When you're dedicating a whole system to a single VM, you need have some spares for the underlying OS to keep it happy. The OS needs cores and RAM to be able t

When you're dedicating a whole system to a single VM, you need have some spares for the underlying OS to keep it happy. The OS needs cores and RAM to be able to keep the system up. Everything from network cards to services need some spare power, otherwise things go very wrong, and the experience of the tenant becomes very bad.