How do the geo distributed secondaries work? How do they sync?
Also, is there anycasting?
The geo sync updates are handled with distributed keys over internal api, here is the documentation for powerdns around it: https://doc.powerdns.com/authoritative/dnsupdate.html#dnsupd... so the updates are pushed and updated to primaries if the update is done over DNS and if done via API there is a normal replication function.
right now there is no anycast available, possible in the future
Thanks for the answer. I use DB replicas (so all dns servers have a common backend), but only one accepts writes.
I still can not figure out any economical way to roll out anycast.