If you wish to install something like OpenStack on Red Hat and deploy it with Director service, you will be asked for some kind of IPMI (Inteligent Platform Management Tool) so that your can control servers (bare metal) from one point, reboot and control power status of the machines you deploy to… HPE has iLO, Dell has iDRAC…

That is all well if you are deploying to bare metal, but what if you wish to control virtual machines in the same manner. You will need VirtualBMC.