I have a two node Red Hat Cluster with HP Proliant servers.
This server has an HP iLO3 for Out-of-band management.
The fence_ilo agent works with iLO and iLO2.
Fence Device and Agent Information for Red Hat Enterprise Linux
You will need to use fence_ipmplan agent with the recommended settings following this Red Hat document:
How do you configure the fence device agent information option for the HP ILO 3?