If you need to run multiple distros at the same time, test out new kernels, or just want to test new software in a ’sandbox,’ User Mode Linux is perfect for the job. Here’s how to get started.
User Mode Linux (UML) is a Linux kernel that runs as an application. To the host system — the underlying hardware and booted kernel — UML is just like ls, grep, Apache, Emacs, or vi: UML runs in user-space; it runs with user privileges; and multiple instances of UML can run simultaneously, where each instance gets its share of resources, such as memory and CPU time.
Of course, while UML looks like any other application to the host, it’s an unusually powerful one because each UML instance represents an entire, self-contained GNU/Linux system. Indeed, that’s often what UML is used for — to run one or more virtual Linuxes, or guest hosts, on top of a host system. (If you’re wondering if it’s possible to run a guest system on top of a guest system, running on a host system, the answer is yes, you can do that.) In fact, UML has rapidly become a popular way to test Linux kernels and distributions and a favorite way to run multiple, virtual Linux hosts on a single machine. Using UML, you can easily run multiple Linux distros on one x86-compatible machine at no additional cost except the time it takes to install and configure UML and create or install the guest hosts.
The UML project provides some pre-built guest host images — called filesystems in UML parlance — but you can also create your own with a modicum of difficulty, particularly if you have the right…
Please log in to view this content.
Not Yet a Member?
Register with LinuxMagazine.com and get free access to the entire archive, including:
