1、在CentOS7上安装Docker还是比较简单的。CentOS本身就有提供一个docker版本可以安装，但版本较旧，不推荐使用。# yum list|grep dockerdocker.x86_64 1.13.1-102.git7f2769b.el7.centos
2、要想安装最新版的Docker版本，还是需要从Docker官网下载repo文件来进行安装。把repo文件下载到/etc/yum.repos.d目录下。#cd /etc/yum.repos.d#curl -O https://download.docker.com/linux/centos/docker-ce.repo
3、开始安装：# yum install docker-ce主要是安装了三个软件docker-ce、containerd.io和docker-ce-cli。
4、启动Docker服务# systemctl restart docker# systemctl status docker
5、查看当前Docker的版本信息# docker versionClient: Docker Engine - CommunityVersion: 19.03.2API version: 1.40Go version: go1.12.8Git commit: 6a30dfcBuilt: Thu Aug 29 05:28:55 2019OS/Arch: linux/amd64Experimental: falseServer: Docker Engine - CommunityEngine:Version: 19.03.2API version: 1.40 (minimum version 1.12)Go version: go1.12.8Git commit: 6a30dfcBuilt: Thu Aug 29 05:27:34 2019OS/Arch: linux/amd64Experimental: false