1. This method will install Docker 1.10.3 version.
# yum update
# yum install docker
# systemctl start docker
# systemctl enable docker
2. If you want to install the latest offical version (1.12.1).
# tee /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
# yum update
# yum install docker-engine
# systemctl start docker
# systemctl enable docker
https://wiki.centos.org/zh-tw/Cloud/Docker
https://docs.docker.com/engine/installation/linux/centos/
