This lesson is being piloted (Beta version)



Teaching: 5 min
Exercises: 5 min
  • What are containers?

  • First learning objective.


The official Docker documentation and tutorial can be found on the Docker website. It is quite thorough and useful. It is an excellent guide that should be routinely visited, but the emphasis of this introduction is on using Docker, not how Docker itself works.

A note up front, Docker has very similar syntax to Git and Linux, so if you are familiar with the command line tools for them then most of Docker should seem somewhat natural (though you should still read the docs!).

Docker logo

Docker Images and Containers

It is still important to know what Docker is and what the components of it are. Docker images are executables that bundle together all necessary components for an application or an environment. Docker containers are the runtime instances of images — they are images with a state.

Importantly, containers share the host machine’s OS system kernel and so don’t require an OS per application. As discrete processes containers take up only as much memory as necessary, making them very lightweight and fast to spin up to run.

Docker structure

Key Points

  • First key point. Brief Answer to questions.