A small script which helps you shrink size of Docker images.
Unfortunately Docker doesn't solve the problem of large images out of the box. Squashing images can help but it forces you to include extra cleanup commands. Sometimes this can be a headache.
The solution is to split responsibilities between Dockerfile.build and Dockerfile.
Dockerfile.build builds application artifacts. This can be anything, from a static website to a standalone application.
Dockerfile is an execution environment. Artifacts, from the previous image, are copied here. Development tools aren't included which allows you to create a ridiculously small image.
The example directory contains a sample use case. This is a React application which requires development tools during build time. Thanks to the script the final image is very lightweight:
| Image | Size |
|---|---|
| microcontainer-build (Dockerfile.build) | 266.4 MB |
| microcontainer (Dockerfile) | 5.271 MB |
- docker is installed;
Execute:
$ cd ./example
$ ../build.sh
$ docker run -p 80:80 microcontainer
...it's possible to define a custom name, tag and artifacts path, for example:
$ cd ./example
$ ../build.sh myproject 1.0 /workspace/.
$ docker run -p 80:80 myproject:1.0
...more information in the build.sh file.
Feel free to test it against your Dockerfile.build and Dockerfile.