Docker实践：Cannot connect to the Docker daemon.

查看docker daemon是否在运行  

[root@localhost openec]#  ps aux | grep docker

root      3030  0.0  0.0 112656   984 pts/0    S+   16:20   0:00 grep --color=auto docker

启动docker

[root@localhost openec]# service docker start

Redirecting to /bin/systemctl start  docker.service