User-mode Linux (UML) #
What is it? #
A virtualization system for Linux based on architectural port of the Linux kernel to its own system call interface, which enables multiple virtual Linux kernel-based OSes (guests) to run as an application within a normal Linux system (host). It is already part of the main kernel.
Linux has also been ported to a number of architectures without a PMMU, although functionality is then obviously somewhat limited. Linux has also been ported to itself. You can now run the kernel as a userspace application - this is called UserMode Linux (UML). [1]
Why is it used? #
- Enables you to boot a full Linux kernel inside of a user space. Think of it as VMWare but only for Linux.
Where is it used? #
- Widely used for development and much easier to debug – mostly kernel development
- Hosting virtual servers
- For setting up educational systems
- As a sandbox