We have an AlwaysOn Availability Group with 5 replicas. It's been running for over a year, and has had no problems. It seems healthy, by every check we can devise. We have practiced graceful failovers multiple times, without any trouble.
However, when setting up a monitoring tool, the new tool could not see our WSFC details. After some digging in the tool, it turns out the tool relies on sys.dm_hadr_instance_node_map to build its map of our setup. And, this DMV returns no rows in our production environment.
We have a very similar (I would have said identical, but it can't be) setup in dev/test, and everything is working as expected. The monitoring tool works great in dev/test, and sys.dm_hadr_instance_node_map returns the expected results.
I'm looking for clues as to why the result set would be empty. What have I missed?
Thanks!