A virtual machine is a cloud-based or on-premises based virtual computer which runs under the control of a hypervisor host cluster. A hypervisor is computer software, firmware or hardware which is able to create and run virtual machines. There are two basic types of server virtualization, i.e. type 1 and type 2. Type 1 hypervisors provide install their own operating system (e.g. VMWare ESXi) and boot directly to that operating system. Type 2 hypervisors install themselves as server role on top of another operating system (e.g. HyperV server role). There are two different types of virtualization, namely Full virtualization and Paravirtualization.