docker安装：

    1下载：

        https://get.docker.com/builds/Linux/x86_64/docker-1.12.3.tgz

    2解压并查看docker版本：

        补充： --strip-components N   去除N层目录结构   -C指定解压位置 

    3 在防火墙上打开docker对应端口，（明哥不确定这一步需不需要，这里先略过。后面我还会再回来的）

    4启动docker

    5这里需要有一个开机自启动的脚本（这个shell脚本是我复制过来的，实际上只运行到第四步即可）

        1编写开机启动脚本

            vi /usr/lib/systemd/system/docker.service

                [Unit]

                Description=Docker Application Container Engine

                Documentation=https://docs.docker.com

                After=network.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/local/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

                [Install]

                WantedBy=multi-user.target

        2设置开机启动

                systemctl enable docker.service

        3重启服务器

                reboot