Definition: OS virtualization

(1) The term may erroneously refer to traditional virtualization methods rather than the technique described below (see virtual machine).

(2) A method for splitting a server into multiple partitions called "containers" or "virtual environments" (VEs) in order to prevent applications from interfering with each other. A server running OS virtualization is also called a "virtual private server" (VPS).

The OS virtualization method differs from the traditional "virtual machine" (VM) method, because it shares one operating system just as in the typical user's computer. Decades ago, OS virtualization was built into various Unix operating systems, and it migrated into the Linux world in the mid-2000s. Microsoft also built in containers in Windows Server 2016. Docker is the most prominent software for setting up and managing containers (see Docker).

Advantages Over Virtual Machines (VMs)
In the traditional virtual machine method, each partition includes its own guest operating system, which communicates with the hardware through a virtual machine monitor (VMM). The more VMs running in the server at the same time, the more the entire system slows. However, containers communicate directly to the host operating system just as in a non-virtualized computer, and RAM and CPU cycles are minimized. Depending on the size of the app and required components in each container, hundreds of containers can exist in a single machine.

Most cloud computing providers only support virtual machines; however, containers can be deployed in this environment by running within a virtual machine. See virtual machine, Docker, Kubernetes, Virtuozzo and microservices.