Open Source Journal

There has been a significant amount of derision heaped on Xen after its successful integration into the Linux kernel last month.

One wouldn't think such criticism is warranted, since the inclusion of Xen in the Linux kernel puts it on equal footing with KVM.

Yet, when Oracle's Wim Coekaerts announced the inclusion of Xen code for DomO and DomU support in Linux, many industry observers took the opportunity to lambaste Xen for being too-little-too-late.

True, KVM has been more successful in the briefer time it has existed. Xen has had plenty of opportunity to be the go-to virtualization platform for Linux. KVM, however, exploded in popularity and was fully integrated into the Linux kernel by the time Linux 2.6.20 was released. It's now the virtualization platform of choice for Red Hat Enterprise Linux, Canonical's Ubuntu Server, and SUSE Enterprise Server Linux (though SLES also supports Xen as well).

The fact that Xen is now in the Linux kernel is a cause for celebration. Customers who want to work with a virtualization solution now have a choice of not one but two solid virtualization tools for Linux. This proves once and for all that Linux is not only a viable cloud virtualization platform; it's in reality the most desirable platform for use in the cloud.

Xen and KVM each have their own respective strengths. Despite their differences - indeed, because of their differences - their mutual presence within the Linux kernel validates that cloud computing will truly be commoditized, no matter which approach to virtualization is desired by customers.

That's a big perspective, much bigger than the narrow view of Xen being "late."

To have real commoditization, the choice of the underlying platform must be driven by the application, not the platform features. No matter which virtualization toolset customers prefer (KVM or Xen), Linux has now become the crucible of both. Applications become the important deciding factor.

The presence of both in the Linux kernel should put VMware on notice that their market position with VMware ESX Server is becoming tenuous at best, since commoditization has finally been achieved.

The industry is certainly coming around to that conclusion. KVM, for instance, enjoys broad industry support by Red Hat and other members of the Open Virtualization Alliance (OVA). OVA's members, including the 65 new members of which Convirture is one, understand that having KVM in the Linux kernel means proprietary approaches like VMware's are no longer important.

The two virtualization systems can be used equally by independent cloud vendors to break the hold VMware and Citrix have on the cloud market. OVA and its expanded membership have all but declared open war on VMware in particular and sees itself as a chance to end VMware domination. With Xen's inclusion in the Linux kernel, industry alignment around Xen can be expected as well.

The choice demonstrates once and for all that Linux is the real and right platform for virtualization. And since virtualization is the first step toward cloud computing, Linux ultimately becomes the best choice for the cloud.