You can deploy Docker images based on Ubuntu or Debian as long as they run a legitimate application or service process. What our Fair Use Policy prohibits is using Railway as a virtual desktop or VNC environment, so deploying a bare OS image just to get an interactive shell or remote desktop is not permitted, but using an Ubuntu-based image as the foundation for running your application (like an agent) is fine.

Okay great, and what about templates. Can i create those for ubuntu or debian?

Yes, you can create templates using Ubuntu or Debian-based Docker images, as long as the template runs a legitimate application or service. The same fair use rules apply: templates that just provide a bare OS shell or VNC environment are not permitted, but packaging your agent or application on top of an Ubuntu/Debian base image into a template is fine. You can create and publish templates from your workspace templates page.