我已经安装docker在ubuntu 14.04，它告诉我安装成功。然后我进入sudo docker版本，它返回
Client: Version: 1.9.1 API version: 1.21 Go version: go1.4.2 Git commit: a34a1d5 Built: Fri Nov 20 13:12:04 UTC 2015 OS/Arch: linux/amd64 Cannot connect to the Docker daemon. Is the docker daemon running on this host?
我进入sudo服务docker状态，我得到了
docker start/running,process 8063
我试过sudo docker图像和sudo docker信息，我得到相同的答复：
Cannot connect to the Docker daemon. Is the docker daemon running on this host?
我不知道为什么它返回这个，我试图拉ubuntu使用sudo docker拉ubuntu，并得到了
Using default tag: latest Cannot connect to the Docker daemon. Is the docker daemon running on this host?
请告诉我如何解决这个问题，我该如何拉和运行docker镜像。是docker -d和docker deamon一样吗？
您需要将当前用户添加到docker组，如下所示：
sudo usermod -aG docker <your username>
另外，可以使用USER环境变量如：
sudo usermod -aG docker $USER
然后重新启动系统。因为docker documentation说：
The docker daemon binds to a Unix socket instead of a TCP port. By default that
Unix socket is owned by the user root and other users can access it
withsudo. For this reason,docker daemon always runs as the root
user.To avoid having to use
@H_403_58@sudowhen you use thedockercommand,create a
Unix group calleddockerand add users to it. When the docker daemon
starts,it makes the ownership of the Unix socket read/writable by the
dockergroup.
