cat >/etc/yum.repos.d/docker.repo <<-EOF
[dockerrepo]
name=Docker Repository
baseurl=https://yum.dockerproject.org/repo/main/centos/7
enabled=1
gpgcheck=1
gpgkey=https://yum.dockerproject.org/gpg
EOF

#安装
sudo yum install docker-engine
#启动
sudo systemctl enable docker.service
#开机启动
systemctl enable docker.service
#验证安装
sudo docker run hello-world

curl -sSL https://get.docker.com/ | sh

sudo usermod -a -G docker $USER

curl -sSL https://get.daocloud.io/daomonit/install.sh | sh -s 6d3f36d42ae3f3d4237943c65c8f3e5446e49a71

dao pull ubuntu

➜  ~  dao pull ubuntu
Dao from DaoCloud
Initializing, Please wait a minute
Using default tag: latest
Pulling repository daocloud.io/daocloud/daocloud-toolset
aa5dc2eecd4a: Download complete
Status: Image is up to date for daocloud.io/daocloud/daocloud-toolset:latest
daocloud.io/daocloud/daocloud-toolset: this image was pulled from a legacy registry.  Important: This registry version will not be supported in future versions of docker.
Inital Success


# ----------------------------------------------------------------------------
# DaoCloud ToolBox for Docker
#
# DaoCloud, Inc. (c) 2015
#
# Fastest way to pull image from Docker Registry
# ----------------------------------------------------------------------------

Pulling repository ubuntu
Pulling ubuntu image metadata
Pulling ubuntu:latest tag metadata
0105f98ced6d: Load layer complete
66395c31eb82: Load layer complete
002fa881df8a: Load layer complete
a005e6b7dd01: Load layer complete
Loading image to docker ...

** Pull ubuntu success. **
You can find it with 'docker images ubuntu'