前言：

        有些机器没法联网，但是需要使用 docker 服务，所以就需要离线安装 docker。

一、 获取安装包

安装包下载地址：https://download.docker.com/linux/static/stable/x86_64/

从中选择一个比较稳定的版本，下载后并上传到服务器

 二、 安装docker

        1. 解压 docker 压缩文件到 /usr/bin/ 目录下

tar -xvf docker-18.06.1-ce.tgz
cp docker/* /usr/bin/

        2. 准备 docker.service 文件

[Unit]
Description=Docker Application Container Engine
Documentation=https://docs.docker.com
After=network-online.target firewalld.service
Wants=network-online.target

[Service]
Type=notify
# the default is not to use systemd for cgroups because the delegate issues still
# exists and systemd currently does not support the cgroup feature set required
# for containers run by docker
ExecStart=/usr/bin/dockerd
ExecReload=/bin/kill -s HUP $MAINPID
# Having 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=infinity
# Uncomment TasksMax if your systemd version supports it.
# Only systemd 226 and above support this version.
#TasksMax=infinity
TimeoutStartSec=0
# set 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 cgroup
KillMode=process
# restart the docker process if it exits prematurely
Restart=on-failure
StartLimitBurst=3
StartLimitInterval=60s

[Install]
WantedBy=multi-user.target

        3. docker.service 文件拷贝到 /etc/systemd/system/ 目录，并给与执行权限

cp docker.service /etc/systemd/system/
chmod +x /etc/systemd/system/docker.service

        4. 启动 docker 服务

systemctl daemon-reload                 #重新加载配置文件
systemctl start docker                  #启动Docker
systemctl enable docker.service         #设置开机自启

        5. 验证 docker 服务状态

systemctl status docker