Citrix: VM Hosting Server
This checks displays the hosting server on which a VM is currently running.
It is purely informative and always OK.
The citrix_farm.ps1 plugin must be installed on the controller, and
the Checkmk agent must be executed with Citrix Admin permissions
for this to work. Data for the hosts is collected on the controller and
given to the monitoring server as piggyback data.
One service is created for each controller.