VirtualBox下载地址 https://www.virtualbox.org/wiki/Downloads
centos7镜像下载以及配置地址https://www.cnblogs.com/hihtml5/p/8217062.html
安装centos7+docker https://blog.csdn.net/bornshare/article/details/45051003
virtualBox 与window界面相互切换 ctrl+右方向键
gnome鼠标不显示 则重新启动虚拟机