As detailed here https://phabricator.wikimedia.org/T219652, osmdb.eqiad.wmnet will be changed to point at the osm.db.svc.eqiad.wmflabs.  For a brief time that will make those tables that aren’t always read-only also read-only while DNS updates.  Then the replica will be promoted to the master, and the rest of the steps should not cause any impact.