1.离线安装
相关安装包地址：
https://download.docker.com/linux/static/stable/x86_64/
1.解压安装包
tar -zxvf /opt/cosmo/docker-18.03.1-ce.tgz
2.解压缩后的文件拷贝到对应目录
cp docker/* /usr/bin/
3.注册docker服务
vi docker.service
[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
将docker.service 拷贝到对应目录下：
cp docker.service /usr/lib/systemd/system/
4.启动和验证，启动docker服务：
systemctl start docker
验证是否成功:
docker -v
2.在线安装
可以参考菜鸟教程
https://www.runoob.com/docker/centos-docker-install.html
如：使用国内 daocloud 一键安装命令：
curl -sSL https://get.daocloud.io/docker | sh
3.卸载
一般你咋安装的，你就卸载哪里就好了，一般都是上面的安装步骤。
卸载前停止docker的运行
systemctl status docker
systemctl stop docker
查看yum安装的docker文件包
yum list installed |grep docker
查看docker相关的rpm源文件
rpm -qa |grep docker
删除所有安装的docker文件包
yum -y remove docker-ce.x86_64
其他docker相关的安装包同样删除操作，删完之后可以再查看下docker rpm源
rpm -qa |grep docker
检查目录/usr/bin/，里面是否有docker有则删除
检查/usr/lib/systemd/system/docker.service是否存咋，存在删除
删除docker的镜像文件，默认在/var/lib/docker目录下
rm -rf /var/lib/docker
Over.