Xen is an open source Virtual Machine Monitor (VMM) originally developed by the Systems Research Group of the University of Cambridge Computer Laboratory, as part of the UK-EPSRC funded XenoServers project.
Xen can securely execute multiple virtual machines, each running its own operating system, on a single physical system with close-to-native performance.
The Xen Cloud Platform addresses the needs of cloud providers, hosting services and data centers by combining the isolation and multitenancy capabilities of the Xen hypervisor with enhanced security, storage, and network virtualization technologies.
Features include:
- Small footprint and interface. Xen uses a microkernel design, with a small memory footprint and limited interface to the guest.
- Operating system agnostic.
- Driver Isolation: Xen has the capability to allow the main device driver for a system to run inside of a virtual machine. If the driver crashes, or is compromised, the VM containing the driver can be rebooted and the driver restarted without affecting the rest of the system.
- Paravirtualization: Fully paravirtualized guests have been optimized to run as a virtual machine. This allows the guests to run much faster than with hardware extensions (HVM). Additionally, Xen can run on hardware that does not support virtualization extensions.
- Advanced Memory Management:
- Memory Ballooning.
-
- Memory Sharing.
-
- Memory Paging.
-
- TMEM.
- Resource Management:
- Cpupool.
-
- Credit 2 Scheduler (experimental).
-
- NUMA scheduler affinity.
- Scalability:
- 1GB/2MB super page support.
-
- Deliver events to PVHVM guests using Xen event channels.
- Interoperability / Hardware support:
- Nested Virtualisation (experimental).
-
- HVM PXE Stack.
-
- Physical CPU Hotplug.
-
- Physical Memory Hotplug.
-
- Support for PV kernels in bzImage format.
-
- PCI Passthrough.
-
- X86 Advanced Vector eXtension (AVX).
- High Availability and Fault Tolerance:
- Live Migration, Save & Restore.
-
- Remus Fault Tolerance.
-
- vMCE.
- Network and Storage:
- Blktap2.
-
- Online resize of virtual disks.
- Security:
- Driver Domains.
- Device Model Stub Domains.
- Memaccess API.
- XSM & FLASK.
- XSM & FLASK support for IS_PRIV.
- vTPM Support.
- Tooling
- gdbsx.
- vPMU.
- Serial console.
- xentrace.
- Device Models and Virtual Firmware for HVM guests:
-
- Traditional Device Model.
- Qemu Upstream Device Model.
- ROMBIOS.
- SeaBIOS.
- OVMF/Tianocore (experimental).
-
- PV Bootloader support:
- PyGrub support for GRUB 2.
- PyGrub support for /boot on ext4.
- pvnetboot support.
- NUMA scheduling affinity.
- Openvswitch integration.
Website: www.xenproject.org
Support: FAQ
Developer: Linux Foundation Collaborative Project
License: GNU GPL v2
Xen is written in C. Learn C with our recommended free books and free tutorials.
| Popular series | |
|---|---|
 | The largest compilation of the best free and open source software in the universe. Each article is supplied with a legendary ratings chart helping you to make informed decisions. |
 | Hundreds of in-depth reviews offering our unbiased and expert opinion on software. We offer helpful and impartial information. |
 | The Big List of Active Linux Distros is a large compilation of actively developed Linux distributions. |
 | Replace proprietary software with open source alternatives: Google, Microsoft, Apple, Adobe, IBM, Autodesk, Oracle, Atlassian, Corel, Cisco, Intuit, and SAS. |
 | Awesome Free Linux Games Tools showcases a series of tools that making gaming on Linux a more pleasurable experience. This is a new series. |
 | Machine Learning explores practical applications of machine learning and deep learning from a Linux perspective. We've written reviews of more than 40 self-hosted apps. All are free and open source. |
 | New to Linux? Read our Linux for Starters series. We start right at the basics and teach you everything you need to know to get started with Linux. |
 | Alternatives to popular CLI tools showcases essential tools that are modern replacements for core Linux utilities. |
 | Essential Linux system tools focuses on small, indispensable utilities, useful for system administrators as well as regular users. |
 | Linux utilities to maximise your productivity. Small, indispensable tools, useful for anyone running a Linux machine. |
 | Surveys popular streaming services from a Linux perspective: Amazon Music Unlimited, Myuzi, Spotify, Deezer, Tidal. |
 | Saving Money with Linux looks at how you can reduce your energy bills running Linux. |
 | Home computers became commonplace in the 1980s. Emulate home computers including the Commodore 64, Amiga, Atari ST, ZX81, Amstrad CPC, and ZX Spectrum. |
 | Now and Then examines how promising open source software fared over the years. It can be a bumpy ride. |
 | Linux at Home looks at a range of home activities where Linux can play its part, making the most of our time at home, keeping active and engaged. |
 | Linux Candy reveals the lighter side of Linux. Have some fun and escape from the daily drudgery. |
 | Getting Started with Docker helps you master Docker, a set of platform as a service products that delivers software in packages called containers. |
 | Best Free Android Apps. We showcase free Android apps that are definitely worth downloading. There's a strict eligibility criteria for inclusion in this series. |
 | These best free books accelerate your learning of every programming language. Learn a new language today! |
 | These free tutorials offer the perfect tonic to our free programming books series. |
 | Linux Around The World showcases usergroups that are relevant to Linux enthusiasts. Great ways to meet up with fellow enthusiasts. |
 | Stars and Stripes is an occasional series looking at the impact of Linux in the USA. |