Check manual page of esx_vsphere_hostsystem.maintenance
VMWare ESX Host System: Maintenance State
This check queries the maintenance State of an ESX host
system via the vsphere agent and returns:
OK if the ESX host has the same sate since the last service detection
CRIT if the state has changed.
The behavior can be changed by a Wato rule to force Maintenance mode or not.
See "Monitoring VMWare ESX with Check_MK" in the online documentation
On each ESX host one check is generated.