Supported tags and respective
Where to file issues:
the Docker Community
Supported Docker versions:
the latest release (down to 1.6 on a best-effort basis)
What is JRuby?
Ruby is a dynamic, reflective, object-oriented, general-purpose, open-source programming language. According to its authors, Ruby was influenced by Perl, Smalltalk, Eiffel, Ada, and Lisp. It supports multiple programming paradigms, including functional, object-oriented, and imperative. It also has a dynamic type system and automatic memory management.
JRuby leverages the robustness and speed of the JVM while providing the same Ruby that you already know and love. With JRuby you are able to take advantage of real native threads, enhanced garbage collection, and even import and use java libraries.
How to use this image
Dockerfile in your Ruby app project
FROM jruby:1.7-onbuild CMD ["./your-daemon-or-script.rb"]
Put this file in the root of your app, next to the
This image includes multiple
ONBUILD triggers which should be all you need to bootstrap most applications. The build will
COPY . /usr/src/app and
RUN bundle install.
You can then build and run the Ruby image:
$ docker build -t my-ruby-app . $ docker run -it --name my-running-script my-ruby-app
onbuild tag expects a
Gemfile.lock in your app directory. This
docker run will help you generate one. Run it in the root of your app, next to the
$ docker run --rm -v "$PWD":/usr/src/app -w /usr/src/app jruby:1.7 bundle install --system
Run a single Ruby script
For many simple, single file projects, you may find it inconvenient to write a complete
Dockerfile. In such cases, you can run a Ruby script by using the Ruby Docker image directly:
$ docker run -it --rm --name my-running-script -v "$PWD":/usr/src/myapp -w /usr/src/myapp jruby:1.7 jruby your-daemon-or-script.rb
amd64/jruby images come in many flavors, each designed for a specific use case.
This is the defacto image. If you are unsure about what your needs are, you probably want to use this one. It is designed to be used both as a throw away container (mount your source code and start the container to start your app), as well as the base to build other images off of.
This image is based on the popular Alpine Linux project, available in the
alpine official image. Alpine Linux is much smaller than most distribution base images (~5MB), and thus leads to much slimmer images in general.
This variant is highly recommended when final image size being as small as possible is desired. The main caveat to note is that it does use musl libc instead of glibc and friends, so certain software might run into issues depending on the depth of their libc requirements. However, most software doesn't have an issue with this, so this variant is usually a very safe choice. See this Hacker News comment thread for more discussion of the issues that might arise and some pro/con comparisons of using Alpine-based images.
To minimize image size, it's uncommon for additional related tools (such as
bash) to be included in Alpine-based images. Using this image as a base, add the things you need in your own Dockerfile (see the
alpine image description for examples of how to install packages if you are unfamiliar).
ONBUILD image variants are deprecated, and their usage is discouraged. For more details, see docker-library/official-images#2076.
onbuild variant is really useful for "getting off the ground running" (zero to Dockerized in a short period of time), it's not recommended for long-term usage within a project due to the lack of control over when the
ONBUILD triggers fire (see also
Once you've got a handle on how your project functions within Docker, you'll probably want to adjust your
Dockerfile to inherit from a non-
onbuild variant and copy the commands from the
Dockerfile (moving the
ONBUILD lines to the end and removing the
ONBUILD keywords) into your own file so that you have tighter control over them and more transparency for yourself and others looking at your
Dockerfile as to what it does. This also makes it easier to add additional requirements as time goes on (such as installing more packages before performing the previously-
View license information for the software contained in this image.