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Learn Docker by using it: run containers, publish ports, keep data in volumes, write Dockerfiles that build fast and small, connect services on networks, and run a whole app with Docker Compose. Every example runs in a pretend Docker right in the page, with real commands and realistic output, so you can experiment freely. Diagrams and a quick knowledge check every day.

  • 12 days
  • ~30 min / day
  • Intermediate
  • Free account required
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Start Day 1

The big picture

Everything you'll cover, and how it fits together.

Mind map · click a dot to fold, drag to pan

Day by day

Go at your own pace. Your progress is remembered on this device.

  1. 1
    Day 1Up next 30 min

    Containers: The Big Idea

    Why containers exist, images vs containers, and your first docker run.

    ContainersImagesdocker run
  2. 2
    Day 2 30 min

    Images & Tags

    Pull images, read their names and tags, and choose small variants.

    pullTagsRegistries
  3. 3
    Day 3 30 min

    Running Containers

    The container lifecycle: detached, named, logs, exit codes and cleanup.

    LifecyclelogsExit codes
  4. 4
    Day 4 30 min

    Inside a Container

    Open a shell in a container, look around, and pass in settings.

    exec -itEnv varsinspect
  5. 5
    Day 5 30 min

    Ports

    Publish container ports so you can reach the apps inside.

    -plocalhostConflicts
  6. 6
    Day 6 30 min

    Volumes & Bind Mounts

    Keep data when containers go away, and share folders with them.

    VolumesBind mountsPersistence
  7. 7
    Day 7 30 min

    Your First Dockerfile

    Package a website and a Python app as your own images.

    DockerfilebuildCMD
  8. 8
    Day 8 30 min

    Layers & Fast Builds

    How the build cache works, and Dockerfiles that build fast and small.

    LayersCache.dockerignore
  9. 9
    Day 9 30 min

    Configuration & Security

    Configure images with environment variables, keep secrets out, and drop root.

    ENV & ARGSecretsUSER
  10. 10
    Day 10 30 min

    Networks

    Let containers find each other by name on their own network.

    BridgeDNSMulti-container
  11. 11
    Day 11 30 min

    Docker Compose

    Describe a whole app in compose.yaml and run it with one command.

    compose.yamlup & downServices
  12. 12
    Day 12 30 min

    Project: A Three-Service App

    Ship a website, API and cache with multi-stage builds and Compose.

    Multi-stageHealthchecksScaling