docker basic concepts
Official document the URL of: https://docs.docker.com/
1. Idea Docker is to achieve the "Build, Ship and Run Any App, Anywhere", that is, through the application package (Packaging), distribution (Distribution), deployment (Deployment), running (Runtime) lifecycle management, to application components level "package once, run anywhere." Here's application component, either a Web application, a compiler environment, can also be a database service platform, operating system or even a cluster.
The underlying principle 2.docker
Linux容器（Linux Containers, LXC）技术
分层文件系统构建和高效的镜像机制3: Benefits of docker
Docker通过容器来打包应用、解耦应用和运行平台。这意味着迁移的时候，需要在新的服务器上启动需要的容器就可以了，无论新旧服务器是否是同一类型的平台.
Δ更快速的交付和部署
Δ更高效的资源利用------Docker是内核级的虚拟化，可以实现更高的性能，同时对资源的额外需求很低
Δ更高效的迁移和扩展
Δ更简单的更新管理
4: docker and compare virtual machine
