安装Docker

（1）:卸载旧版本Docker

     [root@localhost ~]  yum remove docker \
    docker-client \
    docker-client-latest \
    docker-common \
    docker-latest \
    docker-latest-logrotate \
    docker-logrotate \
    docker-selinux \
    docker-engine-selinux \
    docker-engine

（2）：安装必要系统工具

    [root@localhost ~]  yum install -y yum-utils device-mapper-persistent-data lvm2
    [root@localhost ~]  yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
　  [root@localhost ~]  yum makecache fast

（3）：安装Docker-ce

　　 [root@localhost ~]  yum -y install docker-ce

（4）：启动Docket后台服务

     [root@localhost ~]  systemctl enable docker
     [root@localhost ~]  systemctl start docker

（5）：设置sysctl允许网络转发

     [root@localhost ~] vim /etc/sysctl.conf
    新增参数net.ipv4.ip_forward = 1

（6）：设置国内镜像地址

     [root@localhost ~] vim /etc/docker/daemon.json
    {
      "registry-mirrors": [
        "https://hub-mirror.c.163.com",
        "https://mirror.baidubce.com"
      ]
    }
    
    [root@localhost ~] systemctl daemon-reload

完成后重启docker

卸载Docker

    [root@localhost ~] yum remove  docker-ce-cli containerd.io
    [root@localhost ~] rm -rf /var/lib/docker