Virtualization

Virtualization is a technology that lets many isolated, independent environments run on a single physical machine. Instead of dedicating a whole server to one task, it splits its resources — processor, memory and disk — among several virtual machines, each behaving like a separate, self-contained computer with its own operating system.

How virtualization works

At the heart of virtualization is the hypervisor — a software layer that manages the division of hardware and the isolation of environments. The hypervisor allocates each virtual machine a guaranteed portion of resources and ensures that a failure or heavy load on one instance does not affect the others. Thanks to this isolation, many independent services belonging to different customers can safely run on one powerful server.

Uses

Virtualization is the foundation of modern hosting and the cloud. It is what makes the VPS service possible — a virtual server with dedicated resources running alongside others on the same machine. It also enables better use of hardware, fast creation and cloning of environments, and flexible scaling: as traffic grows, further instances can be launched and the load spread among them behind a load balancer. A related, lighter technique is containerization, for example Docker, which divides one operating system into isolated containers rather than creating full virtual machines. The two approaches often coexist — virtual machines provide hard isolation, and containers provide fast, economical application startup. For a service owner, virtualization mainly translates into flexibility and cost efficiency, since it lets you pay for dedicated resources instead of maintaining an underused physical server.