Docker for Mere Mortals

"It works on my machine" is the most expensive sentence in software. Docker fixes it by shipping the machine with the software: your app plus everything it needs, packed into a container that runs the same everywhere.

No CS degree required. Ideas first, then commands you can type.

What this guide covers

What Docker is — containers vs. virtual machines, and why the distinction matters
Installing Docker — on Linux, Mac, and Windows
Your first container — docker run, dissected piece by piece
Images vs. containers — the single distinction that unlocks everything
The Dockerfile — writing your own image, layer by layer
Volumes and data — keeping data alive after the container dies
Ports and networking — letting the world (or just you) in
Docker Compose — multi-container apps in one file
Registries — where images live (Docker Hub and friends)
Day-to-day Docker — the commands you'll actually use
Troubleshooting — the errors everyone hits

What it doesn't cover

Kubernetes (that's orchestration — running containers across many machines — and it's a guide of its own), Swarm, building production pipelines, or Docker's internals. This guide is about understanding and using Docker on your own machines.

How to use this guide

Commands are meant to be typed. Check: blocks show what success looks like. Careful: marks anything destructive.

A note on verification

Image builds, volume and network management, and Compose file validation were verified against Docker 29.1.3 and Compose v5.6.0. Container execution examples (run output, logs, exec sessions) show typical output — the verification sandbox blocks starting containers, so confirm those on your own machine. Anything shown as typical rather than measured is labeled.

Chapters

Written to the nine-point writing standard shared by every guide in this series.