Introduction to Docker

Let's experiment with Docker containers. Running a container that you can enter commands in is as simple as the following:

docker run --interactive --tty ubuntu:20.04 bash

With this command, we are telling Docker to run the Ubuntu image, which will be fetched from Docker Hub, a central registry of public images. We are providing a tag of 20.04 after the image name so that we download the container image that represents the Ubuntu 20.04 operating system. This won't contain everything that a regular Ubuntu installation has, but anything that's missing is installable.

We also tell Docker to run interactively—the -i argument—and to assign a tty with the -t argument, so that we can type commands inside the container. By default, Docker assumes that you want to start a container that runs in the background, serving requests. By using these two options and asking that the command bash is run inside the container, we can...