windows_exporter/docs/runbooks/windowshypervwmiunhealthy.md

title

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WindowsHyperVWMIUnhealthy

Meaning

The Hyper-V WMI namespace root/virtualization/v2 on the host has not answered a minimal query for ten minutes. The alert needs the hyperv collector with its wmi_health subcollector. While the namespace is broken, the virtual machine, replication and virtual hard disk metrics that come from WMI are missing, so the other Hyper-V alerts cannot fire.

Impact

Management tools such as Hyper-V Manager, Failover Cluster Manager and System Center cannot manage the virtual machines on the host. Backups that use the Hyper-V VSS writer fail. The virtual machines themselves usually keep running.

Diagnosis

1. Inspect windows_hyperv_wmi_health and windows_exporter_collector_success{collector="hyperv"} for the host.

2. On the host, test the namespace and the management service:

   Get-CimInstance -Namespace root/virtualization/v2 -ClassName Msvm_ComputerSystem | Select-Object -First 1
   Get-Service vmms, vmcompute, winmgmt
   winmgmt /verifyrepository
   

3. Check the System and the Microsoft-Windows-Hyper-V-VMMS logs for errors of the Virtual Machine Management service, and the WMI-Activity log for provider failures. A stuck vmms process or a corrupt WMI repository are the usual causes.

Mitigation

Restart the Virtual Machine Management service with Restart-Service vmms; running virtual machines are not affected. If the repository is inconsistent, run winmgmt /salvagerepository, and register the Hyper-V provider again with mofcomp of the Hyper-V MOF files only when Microsoft support advises it. Plan a restart of the host if the service cannot be recovered. Confirm the health metric returns to 1 and the Hyper-V metrics appear again.