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Engineer ← All courses
Beginner·9 lessons·101 min
Docker Fundamentals
Docker from zero, correct for the current release. Containers and images, Dockerfiles, layers and the build cache, volumes, networking, and Compose — with the traps that most tutorials are still teaching wrong.
Written and verified against
- Docker Engine
- 29.7.2
- Docker Compose
- v5.5.0
- Buildx
- v0.36.1
- BuildKit
- v0.32.2
- Dockerfile frontend
- 1.26.0
- Docker Desktop
- 4.88.1
Checked 28 August 2026. Official docs: docs.docker.com ↗
- 01What Docker IsThe CLI, the daemon, containerd, and the difference between an image and a container. 11 min
- 02Running ContainersThe flags that make up most of what anyone types, and why containers exit. 11 min
- 03Images and RegistriesReading an image name, why `latest` is not the latest, and choosing a base. 11 min
- 04Your First DockerfileBuilding your own image, and CMD versus ENTRYPOINT. 11 min
- 05Layers and the Build CacheWhy instruction order is a performance decision, and why deleting a file does not shrink an image. 11 min
- 06Volumes and DataWhere state goes when the container is deleted — and the volume that quietly fills your disk. 11 min
- 07NetworkingPublishing ports, and the one networking fact that makes containers find each other. 11 min
- 08ComposeOne file instead of eleven flags — and why the CLI jumped from v2 to v5. 11 min
- 09Debugging and CleanupExit code 137, the commands that answer which question, and reclaiming the disk. 13 min