What are some good Xen al­tern­at­ives? 5 options

Depending on use case and per­form­ance re­quire­ments, it might make sense to consider looking for a Xen al­tern­at­ive. We’ve compiled a list of five al­tern­at­ives to Xen and included the ad­vant­ages and dis­ad­vant­ages of each hy­per­visor.

The best Xen al­tern­at­ives in direct com­par­is­on

KVM

KVM (Kernel-based Virtual Machine) is vir­tu­al­isa­tion software based on Linux and has been in­cor­por­ated into the Linux kernel from version 2.6.20 onward. Developed by Red Hat, it can function as a type 1 hy­per­visor through a setup that is similar to Xen. Typically, it operates as a type 2 hy­per­visor though, which is why it’s commonly regarded as a hybrid hy­per­visor solution.

With KVM, you can host various guest systems, such as BSD (Berkeley Software Dis­tri­bu­tion), Solaris, Windows, ReactOS and macOS, making it a versatile al­tern­at­ive to Xen.

In­teg­ra­tion into the Linux kernel ensures that KVM con­sist­ently receives updates for security and per­form­ance. The hy­per­visor offers robust security features, including combining SELinux and sVirt (secure vir­tu­al­isa­tion) to protect and isolate your virtual machines.

By deploying KVM on a supported Linux dis­tri­bu­tion such as RHEL, you can enhance its func­tion­al­ity. For example, you can boost system per­form­ance or fa­cil­it­ate resource sharing among guest systems.

Vir­tu­al­Box

Ori­gin­ally developed by InnoTek Sys­tem­ber­a­tung GmbH in Baden-Württem­berg, Germany, the Xen al­tern­at­ive Vir­tu­al­Box has been main­tained by the U.S. company Oracle since 2008. Unlike Xen, Vir­tu­al­Box is a type 2 hy­per­visor that runs on Windows, Linux, macOS and Solaris platforms. In terms of guest systems, the ap­plic­a­tion has hardly any re­stric­tions. In addition to Windows and Linux systems, various Solaris and BSD editions can also be used as hosts. Vir­tu­al­Box offers lots of flex­ib­il­ity when it comes to operating systems and gives you the option of desktop vir­tu­al­isa­tion, which is not possible with Xen.

Vir­tu­al­Box does not, however, allow you to transfer VMs between physical hosts during live op­er­a­tions without ex­per­i­en­cing downtime, resulting in less flex­ib­il­ity for virtual machine migration. Since users need to carry out mi­gra­tions manually, the vir­tu­al­isa­tion ap­plic­a­tion is less suitable for projects that require very high avail­ab­il­ity.

A clear advantage of the Oracle software is its ease of use for beginners. The graphical user interface makes managing virtual machines easy, even for beginners who may have little ex­per­i­ence with command-line inputs like those required in Xen.

Xvisor

Like Xen, Xvisor (short for Xtensible Versatile hy­per­vISOR) is also an open-source type 1 hy­per­visor that is known for its high flex­ib­il­ity and port­ab­il­ity. Xvisor demon­strates its im­press­ive ver­sat­il­ity with the large number of ar­chi­tec­tures it supports. In addition to x86 and x86_64, supported CPU ar­chi­tec­tures include ARM and RISC-V.

The Xvisor source code can be ported to any 32- and 64-bit platforms as long as a Paged Memory Man­age­ment Unit (PMMU) and a port of the GNU C compiler (GCC) are available. Although the Xen al­tern­at­ive primarily relies on full vir­tu­al­isa­tion, allowing numerous un­mod­i­fied guest OSs, it binds the host system to a Linux dis­tri­bu­tion.

Xvisor vir­tu­al­isa­tion is efficient and saves space, partly because the software does not in­cor­por­ate any security en­hance­ments. Similar to Xen, you can enable para­vir­tu­al­isa­tion if the ar­chi­tec­ture you are using supports it.

QEMU

QEMU, short for Quick EMUlator, is a Xen al­tern­at­ive that can be used as an emulator or a type 2 hy­per­visor. As a hy­per­visor, QEMU achieves close to native per­form­ance by executing guest code directly on the host CPU. However, for this purpose, the vir­tu­al­isa­tion software has to use either the Xen hy­per­visor or the Linux KVM kernel module.

Compared to Xen, QEMU offers a much larger ecosystem and supports sig­ni­fic­antly more ar­chi­tec­tures and operating systems. For this reason, the program is suitable for a wide range of ap­plic­a­tions including de­vel­op­ment, testing and operation of legacy software.

As a type 2 hy­per­visor, QEMU does not have direct access to hardware resources, resulting in slightly lower per­form­ance compared to Xen. In return, however, the tool is more user-friendly thanks to its graphical user interface. In addition to a large and active community that provides regular updates, the vir­tu­al­isa­tion solution has also been in­teg­rated into many other vir­tu­al­isa­tion solutions and cloud platforms.

UTM

UTM is a vir­tu­al­isa­tion solution that can be used to emulate various operating systems on your Mac device, iPhone or iPad (iOS 11 or higher). Among other things, the software uses Apple’s hy­per­visor vir­tu­al­isa­tion framework to run ARM64 operating systems on devices with Apple Silicon pro­cessors, achieving almost native per­form­ance.

On older Macs with Intel pro­cessors, you can vir­tu­al­ise guest systems with x86 and x86_64 ar­chi­tec­ture if necessary. The hy­per­visor also supports various other ar­chi­tec­tures such as ARM32, MIPS, PPC and RISC-V.

This Xen al­tern­at­ive is an excellent choice if you want to run Windows systems on your Mac or iOS mobile device.

UTM is built on the solution we looked at in the last section, QEMU. While QEMU is very flexible and powerful, like Xen, it may pose some chal­lenges for beginners. Due to the abundance of command-line options and flags in these two options, they are difficult to set up and configure when compared with UTM.

UTM was developed with the aim of offering users the flex­ib­il­ity of QEMU and at the same time, being as user-friendly as possible.