Overriding configuration fields during omnibus install

I’ve been running GitLab on my home lab network for a while now and I’m experimenting with using the Omnibus for a work-based AWS exploration – SaaS not an option because vpn/tunnels/subgit.

The documentation reads as though there is some way to override gitlab.rb fields during the initial apt install either the way you can with docker compose or by pre-providing your own gitlab.rb file (in particular I’d like to point the database at a waiting RDS instance, although that’s a separate issue)

Is there a mechanism for this?