A KVM system is not a BMC. Running a cluster (even a fairly small one) you probably want power control, e.g. with powerman, serial console availability, e.g. with conman, metrics, e.g. via freeipmi and some monitoring solution, and probably logs for alerts. Control and monitoring need to be out of band.

(Powerman, conman, and freeipmi come from Livermore for use with serious HPC systems.)