The Week in Review: Red Hat vs. Sun

Dr. Oliver Diedrich

Adding virtualisation for a complete open source stack

Red Hat is continuing to expand its open source stack with Qumranet and the KVM virtualisation technology. Sun still has its nose in front, already offering VirtualBox as a fully supported product.

In acquiring Qumranet, Red Hat has made a significant addition to its open source stack in the form of the open source virtualisation solution Kernel Virtual Machine (KVM) and KVM-based desktop virtualisation system SolidICE. Red Hat has already announced that it will only continue to support Xen for some years, thereby – at least from the point of view of the major Linux distributors – more or less bringing down the curtain on the current Linux standard for virtualisation.

The switch from Xen, which is well-established in the Linux world, to newcomer KVM does not come as a complete surprise. Fedora, the community version of Red Hat's Linux distribution, has supported KVM since Fedora 7. Red Hat's virtualisation management tools havebeen able to work with both KVM and Xen for some time, and the open source specialist had already announced a KVM-based embedded hypervisor at this year's Red Hat Summit.

The switch to KVM makes a lot of sense. Xen is still not fully integrated into the Linux kernel, and Xen is only available as patches for Linux kernel 2.6.18, now two years old. Users wanting to build an up to date Linux system with Xen support have to port the patches to a more recent kernel themselves. In contrast, KVM has been part of the kernel since Linux 2.6.20 – which saves the distributors a lot of work.

Strategic considerations are likely to have weighed more heavily in the decision to purchase Qumranet. XenSource, the company behind Xen, was taken over by Citrix a little over a year ago. Since then, the open source project has been coordinated by a committee made of a number of companies, including Red Hat, which collaborate on Xen. Despite this, Citrix, which with the XenSource developer team remains the largest supplier of code, is still largely able to set the direction for development and Citrix's interests may not always overlap fully with Red Hat's. Having its own virtualisation technology offers Red Hat independence in an area expected to become increasingly important over the next few years.

Red Hat is in good company in having its own virtualisation solution. Sun, which has steered heavily towards an open source future under Jonathan Schwartz, took over VirtualBox early this year. The release of version 2 on the same day as Red Hat's Qumranet/KVM announcement offers enterprise customers comprehensive support for the virtualisation solution on both desktop and server.

When Innotek, the company which developed VirtualBox was taken over, the official line was that VirtualBox was seen primarily as a desktop solution for developers who wanted to run multiple operating systems and as a complement to the Xen based xVM server solutions. We speculated at the time that Sun may have been keen to reduce dependence on Xen. Sun is now describing xVM VirtualBox as a fully supported solution for deployment on desktops and servers.

The simultaneous announcements – the takeover of Qumranet and enterprise support for VirtualBox – show just similarly Sun and Red Hat are positioning themselves. Both companies want to be able to deliver a complete open source stack for enterprises as full service providers. The open source software offered by the two companies, from virtualisation, to operating systems, cluster extensions and distributed file systems (Red Hat's Global File System, Sun's Solaris Cluster and Lustre), to middleware (Red Hat's JBoss, Sun's Glassfish) is very similar. Sun of course has a far larger portfolio, even in the open source field – think of Java or MySQL for example – but many of its products are still closed source.

One way of looking at it is that Red Hat and Sun are converging on the same goal but from different directions, one as an open source company moving to become a systems supplier, the other as a system supplier moving towards open source. Customers may eventually have a choice between two complete open source stacks.

(odi)