midDocker
What is the purpose of the '.dockerignore' file?
Updated Apr 28, 2026
Short answer
To exclude files and directories from the build context, speeding up builds and reducing image size.
Deep explanation
Modern Docker workflows focus on optimization. Multi-stage builds allow you to use a heavy build environment (with compilers and tools) but only copy the final binary into a slim production image (like Alpine).
Real-world example
Running a WordPress site with separate containers for PHP-FPM, Nginx, and MySQL locally.
Common mistakes
- Storing sensitive passwords in plain text within the Dockerfile or environment variables.
Follow-up questions
- How does Docker networking work by default?