Virtualization refers to technology that simulates hardware, such as CPU/memory on top of actual hardware, hence creating multiple virtual machines on top of actual hardware. The underlying hypervisor layer traps instructions that are privileged and/or go to shared state and simulate isolated environments for each virtual machine.

Virtualization enables multiple benefits, including the following:

• Better hardware resource utilization
• Allowing you to save/restore the state of a machine
• Easier maintenance, including features such as the migration of virtual machines from one physical host to another, allowing for easier maintenance of physical hardware
• Allowing applications that run on different operating systems to be deployed on standard hardware

There are many virtualization vendors including the following:

• Microsoft Hyper-V
• Linux Kernel Virtual Machine (KVM), Qemu, and related ecosystems such as Openstack
• Citrix Xenserver