Have no idea how this happened but so far it only happened to 1 agent. The following symptoms are noticed:
- In Discovered Inventory (filtered to Windows Server) the server shows up as green checkmark, diagram view shows its components, performance view shows the discovered objects but no performance data gets returned.
- In the console's administration pane, the server is nowhere to be found in Agent Managed (where it should be), Agentless Managed and Pending Management.
- Attempting to manually install the agent through the Discovery Wizard and manually entering the server name to be discovered returns no servers discovered. (It's a domain-joined server so it should show up)
- Logging in to the server and checking there directly shows the Microsoft Monitoring Agent installed and configured to home to the management group, but the event logs show that it cannot authenticate to the management group.
- Checking from management server side I see event ID 20000 for 2 servers. (One of them is the server this post is about, the other one seems a slightly different issue so I won't get into it yet).
- Running a generic report to try to get historic performance for the affected server data shows the latest data was about 2 months ago as of time of writing.
The above leads me to think that this server did exist as an agent (99% sure it was also Remotely Managed) until 2 months ago. While finding a root cause falls onto me (I'll keep looking but since this is a VM I have a sneaking suspicion about cloning + renaming shenanigans, have to check with my colleagues first) but I would appreciate any help on HOW to recover from this scenario for this agent.
