Hypervisors

OpenStack Nova supports multiple hypervisors. Some of them have more functions usable through OpenStack, while others have less.

Kernel-based Virtual Machine

Kernel-based Virtual Machine (KVM) is a hypervisor that is currently part of the Linux Kernel since Linux 2.6.20 released in February 2007. Initially, it was available only for x86 platforms, but today a large number of platforms are supported, including ARM, IA-64, PowerPC, and S/390.

By default, KVM works in a fully virtualized environment, while with some guests, it is possible to use paravirtualization for improved performance.

Being part of the core Linux Kernel is one of the biggest advantages of KVM, since it's often updated and very widely used. Other advantages are its low Total Cost of Operation (TCO), which is calculated to be between 30 percent to 90 percent cheaper than the other leading platforms (open source and proprietary), due to its high efficiency and no license cost.

This comes at the cost of not always...