Software For Virtualization At The Level Of Os Kernel. For example with Linux different distributions are fine but other operating systems such as Windows cannot be hosted. Containerization is a lightweight alternative to full installation of OS ie Virtual machines that involves only libraries and binary of the application which need to be run.
Because all of the containers share the services of a single operating system kernel they use fewer resources than virtual machines. Here the kernel of an OS allows more than one isolated user-space instances to exist. Docker is a set of platform as a service PaaS products that use OS-level virtualization to deliver software in packages called containers.
The software that hosts the containers is called Docker Engine.
Virtualization support on the Windows-based platform is still in the research stage. Common virtualization layers include the instruction set architecture ISA level hardware level operating system level library support level and application level see Figure 32. By far most reported OS-level virtualization systems are Linux-based. A slightly modified QEMU process is used as the display and execution containers for the virtual machines.