Docker Alpine Ruby

The smallest Docker image with Alphine 3.4 and Ruby 2.3. The image size is only 29 MB!

Alpine Linux is a Linux distribution built around musl libc and BusyBox. The image is 5 MB in size and has access to a package repository that is much more complete than other BusyBox based images.

Usage

Install Docker.

To build an image from the Dockerfile run:

$ make build
$ docker images

REPOSITORY           TAG                 IMAGE ID            CREATED             SIZE
docker-alpine-ruby   latest              1fa6b8033680        7 seconds ago       31.72 MB
alpine               3.4                 4e38e38c8ce0        8 weeks ago         4.799 MB

Now you can test your image by running a command:

$ make execute COMMAND='ruby -v'

ruby 2.3.1p112 (2016-04-26 revision 54768) [x86_64-linux-musl]

Or you can connect in console:

$ make sh

/ # ruby -v
ruby 2.3.1p112 (2016-04-26 revision 54768) [x86_64-linux-musl]

To reduce the size of the image:

$ make flatten

REPOSITORY           TAG                 IMAGE ID            CREATED             SIZE
docker-alpine-ruby   latest              aaad6c488c79        8 seconds ago       29.24 MB
<none>               <none>              1fa6b8033680        3 minutes ago       31.93 MB
alpine               3.4                 4e38e38c8ce0        8 weeks ago         4.799 MB

Remove containers and images:

$ docker ps -a

CONTAINER ID        IMAGE               COMMAND             CREATED             STATUS              PORTS               NAMES
c20ce0f07d47        1fa6b8033680        "/bin/sh"           2 minutes ago       Created                                 docker-alpine-ruby

$ make remove_all_containers
$ make remove_all_images

Native extensions

Uncomment the following lines from the Dockerfile if you use these gems with native extensions and other dependencies:

• puma, oj, byebug

RUN apk --no-cache add make gcc libc-dev

• nokogiri

RUN apk --no-cache add make libxml2 libxslt-dev g++

• rb-readline

RUN apk --no-cache add ncurses

• mysql2

RUN apk --no-cache add mysql-dev

• ffi

RUN apk --no-cache add libffi-dev

• etc.

Useful links

• Reduce docker image size.
• Difference between save and export in Docker.
• A faster bundle install.
• How to cache bundle install with Docker.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/exAspArk/docker-alpine-ruby.

License

The gem is available as open source under the terms of the MIT License.