Overview

If you’re a programmer, do any of the following situations apply to you?

• You want to run an app (or toolchain) your machine, but you don’t want to install it.

• You want to connect to other services, like database servers, but you don’t want to install them on your own machine (or maybe you want to test against multiple versions).

• You want to share your app with others, but it only runs in certain environments, or it has dependencies that must be installed first to be able to run.

• You want to deploy your app to a server somewhere where other users can connect to it, but you don’t want to have to manage the installation of your app and its dependencies on the server.

• You want to be confident that what you package up will run the same way on each machine it runs on.

Enter Docker

These are all scenarios that Docker can help you with.

Docker refers to a technology, tooling, and an ecosysem that makes it possible to package up software, share it with others, and run it in a special, isolated environment called a container on any supported operating system.

The key to unleashing Docker’s power is understanding how to write a Dockerfile. If you’ve seen Docker commands or Dockerfile instructions and they seemed a bit arcane to you, keep reading.

Is this for you?

In this guide, you’ll learn how write Dockerfiles so that you can containerize just about anything. Unlike most other guides that focus on learning Docker first before diving into writing a Dockerfile, we’re going to invert that model.

Since you’re a programmer, we’re going to focus right off the bat on writing Dockerfiles coming from a programmer perspective. We’re going to build on a series of examples that will develop your knowledge and confidence in writing Dockerfiles.

You will become familiar with Docker as you build on your Dockerfile skills. If you choose to work your way through the entire guide, you’ll learn best practices for creating industrial strength Dockerfiles, like the ones used for official images on Docker Hub, and you’ll have the confidence to apply your skills to containerize anything for fun and profit.

What’s next?

We’re going to start from ground zero and the only assumptions up front are that you already have:

• basic familiarity with using the command line in a terminal
• basic understanding of file systems and networking
• access to a programmer / text editor (not a formatting word processor), like nano, vim, or Visual Studio Code.

The journey begins with the first step, so let’s dive in with Getting Started.