About 3 weeks ago, the technical lead of one of Gitpod's self-hosted customers messaged me saying:

Hey Simon. I know we have to use Ubuntu for our images, but one of our teams uses a testing framework that only runs on CentOS.

Please help.

What had happened was they had conflated two facts about Gitpod:

1. when running a Gitpod installation, you must run Ubuntu on your Kubernetes nodes
2. the Gitpod workspace images use an Ubuntu image (currently buildpack-deps:focal) as the base

However, this doesn't mean that you MUST use Ubuntu. In fact, you can theoretically use any Linux distribution as your base image (except Alpine - see #3356).

Building a CentOS base image

In principal, this is just a question of copying the Ubuntu image and changing all the apt-get install commands for yum install and changing the package names where relevant.

Take a look at the Dockerfile to see how you could achieve this. There are quite a few packages in here which make it all work:

• bash-completion
• other Unix shells, such as Fish and ZSH
• development tools
• Git and Git LFS
• Docker and Docker Compose

It also creates a gitpod user with the user ID 33333 and grants it anonymous sudo access.

Using this in your project

Now we have a base image, we can use this in our project. This is as simple as defining a custom Docker image in your .gitpod.yml. Then you can create a .gitpod.Dockerfile like this:

FROM ghcr.io/mrsimonemms/gitpod-centos-base-image:latest

### Node.js ###
LABEL dazzle/layer=lang-node
LABEL dazzle/test=tests/lang-node.yaml
USER gitpod
ENV NODE_VERSION=16.13.0
ENV TRIGGER_REBUILD=1
RUN curl -fsSL https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.0/install.sh | PROFILE=/dev/null bash \
  && bash -c ". .nvm/nvm.sh \
    && nvm install $NODE_VERSION \
    && nvm alias default $NODE_VERSION \
    && npm install -g typescript yarn node-gyp" \
  && echo ". ~/.nvm/nvm-lazy.sh"  >> /home/gitpod/.bashrc.d/50-node
# above, we are adding the lazy nvm init to .bashrc, because one is executed on interactive shells, the other for non-interactive shells (e.g. plugin-host)
COPY --chown=gitpod:gitpod nvm-lazy.sh /home/gitpod/.nvm/nvm-lazy.sh
ENV PATH=$PATH:/home/gitpod/.nvm/versions/node/v${NODE_VERSION}/bin

USER gitpod

You will need to copy nvm-lazy.sh into your project. You could also use a cURL command to download it from GitHub, but I couldn't be bothered for a simple app.

Once you've done that, your workspace is ready for development in Gitpod

Further work

If you're having to use this for multiple projects, you will most probably want to create either a workspace-full equivalent (or whatever languages you want to support). Creating a standalone image and publishing it to your own Docker registry isn't covered here, but isn't any more difficult than creating a Docker image.

Resources

• CentOS Base Image: a Gitpod CentOS base image you can use yourselves
• CentOS Node Example: an example GitHub repository with a Node application

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Credits

Photo by Brett Jordan