A hands-on learning repository for Docker fundamentals. Every file is exhaustively commented to serve as a self-contained teaching document. Read any file in isolation and you will understand what it does, why it does it, and what would break if you changed it.
Before you begin, make sure you have the following installed:
| Tool | Version | Install |
|---|---|---|
| Docker Engine or Docker Desktop | 24.x or newer | https://docs.docker.com/get-docker/ |
| Python | 3.12 | https://www.python.org/downloads/ |
| Git | Any recent version | https://git-scm.com/ |
Windows / macOS: Docker Desktop includes the Docker Engine and Docker Compose. Linux: Install Docker Engine and Docker Compose as separate packages.
Work through the modules in numbered order. Each one builds on the concepts from the last.
| Module | What you will learn |
|---|---|
| 01-first-dockerfile | Write your first Dockerfile from scratch. Understand every instruction: FROM, WORKDIR, COPY, RUN, EXPOSE, CMD, HEALTHCHECK, and the non-root user pattern. |
| 02-image-layers | Understand Docker's layer cache. See exactly why instruction order is architectural rather than cosmetic, and how to arrange your Dockerfile to maximise cache hits and cut rebuild times. |
| 03-volumes | Persist data beyond the container lifecycle. Learn named volumes vs bind mounts, every docker volume command, how Docker initialises volumes from image contents, and when to choose each storage type. |
| 04-build-and-tag | Master the full image lifecycle: build, tag, list, remove, and prune. Learn semver and git-SHA tagging conventions and understand how tags map to registry push paths. |
| 05-run-flags | Run containers like a professional. Cover every important docker run flag: detach, port mapping, env vars, volumes, naming, restart policies, and resource limits. |
| 06-dockerignore | Understand the Docker build context and why .dockerignore is not optional. Learn to exclude secrets, large files, and cache directories — and how to measure the impact. |
Every docker command used across all modules, with a one-line description of when to reach for it.
# ── IMAGE COMMANDS ────────────────────────────────────────────────────────────
# Build an image from a Dockerfile in the current directory and name it
docker build -t <name>:<tag> .
# Build using a non-default Dockerfile name (e.g. Dockerfile.optimized)
docker build -f Dockerfile.optimized -t <name>:<tag> .
# List all images stored locally — shows REPOSITORY, TAG, IMAGE ID, CREATED, SIZE
docker image ls
# Remove a specific image by name:tag or by IMAGE ID
docker image rm <name>:<tag>
# Remove all dangling images (untagged layers left behind after rebuilds)
docker image prune
# Remove ALL unused images, not just dangling ones — use with caution
docker image prune -a
# Add an additional tag to an existing local image (does not copy — same layers)
docker tag <source>:<tag> <target>:<newtag>
# Inspect all metadata for an image as JSON (architecture, env vars, layers, etc.)
docker inspect <name>:<tag>
# ── VOLUME COMMANDS ───────────────────────────────────────────────────────────
# Create a named volume Docker will manage
docker volume create <name>
# List all volumes (named and anonymous)
docker volume ls
# Show full metadata for a volume (Mountpoint, CreatedAt, Labels)
docker volume inspect <name>
# Permanently delete a named volume and all its data
docker volume rm <name>
# Remove all volumes not currently mounted by any container
docker volume prune
# ── CONTAINER COMMANDS ────────────────────────────────────────────────────────
# Run a container in the foreground (your terminal is attached; Ctrl-C stops it)
docker run <name>:<tag>
# Run a container detached in the background; prints the container ID
docker run -d <name>:<tag>
# Map host port 8080 to container port 5000 (host:container)
docker run -p 8080:5000 <name>:<tag>
# Pass a single environment variable into the container
docker run -e MY_VAR=value <name>:<tag>
# Pass all variables from a file into the container
docker run --env-file sample.env <name>:<tag>
# Mount a named volume at a container path (Docker manages the host storage)
docker run -v <volume-name>:/container/path <name>:<tag>
# Bind-mount a host directory into the container (read-write)
docker run -v /host/path:/container/path <name>:<tag>
# Bind-mount a host directory into the container (read-only)
docker run -v /host/path:/container/path:ro <name>:<tag>
# Give the container a human-readable name you can use in other commands
docker run --name my-container <name>:<tag>
# Auto-remove the container when it exits (good for one-shot tasks)
docker run --rm <name>:<tag>
# Run with a restart policy so the container restarts on failure
docker run --restart on-failure <name>:<tag>
# Run with an interactive pseudo-TTY attached (great for debugging)
docker run -it <name>:<tag> /bin/bash
# Limit the container to half a CPU and 256 MB of RAM
docker run --cpus 0.5 --memory 256m <name>:<tag>
# List currently running containers
docker ps
# List ALL containers including stopped ones
docker ps -a
# Stop a running container gracefully (SIGTERM → wait → SIGKILL)
docker stop <name-or-id>
# Remove a stopped container
docker rm <name-or-id>
# Stream live log output from a container
docker logs -f <name-or-id>
# Execute an interactive shell inside a running container
docker exec -it <name-or-id> /bin/bash| Topic | Link |
|---|---|
| Dockerfile reference | https://docs.docker.com/reference/dockerfile/ |
docker build |
https://docs.docker.com/reference/cli/docker/buildx/build/ |
docker run |
https://docs.docker.com/reference/cli/docker/container/run/ |
| Image layer caching | https://docs.docker.com/build/cache/ |
.dockerignore |
https://docs.docker.com/reference/dockerfile/#dockerignore-file |
| HEALTHCHECK | https://docs.docker.com/reference/dockerfile/#healthcheck |
| Docker volumes | https://docs.docker.com/engine/storage/volumes/ |
| Bind mounts | https://docs.docker.com/engine/storage/bind-mounts/ |
docker image ls |
https://docs.docker.com/reference/cli/docker/image/ls/ |
| Restart policies | https://docs.docker.com/engine/containers/start-containers-automatically/ |
| Resource constraints | https://docs.docker.com/engine/containers/resource_constraints/ |