1. 获取Docker安装包
   wget -qO- https://get.docker.com/ | sh
   命令执行之后，docker自动安装，完成后执行 docker -v 查看是否安装成功

注意：
安装完成之后会有下列提示
If you would like to use Docker as a non-root user, you should now consider
adding your user to the "docker" group with something like:

sudo usermod -aG docker wnn

Remember that you will have to log out and back in for this to take effect!

WARNING: Adding a user to the "docker" group will grant the ability to run
containers which can be used to obtain root privileges on the
docker host.
Refer to https://docs.docker.com/engine/security/security/#docker-daemon-attack-surface
for more information.

2. 执行命令：sudo usermod -aG docker wnn
3. 用户切换为root
4. Docker命令：
   a. 搜索镜像：docker search XXX
   b. 拉取镜像：docker pull XXX
   c. 查看本地主机的已有镜像：docker images
   d. 查看镜像详细信息：docker inspect
   e. 删除镜像：docker rmi docker.io/ubuntu
   f. 创建镜像：docker run -ti ubuntu /bin/bash
5. Docker 操作：
   a. 直接运行容器中的程序：docker run ubuntu:15.10 /bin/echo "Hello world"
   b. 运行交互式容器：docker run -i -t jenkins/jenkins /bin/bash
   c. 查看运行中的容器：docker ps
   d. 停止容器：docker stop containerId
   e. 映射端口：-p docker run -i -t -p 8080 jenkins/Jenkins 32768是localhost访问端口
   i. root@wnn-virtual-machine:/home/wnn# docker port eea861e45ebc
   ii. 8080/tcp -> 0.0.0.0:32768
   f. 访问web服务