I posting a Workaround for a issue I found and notice that other people running into. So far I not seen or found a root cause or a fix. But this work around is the best I have discovered and better than rebooting the Hyper V host to resolve the issue.
Link to the Article on Tech Net:
URL: http://social.technet.microsoft.com/forums/en-US/virtualmachinemanager/thread/ac48fd59-3de9-4191-8466-25bedee3f5b1
Workaround:
Though I have not found the root cause, but I did find something of a workaround that quickly brings the Hyper V host back to a functional state.
When I see the error of :
Error (2912)
An internal error has occurred trying to contact an agent on the servername.domain.com server.
(No more threads can be created in the system (0x800700A4))
Recommended Action
Ensure the agent is installed and running. Ensure the WS-Management service is installed and running, then restart the agent.
I go to Services and Restart the "Windows Management Instrumentation" Service. Restarting this services also restarts the following services: (if they are on your server)
- Hyper V Virtual Machine Management
- Virtual Machine Manager Agent
- Hyper-V Image Management Service
- Hyper-V Networking Management Service
- IP Helper
- EMC PowerPath Service 5.1.2
- SMS Agent Host
Due to the type of services that are also restarted when doing this, and if the Hyper V host is in production. I would suggest doing this with caution and sending a user awareness notification for the temporary outage. Though the outage is small depending on how long it takes for certain services to start.
Because the Hyper-V Image Management Service is restarted. Users will not be able remote control a virtual machine or may be kicked off the VM remote control session. And if you are doing this while TS into the Hyper V host server, you may lose TS connectivity momentarily.