In each main DC we currently have exactly one mediawiki maintenance (mwmaint*) server but ideally we want to be able to have more than one per DC for migrations.
One defintion of the single "active" server is based on where the actual mw maint "crons" (now systemd timers) are running.
Then there is another one based on which webserver is currently hosting noc.wikimedia.org.
The latter already tries to avoid hardcoded host names by using a discovery record https://mwmaint.discovery.wmnet
but the former depends on on the active data center setting in the mw-config repo.
So we had a situation where one was switched and not the other.
This ticket is to make sure they are switching together in one way or another and also add the usual puppet code that warns people when they are on a non-active server.