Check manual page of esx_vsphere_vm.running_on
Virtual Machine under ESX: Hostsystem the VM is running on
This check provices information about the hostsystem where the VM is running on.
The check returns OK, unless the hostsystem is missing.
In this case it returns UNKNOWN.
See "Monitoring VMWare ESX with Check_MK" in the online documentation as well.
On each VM one check is generated.