一、添加docker官方提供的CentOS 7的yum源:
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
二、安装docker并开机启动
yum install docker-engine
systemctl restart docker.service
systemctl enable docker.service