2 systemd[1]: docker.service: Service hold-off time over, scheduling restart.
Apr 20 00:30:30 cookie2 systemd[1]: Stopped Docker Application Container Engine.
Apr 20 00:30:30 cookie2 systemd[1]: docker.service: Start request repeated too quickly.
Apr 20 00:30:30 cookie2 systemd[1]: Failed to start Docker Application Container Engine.