Smallest Ruby Image for Docker

A Ruby image with most common build dependencies installed to compile native GEMs. It is only 329.7 MB and is optimized for minimum overhead, while including all required dependencies for common GEMs like nokogiri, curb or mysql2. The base image is a minimal Ubuntu 14.04 which makes it easy and flexible to install more exotic Ruby apps.

ruby:2.3 | 285.1 MB

Image Name

firedev/ruby:2.3

Quick Usage

$ docker run -it firedev/ruby:2.3 ruby -e 'puts RUBY_VERSION'
2.3.3

Image Size

This image is only 285.1 MB and contains most common build dependencies. Additionally, the image is based on a normal Ubuntu 14.04 base image and therefore most of your applications should install without problems.

We have looked at more exotic Linux distributions with even smaller base images. But when installing common dependencies required for Ruby GEMs, these images result in similar sizes, sometimes even larger. And having an Ubuntu based image makes life often easier as documentation and common knowledge is far better.

Comparison to Similar Images

Similar images are more than double the size of this image. We have researched popular Ruby images for Docker:

Semi-official Ruby image
ruby:2.2.0                  774.7 MB

Without build dependencies (native GEMs can't be compiled)
ruby:2.2.0-slim             299.3 MB

Atlas Health (only minimal build dependencies, libcurl & libxml)
atlashealth/ruby            347.2 MB

The semi-official Ruby-slim image is only 30 MB smaller but has no build dependencies included at all and hence all GEMs with native extension will fail to install. In contrast the minimal CloudGear Ruby image is only 222.7 MB.

What's Included in the Image?

The image comes in multiple variations and versions. For detailed information check the corresponding Dockerfiles in the Github repository.

The image includes the specified Ruby version, the latest Rubygems and Bundler packages and common build dependencies. It is based on the cloudgear/build-deps image, check it out for more details.

Image name: only version tags without any suffix, e.g. firedev/ruby:2.3

Tested GEMs

Most common GEMs with native extensions install fine, we have tested following GEMs:

sqlite
mysql2
postgres (pg)
nokogiri
oj (json using native extension)
curb
unicorn
puma

Please help us to test and support other GEMs with native extensions and report your problems as Github issues. Thanks.

Usage

Run IRB

$ docker run -it firedev/ruby:2.3 irb

Run a single Ruby command

$ docker run firedev/ruby:2.3 ruby -e 'puts "A simple Ruby demo"'
A simple Ruby demo

Dockerfile

To build a custom image with some GEMs installed, create a Dockerfile:

FROM cloudgear/ruby:2.3

RUN gem install haml

ENTRYPOINT ["haml"]

Supported Tags

The image comes with the latest Ruby versions 2.3

All variations and versions

firedev/ruby:2.3

Contributing

We welcome contributions like new features, fixes, version bumps and other optimizations. Please create a pull request or in case of problems or questions file a Github issue.

The image is configured as a Docker Automated Build and gets built and pushed to the Docker registry for every push.

License

A product by CloudGear.