Virtualization refers to running multiple virtual computers, or virtual machines, inside a single physical computer. While the basic idea of virtualization is old (dating back to mainframe computers in 1960s), it has become mainstream only in the last 10-15 years. Today, most new servers are virtualized.
- Hypervisor is the operating system running on actual hardware. Virtual machines run as processes within this operating system. Sometimes the hypervisor is called
- Virtual machine is a virtual computer running under a hypervisor.
- Container is a lightweight virtual machine that runs under the same operating system instance (kernel) as the hypervisor. Essentially, a container is nothing but a group of processes with their own name space for process identifiers etc.
- Virtual network is a logical network within a server, or possibly extending to multiple servers or even multiple data centers.
- Virtualization software is software that implements virtualization on a computer. It can be part of an operating system (or a special version of an operating system) or an application software package.
Virtualization is the basis of modern cloud computing.
Virtualization drivers in recent years have included:
- More powerful hardware, allowing each machine to run multiple applications simultaneously
- Pressure to lower IT costs and simplify IT administration
- Need to manage large-scale installations and clusters, such as server farms
- Improved security, reliability, scalability, and device independence
- Ability to mix multiple operating systems on same hardware.