执行Docker命令，提示没有权限的对应方法

$ docker image ls
Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Get http://%2Fvar%2Frun%2Fdocker.sock/v1.40/images/json: dial unix /var/run/docker.sock: connect: permission denied

$ docker image ls
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
hello-world         latest              bf756fb1ae65        6 months ago        13.3kB

$ sudo groupadd docker
groupadd：“docker”组已存在

$ sudo gpasswd -a zyy docker
正在将用户“zyy”加入到“docker”组中

sudo service docker restart

/$ exit
exit
# su zyy
/$ docker image ls
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
hello-world         latest              bf756fb1ae65        6 months ago        13.3kB