you can use nagios to monitor your infrastructure of basic IT resources.

you should first define a host to be monitored then use the define service to do the action,it’s the OO thinking mind.

taking the NT platform as a example,install the NSClient++ plugin as agent to the hosts you want to monitor.

define host{
        use             windows-server  ; Inherit default values from a template
        host_name       host1  ; The name we're giving to this host
        alias           COS Security Server     ; A longer name associated with the host
        address   ; IP address of the host

define service{
        use                     generic-service
        host_name               host1
        service_description     NSClient++ Version
        check_command           check_nt!CLIENTVERSION


check_command is the bin action of monitoring the resource,there are lots of monitor action in $nagios/bin and you add