Docker Dockerfile contents ordering
Remarks
- Base image declaration (
FROM) - Metadata (e.g.
MAINTAINER,LABEL) - Installing system dependencies (e.g.
apt-get install,apk add) - Copying app dependencies file (e.g.
bower.json,package.json,build.gradle,requirements.txt) - Installing app dependencies (e.g.
npm install,pip install) - Copying entire code base
- Setting up default runtime configs (e.g.
CMD,ENTRYPOINT,ENV,EXPOSE)
These orderings are made for optimizing build time using Docker's built-in caching mechanism.
Rule of thumbs:
Parts that change often (e.g. codebase) should be placed near bottom of Dockerfile, and vice-versa. Parts that rarely change (e.g. dependencies) should be placed at top.
