Build Your Own Docker: Introduction [0/2]

This is the introductory article in a series where we’ll build a toy Docker clone in Go.

Next article: Executing a process

Sections in this article:

• Introduction
• What we’ll build

Introduction

Docker is probably the most popular way to package and run applications in existence today. If you’ve used Docker, it’s likely that a lot of its inner workings are a mystery to you.

➜ docker run alpine echo "hello world!"
hello world!

^ What exactly happens when you run this? That’s the question this series will help you answer. We’ll walk through how Docker works, by attempting to build a small Docker clone ourselves.

What we’ll build

In this course, we’ll build a toy Docker clone that’s capable of pulling an image from docker.io and executing a command in it.

Along the way we’ll learn about:

• How Docker executes a program and keeps it isolated from the host system.
• What a Docker image contains, and how it is stored
• How Dockerfile caching works
• How Docker images are transmitted over the network, i.e. what happens when you execute docker pull

Ready for the first lesson?