Dockerfile Cheat Sheet

1. FROM: Specifies the base image to use for the build.
2. RUN: Runs a command during the build process.
3. COPY: Copies files or directories from the host machine to the container.
4. ENV: Sets an environment variable in the container.
5. EXPOSE: Exposes a port or ports to be used by the container.
6. ENTRYPOINT: Specifies the command to run when the container starts.
7. CMD: Specifies default arguments for the ENTRYPOINT command.
8. USER: Sets the user and group to run the container as.
9. WORKDIR: Sets the working directory for commands run in the container.
10. VOLUME: Creates a mount point for a volume in the container.

Example:

FROM alpine
RUN apk update && apk add python3
COPY myfile.txt /app
ENV MY_ENV_VAR=value
EXPOSE 8080
ENTRYPOINT ["python3"]
CMD ["app.py"]
USER 1001
WORKDIR /app
VOLUME /data

Note: Always try to use specific version of base images and package to avoid any unexpected behaviour.

Other cheat sheets and official doc

• https://kapeli.com/cheat_sheets/Dockerfile.docset/Contents/Resources/Documents/index
• https://docs.docker.com/engine/reference/builder/

Page last modified: 2024-03-08 14:39:17