KVM automatically overprovisions memory. Probably other hypervisors do it too. The utilization numbers only show that a particular administrator doesn't know

KVM automatically overprovisions memory. Probably other hypervisors do it too. The utilization numbers only show that a particular administrator doesn't know how to use technology X, but knows better how to use technology Y or that the defaults in technology Y happen to work better for a particular benchmark (and the administrator doesn't know how to use either X or Y). I believe that the later is usually the case. Compounded by laziness and lack of real financial incentive to optimize every last bit of the existing infrastructure. The situation will, however, flip on its head if you want to build a reliable high-performance system. In this case Kubernetes will be an impendiment. Nothing it does it does well or can be optimized / configured to do well. When push comes to shove, you'll have to either get rid of Kubernetes, or lose the race.