这个错误提示是在启动docker服务时出错了，可能是由于配置有误或者docker进程已经在运行导致的。建议按照错误提示中提供的命令来查看详细信息。具体操作如下：
- 执行命令systemctl status docker.service，查看docker.service的状态，输出类似下面的内容：
● docker.service - Docker Application Container Engine
Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled)
Drop-In: /etc/systemd/system/docker.service.d
└─http-proxy.conf
Active: failed (Result: exit-code) since Wed 2018-10-31 11:53:20 CST; 13s ago
Docs: https://docs.docker.com
Process: 10879 ExecStart=/usr/bin/dockerd -H fd:// (code=exited, status=1/FAILURE)
Main PID: 10879 (code=exited, status=1/FAILURE)
Oct 31 11:53:20 node2 systemd[1]: docker.service: Service hold-off time over, scheduling restart.
Oct 31 11:53:20 node2 systemd[1]: docker.service: Scheduled restart job, restart counter is at 3.
Oct 31 11:53:20 node2 systemd[1]: Stopped Docker Application Container Engine.
Oct 31 11:53:20 node2 systemd[1]: docker.service: Start request repeated too quickly.
Oct 31 11:53:20 node2 systemd[1]: docker.service: Failed with result 'exit-code'.
Oct 31 11:53:20 node2 systemd[1]: Failed to start Docker Application Container Engine.
- 使用命令journalctl -xe，查看系统日志，输出类似下面的内容：
Oct 31 11:53:20 node2 dockerd[10879]: time="2018-10-31T11:53:20.422013728+08:00" level=warning msg="Your kernel does not support swap memory limit"
Oct 31 11:53:20 node2 dockerd[10879]: time="2018-10-31T11:53:20.422044985+08:00" level=warning msg="Your kernel does not support cgroup rt period"
Oct 31 11:53:20 node2 dockerd[10879]: time="2018-10-31T11:53:20.422055730+08:00" level=warning msg="Your kernel does not support cgroup rt runtime"
Oct 31 11:53:20 node2 dockerd[10879]: Error starting daemon: Devices cgroup isn't mounted
Oct 31 11:53:20 node2 systemd[1]: docker.service: Main process exited, code=exited, status=1/FAILURE
Oct 31 11:53:20 node2 systemd[1]: docker.service: Failed with result 'exit-code'.
Oct 31 11:53:20 node2 systemd[1]: Stopped Docker Application Container Engine.
从上面的日志可以看出，docker启动失败原因是cgroup设备未挂载。解决方法如下：
- 执行命令sudo mount -t cgroup -o devices devices /sys/fs/cgroup/devices，挂载cgroup设备。
- 重新启动docker服务。
这样应该就可以顺利地启动docker服务了。
&1 请帮我分析有什么问题，这是在操作shar..." />
