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

if first time to install docker, be noted the docker engine started as root

copied from: http://blog.163.com/s2006203387@126/blog/static/533199572015111703735423/

Ubuntu 14.04

第一次安装Docker，运行hello-world 是能够的，

重启系统以后，运行hello-world 出现以下报错：

 

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

 

 

多方查找，解决以下：

sudo su -                       //切换到root

service docker start      //启动docker service

docker images              //显示全部images

docker run hello-world  //从新运行

 

恩，是权限问题，当前用户没权限，root用户能够运行