One of my favorite sayings is, “Open source software is as much about people as it is about technology.” This week in Santa Clara, CA over one hundred people active in the open source Xen hypervisor community – largely developers and power users – gathered to discuss the state of the popular open source hypervisor.
During the event kickoff, Citrix CEO Mark Templeton noted that the etymology of Xen can be traced to the Greek word xenos, which means a traveler or guest brought into a relationship – a good metaphor for this particular technology and its open source community. During his welcome address Templeton cited some stats around the Xen hypervisor:
- Provides the underpinnings of more than 6 million Xen Desktops
- 12 percent of all new virtualized servers in 2011 will use Xen
- Xen is the leading hypervisor for public cloud computing, providing the foundation for cloud hosters Amazon, Rackspace, Linode and GoGrid (via JackofAllClouds.com study January 2011)
Though the Xen.org site hardly mentions Citrix (which owns the Xen marks and copyright), it maintains a stealthy presence in the project. Templeton notes this to be by design. He highlights that Citrix doesn’t want to own the project, but rather be a great steward of the project, citing the goals of better governance and interactivity with the Xen community. This model isn’t unique, having proven successful for open source maven Red Hat with its Fedora project.
Looking to the future of Xen, Ian Pratt, the Chairman of Xen.org and the SVP of Products at Bromium, a stealth start-up purported to be working on virtualization security in the cloud, also delivered a compelling message. Pratt shared a vision of the Xen that was first conceived in research conducted at Cambridge University back in 2003. He pointed out some of the under-utilized features of the Xen architecture, including the Xen memory introspection API which enables a virtual machine to interpose itself onto another virtual machine and potentially debug other VMs, or even run a malware scanner on top of another VM. Pratt also noted that the number one priority for Xen is secure isolation between VMs as a key consideration for cloud computing. Pratt noted that the intention of Xen was not to have the entire hypervisor run in a privileged domain., but for Xen to isolate driver domains to enhance security and improve availability.
Pratt, believes that the Xen Cloud Platform could be the future of Xen, enabling developers to take full advantage of the Xen architecture. He also notes that having hypervisors on client devices will provide architectural security, reliability and performance benefits. Though the XCP acronym stands for “Xen Cloud Platform,” theXCP project lead, Mike McClurg, added that he likes to think of it as standing for “Xen Community Platform.”
During the main keynote, Pradeep Vincent of Amazon Web Services, the ultimate Xen power user, shared the benefit of his experience with Xen with anecdotes from Amazon Elastic Compute (EC2), which uses Xen to run the world’s largest cloud computing environment. He shared his insights on scaling virtualization for Amazon’s cloud, noting the biggest challenges in the cloud are around multitenancy for performance and I/O scaling. He also mentioned fine-grained resource allocation to be of great importance.
Xen is an interesting project, with companies such as Amazon, Citrix and Rackspace building products around the virtualization technology. Not to mention numerous hosting companies and users who depend on Xen. This is only possible because Xen is open source and actively supported and developed by many passionate people with a vested interest in the software.