In Microsoft Platform, there is a driver version 1.1.2.8 where we can monitor both the server from the TCP/IP and the ILO Management Interface via SNMP in order to see the HP Parameters (Physical Health Status of the server), We are looking for a driver version having the same concept in Linux Platform?
Hardware monitoring is a possibility for known agents (HP/DELL) as Phil recalls above. That's all polled via SNMP.
One more thing worth considering is that in terms of iLO/iDrac, most of the networks scenarios I've come across would keep that traffic in O.O.B., i.e. lights-out management completely separated from your standard polling traffic - this might play a part in your architecture.