Official Repository

Last pushed: 2 days ago
Short Description
Ruby is a dynamic, reflective, object-oriented, general-purpose, open-source programming language.
Full Description

Supported tags and respective Dockerfile links

For more information about this image and its history, please see the relevant manifest file (library/ruby). This image is updated via pull requests to the docker-library/official-images GitHub repo.

For detailed information about the virtual/transfer sizes and individual layers of each of the above supported tags, please see the repos/ruby/ file in the docker-library/repo-info GitHub repo.

What is Ruby?

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.

How to use this image

Create a Dockerfile in your Ruby app project

FROM ruby:2.1-onbuild
CMD ["./your-daemon-or-script.rb"]

Put this file in the root of your app, next to the Gemfile.

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

Generate a Gemfile.lock

The 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 Gemfile:

$ docker run --rm -v "$PWD":/usr/src/app -w /usr/src/app ruby:2.1 bundle install

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 ruby:2.1 ruby your-daemon-or-script.rb


By default, Ruby inherits the locale of the environment in which it is run. For most users running Ruby on their desktop systems, that means it's likely using some variation of *.UTF-8 (en_US.UTF-8, etc). In Docker however, the default locale is C, which can have unexpected results. If your application needs to interact with UTF-8, it is recommended that you explicitly adjust the locale of your image/container via -e LANG=C.UTF-8 or ENV LANG C.UTF-8.

Image Variants

The ruby 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 tag is based off of buildpack-deps. buildpack-deps is designed for the average user of docker who has many images on their system. It, by design, has a large number of extremely common Debian packages. This reduces the number of packages that images that derive from it need to install, thus reducing the overall size of all images on your system.


This image does not contain the common packages contained in the default tag and only contains the minimal packages needed to run ruby. Unless you are working in an environment where only the ruby image will be deployed and you have space constraints, we highly recommend using the default image of this repository.


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 git or 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).


This image makes building derivative images easier. For most use cases, creating a Dockerfile in the base of your project directory with the line FROM ruby:onbuild will be enough to create a stand-alone image for your project.

While the 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 docker/docker#5714, docker/docker#8240, docker/docker#11917).

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 onbuild variant 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-ONBUILD steps).


View license information for the software contained in this image.

Supported Docker versions

This image is officially supported on Docker version 17.03.0-ce.

Support for older versions (down to 1.6) is provided on a best-effort basis.

Please see the Docker installation documentation for details on how to upgrade your Docker daemon.

User Feedback


If you have any problems with or questions about this image, please contact us through a GitHub issue. If the issue is related to a CVE, please check for a cve-tracker issue on the official-images repository first.

You can also reach many of the official image maintainers via the #docker-library IRC channel on Freenode.


You are invited to contribute new features, fixes, or updates, large or small; we are always thrilled to receive pull requests, and do our best to process them as fast as we can.

Before you start to code, we recommend discussing your plans through a GitHub issue, especially for more ambitious contributions. This gives other contributors a chance to point you in the right direction, give you feedback on your design, and help you find out if someone else is working on the same thing.


Documentation for this image is stored in the ruby/ directory of the docker-library/docs GitHub repo. Be sure to familiarize yourself with the repository's file before attempting a pull request.

Docker Pull Command

Comments (28)
7 days ago


Yes, you need to add your own JS runtime. If you came to this image from the rails image, which is now deprecated, you may find this inconvenient, but it's actually good design. Now we can choose our own components for rails and build them on top of the ruby image.

Concerning 2.4, you should know that right now, there's a bug in 2.4 that causes requests to randomly fail because of segmentation faults ( if you use MongoDB. For that reason, because most of my projects use MongoDB, I stick with Ruby 2.3 until 2.4.1 is released. They've already fixed the bug and they plan to include the fix in 2.4.1.

16 days ago

I am using ruby:2.4.0-onbuild in order to deploy a simple rails 5 app and just noticed that nodejs is not included as you can see below when I start my docker container:

/usr/local/lib/ruby/gems/2.4.0/gems/bundler-1.14.6/lib/bundler/runtime.rb:94:in `rescue in block (2 levels) in require': There was an error while trying to load the gem 'uglifier'. (Bundler::GemRequireError)
Gem Load Error is: Could not find a JavaScript runtime. See for a list of available runtimes.

do I understand this correctly that I should add nodejs (among other requirements for rails) in my own image which is based on your ruby image?

2 months ago

Anyone facing issue with latest ruby

ERROR: SSL verification error at depth 0: certificate is not yet valid (9)

ERROR: SSL verification error at depth 0: certificate is not yet valid (9)

ERROR: SSL verification error at depth 0: certificate is not yet valid (9)

ERROR: Could not find a valid gem 'bundler' (>= 0), here is why:
Unable to download data from - SSL_connect returned=1 errno=0 state=error: certificate verify failed (
ERROR: SSL verification error at depth 0: certificate is not yet valid (9)

3 months ago

when will ruby 2.4.0 image be available?

4 months ago

Now, I can run docker pull ruby:2.3.2. Thanks!

4 months ago

Ruby 2.3.2 is released at 2016-11-15.
And GitHub repository is updated at 9b3ffd5.

But this Docker Hub repository is not updated yet. Please update!

a year ago

Is 717MB really the base size for this? it seems insanely large can you try cleaning this up a little please.

2 years ago

Fought trouble with encoding for hours until I saw @maccman's comment below. For future googlers: see his post to set UTF-8 encoding:

2 years ago

Check my extremely slim ruby image out: frolvlad/alpine-ruby

This official image is 264MB in slim version!

BTW, there is no issue with encoding in my ruby image, it uses UTF-8 by default.

2 years ago

why do they make these images with BUNDLE FREEZE option!? damm