centos7上docker安装并启动

从包安装，最简安装方式

1. 更新yum yum update
2. 转到 https://download.docker.com/linux/centos/7/x86_64/stable/Packages/ 并下载.rpm要安装的Docker版本的文件
3. 安装Docker CE，将下面的路径更改为您下载Docker软件包的路径。
   # yum install /path/to/package.rpm
   eg：yum install https://yum.dockerproject.org/repo/main/centos/7/Packages/docker-engine-1.10.0-1.el7.centos.x86_64.rpm
   查看安装是否成功docker version，client启动成功
   
4. 启动docker systemctl start docker
   查看启动成功docker version，client和service启动成功
   
   或者运行docker run hello-world 映像验证是否已正确安装
   
5. 设置开机自启动 sudo systemctl enable docker
6. 卸载docker

yum remove docker \
                  docker-client \
                  docker-client-latest \
                  docker-common \
                  docker-latest \
                  docker-latest-logrotate \
                  docker-logrotate \
                  docker-selinux \
                  docker-engine-selinux \
                  docker-engine

资料参考：https://docs.docker.com/install/linux/docker-ce/centos/#upgrade-docker-ce