Day 6 不免俗的来个 Hello World Docker

Docker 官方制作了一个有趣的 Hello-world docker 映像档，现在就来拉取下来跑起来，顺便复习一下语法并看看内容吧。

步骤

1. 执行 docker pull hello-world
2. 完成後，执行 docker run hello-world
3. 接着会在命令列中，看到以下的字样：

Hello from Docker!
This message shows that your installation appears to be working correctly.

To generate this message, Docker took the following steps:
 1. The Docker client contacted the Docker daemon.
 2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
    (amd64)
 3. The Docker daemon created a new container from that image which runs the
    executable that produces the output you are currently reading.
 4. The Docker daemon streamed that output to the Docker client, which sent it
    to your terminal.

To try something more ambitious, you can run an Ubuntu container with:
 $ docker run -it ubuntu bash

Share images, automate workflows, and more with a free Docker ID:
 https://hub.docker.com/

For more examples and ideas, visit:
 https://docs.docker.com/get-started/

这个 hello-world docker 映像档内，简单介绍方才你的一系列 docker 指令，其在背後做的事情：

1. Docker 客户端连到 docker 执行程序
2. Docker 执行程序 从 docker-hub 拉取 "hello-world" 映像档
3. Docker 由这个 "hello-world" 映像档产生一个容器，并产出上述文字
4. Docker 将容器生出的文字输出到客户端的命令列上

这由官方所提供的映像档，其评价相当不错呢！或许这是个官方所提供的程序工具彩蛋~