I’m migrating an existing mastodon instance to a new server. It’s docker based, matodon v2.5.0.
The existing instance was:
- somewhat customised, using docker swarm not docker-compose
- has a significant number of users
- is essentially abandoned by its original admins, and the setup is undocumented
So I’m learning all the details on the job, not previously having installed mastodon, being a mastodon admin, nor even very familiar with docker.
Most people, as I understand it, migrate by getting the new server working following the vanilla instructions and a blank database, then migrating the database during a single block of downtime.
What I’d like to be able to do is run the new instance on a temporary domain with a snapshot of the existing instance’s database, to verify I’ve got it all working before I switch off the old one and transfer the domain.
But, I’m led to understand I may create some sort of federation “mess” if I do that naively. So:
- what can I do to avoid that?
- how would I clean up the mess if I did manage to slip up?