I’m running the mastodon stack in docker via a compose file. It was straight forward. Follow the instructions to the letter and it will work.
I will say that it is in your best interest to have an automated update process happen, either manually (via cron) multiple times a day or have some kind of orchestration layer that manages updating the component images once they are released. Mastodon has had some nasty 0 day bugs that involved account and server takeover that had to be fixed immediately, and you don’t want to lag very far behind in those cases.
Edit:
Docker compose from their repo:
https://github.com/mastodon/mastodon/blob/main/docker-compose.yml
Seems like this could be killer for building a multi-Turing Pi rack mount case.