打开终端，输入以下命令：
docker run hello-world
# Unable to find image 'hello-world:latest' locally
# latest: Pulling from library/hello-world
# 0e03bdcc26d7: Pull complete
# Digest: sha256:4cf9c47f86df71d48364001ede3a4fcd85ae80ce02ebad74156906caff5378bc
# Status: Downloaded newer image for hello-world:latest
#
# 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/
hello-world 是一个测试镜像，它会在终端输出一段文字，说明 docker 安装成功。
现在在终端输入以下命令：
docker ps -a
# CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
# 128ec8ceab71 hello-world "/hello" 14 seconds ago Exited (0) 13 seconds ago exciting_chebyshev
可以看到，docker 会自动创建一个容器，容器名为 exciting_chebyshev，容器 ID 为 128ec8ceab71。