在CentOS 7上杀死后，无法启动Docker服务

这样开始docker工人：

# service docker start 

要阻止它：

 # service docker stop 

不能。 然后kill -9 ...所有正在运行的进程。

重新开始：

 # service docker start 

不能：

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

journalctl -xe日志：

 -- The result is failed. 7月 11 21:17:16 centos75 systemd[1]: Unit docker.service entered failed state. 7月 11 21:17:16 centos75 systemd[1]: docker.service failed. 7月 11 21:17:16 centos75 polkitd[727]: Unregistered Authentication Agent for unix-process:12335:6759586 (system bus name :1.87, object path /org/freedesktop/PolicyKit1/AuthenticationAgent, 7月 11 21:17:43 centos75 polkitd[727]: Registered Authentication Agent for unix-process:12360:6762295 (system bus name :1.88 [/usr/bin/pkttyagent --notify-fd 5 --fallback], object path /org 7月 11 21:17:43 centos75 polkitd[727]: Unregistered Authentication Agent for unix-process:12360:6762295 (system bus name :1.88, object path /org/freedesktop/PolicyKit1/AuthenticationAgent, 7月 11 21:18:13 centos75 chronyd[732]: Source 121.111.253.121 replaced with 59.106.180.168 7月 11 21:19:07 centos75 polkitd[727]: Registered Authentication Agent for unix-process:12387:6770743 (system bus name :1.89 [/usr/bin/pkttyagent --notify-fd 5 --fallback], object path /org 7月 11 21:19:07 centos75 systemd[1]: Starting Docker Application Container Engine... -- Subject: Unit docker.service has begun start-up -- Defined-By: systemd -- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel -- -- Unit docker.service has begun starting up. 7月 11 21:19:07 centos75 dockerd[12404]: time="2017-07-11T21:19:07.768545210-04:00" level=fatal msg="can't create unix socket /var/run/docker.sock: is a directory" 7月 11 21:19:07 centos75 systemd[1]: docker.service: main process exited, code=exited, status=1/FAILURE 7月 11 21:19:07 centos75 systemd[1]: Failed to start Docker Application Container Engine. -- Subject: Unit docker.service has failed -- Defined-By: systemd -- Support: http://lists.freedesktop.org/mailman/listinfo/systemd-devel 

然后运行docker ps返回：

 Cannot connect to the Docker daemon. Is the docker daemon running on this host? 

奇怪。