Check ESX is a plugin developed to be used primarily with op5 Monitor, but which can also be used in Nagios installations to monitor VMware ESX and vSphere servers. You can monitor either a single ESX(i)/vSphere server or a VMware VirtualCenter/vCenter Server and individual virtual machines. If you have a VMware cluster, you should monitor the data center (VMware VirtualCenter/vCenter Server), and not the ESX/vSphere servers themselves.
