Difficulty: beginner
Estimated Time: 5 minutes

Welcome to my short introduction to Docker for absolute newbees. I want to provide you with a guided environment in which you can play with Docker without have to install anything. Thanks to Katacode, you are up and running in seconds.

A note about the Katacoda: refreshing the page restarts your environment. So, if you're stuck, just hit refresh and start over again. If you accidentally hit refresh.... I'm sorry ;-)


You've completed this Docker introduction. You can continue with Docker Compose.

Install Docker Desktop.

Or search Katacode.com for more Docker tutorials.

Docker Introduction

Step 1 of 6

What is Docker?

To be short: Docker is a container runtime.

The long answer is: Docker is a tool designed to make it easier to create, deploy, and run applications by using containers. Containers allow a developer to package up an application with all of the parts it needs, such as libraries and other dependencies, and ship it all out as one package. By doing so, thanks to the container, the developer can rest assured that the application will run on any other Linux machine regardless of any customized settings that machine might have that could differ from the machine used for writing and testing the code.

The advantages of containers are numerous. To name a few eye-catchers:

  • create an immutable deployment unit that is exactly the same on every environment you deploy it (dev, test, production)
  • No more it-works-on-my-machine-nightmares
  • relief ops from installing the application over and over again
  • easy rolling upgrades
  • easy rollback to previous versions of your application (images are tagged, use them as versions)
  • easier debugging. If some production container version has a bug, spin it up locally and fix it!

So, head on to the next step and start you first container.