We can define Virtualization as the creation of the virtual rather than actual version of Operating System, a server, or a network resource. Operating System Virtualization is the use of the software to allow a piece of hardware to run multiple OS images at the same time.
The key use of the virtualization technology is the Server Virtualization, in which Hypervisor, a software layer is used to emulate the underlying hardware. The concept of virtualization is needed because most guest operating systems and applications don’t need the full use of the underlying hardware.