1、安装环境
此处在Centos7进行安装，可以使用以下命令查看CentOS版本
lsb_release -a
在 CentOS 7安装docker要求系统为64位、系统内核版本为 3.10 以上，可以使用以下命令查看
uname -r
2、用yum源安装
2.1 查看是否已安装docker列表
yum list installed | grep docker
2.2 安装docker
yum -y install docker
-y表示不询问安装，直到安装成功，安装完后再次查看安装列表
2.3 启动docker
systemctl start docker
2.4 查看docker服务状态
systemctl status docker
以上说明docker安装成功
3、离线安装模式
3.1 安装包官方地址：https://download.docker.com/linux/static/stable/x86_64/
可以先下载到本地，然后通过ftp工具上传到服务器上，或者在服务器上使用命令下载
wget https://download.docker.com/linux/static/stable/x86_64/docker-18.06.3-ce.tgz
3.2 解压
tar -zxvf docker-18.06.3-ce.tgz
3.3 将解压出来的docker文件复制到 /usr/bin/ 目录下
cp docker/* /usr/bin/
3.4 在/etc/systemd/system/目录下新增docker.service文件，内容如下，这样可以将docker注册为service服务
[Unit] Description=Docker Application Container Engine Documentation=https://docs.docker.com After=network-online.target firewalld.service Wants=network-online.target[Service]
=notify
Typethe default is not to use systemd
for cgroups because the delegate issues stillexists and systemd currently does not support the cgroup feature set required
for containers run by dockerExecStart
=/usr/bin/dockerd --selinux-enabled=false --insecure-registry=127.0.0.1
ExecReload=/bin/kill -s HUP $MAINPIDHaving non
-zero Limit*s causes performance problems due to accounting overhead in the kernel. We recommend using cgroups to do container-local accounting.LimitNOFILE
=infinity
LimitNPROC=infinity
LimitCORE=infinityUncomment TasksMax
if your systemd version supports it.Only systemd
226 and above support this version.TasksMax
=infinityTimeoutStartSec
=0set delegate yes so that systemd does not reset the cgroups of docker containers
Delegate
=yes kill only the docker process, not all processes in the cgroupKillMode
=processrestart the docker process
if it exits prematurelyRestart
=on-failure
StartLimitBurst=3
StartLimitInterval=60s[Install]
=multi-user.target
WantedBy
此处的--insecure-registry=127.0.0.1（此处改成你私服ip）设置是针对有搭建了自己私服Harbor时允许docker进行不安全的访问，否则访问将会被拒绝。
3.5 启动docker
给docker.service文件添加执行权限
chmod +x /etc/systemd/system/docker.service
重新加载配置文件（每次有修改docker.service文件时都要重新加载下）
systemctl daemon-reload
启动
systemctl start docker
设置开机启动
systemctl enable docker.service
查看docker服务状态
systemctl status docker
上图表示docker已安装成功
原文：https://www.cnblogs.com/ziweijun/p/13171679.html