I ran into an issue recently where I needed to register the IP of a DAG. I discovered this wasn’t well documented and it took a while to figure out how to get it registered.
I first tried running ipconfig /registerdns on the primary active manager. To find the primary active manager you must run
get-databaseavailabilitygroup <name> -status | select name,primaryactivemanager
But that did not work. What does work is running,
cluster . res "Cluster Name" /registerdns
on any of the cluster nodes.
The DAG will attempt to register on its own at some random time within 2 hours of midnight.
Hope it helps.