Building Container Images: Best Practices

A Docker Labspace that teaches how to build production-grade container images using Dockerfile best practices.

What You'll Learn

• How Docker images are composed of layers and why layer order matters
• Structuring Dockerfiles for fast, incremental builds using the layer cache
• Writing a .dockerignore and running containers as a non-root user
• Reducing image size dramatically with multi-stage builds
• Choosing the right base image (slim, alpine, distroless)
• Safely injecting secrets at build time using --mount=type=secret

Launch the Labspace

To launch the Labspace, run the following command:

docker compose -f oci://dockersamples/labspace-building-images up -d

And then open your browser to http://localhost:3030.

Using the Docker Desktop extension

If you have the Labspace extension installed (docker extension install dockersamples/labspace-extension if not), you can also click this link to launch the Labspace.

Contributing

If you find something wrong or something that needs to be updated, feel free to submit a PR. If you want to make a larger change, feel free to fork the repo into your own repository.

Important note: If you fork it, you will need to update the GHA workflow to point to your own Hub repo.

1. Clone this repo

2. Start the Labspace in content development mode:

   # On Mac/Linux
   CONTENT_PATH=$PWD docker compose up --watch
   
   # On Windows with PowerShell
   $Env:CONTENT_PATH = (Get-Location).Path; docker compose up --watch

3. Open the Labspace at http://dockerlabs.xyz.

4. Make the necessary changes and validate they appear as you expect in the Labspace

   Be sure to check out the docs for additional information and guidelines.