Rackspace has built its Windows-based cloud service on top of Citrix’s XenServer hypervisor, rather than the more basic open source version of Xen, and plans to move its whole cloud infrastructure over to XenServer.
The move is a strong endorsement for Citrix, which is not only battling VMware in the cloud computing market but also faces facing a strong challenge from Linux-based KVM in the world of open source virtualization.
Rackspace’s cloud services, which offer on-demand access to virtual server and storage capacity, have typically run on the core version of Xen. But Rackspace apparently turned some heads last week at Citrix’s Synergy conference when the company said it will move its cloud over to Citrix XenServer.
So far, XenServer is just being used in Rackspace’s Cloud Servers for Windows Beta, a fact which has been public knowledge for several months. But XenServer will gain a much more prominent role in Rackspace’s cloud, Lew Moorman, Rackspace’s cloud chief, told me in an interview.
“We do plan to move the entire [cloud] infrastructure over to XenServer,” Moorman said.
The more robust XenServer is needed to build a cloud service that can host production applications for an enterprise customer, Moorman said. It’s easier to develop on top of Citrix’s XenServer than the core Xen hypervisor, and XenServer has been validated by Microsoft, so Rackspace will receive full Windows support, he said.
“We are focused on the business user in a company that is going to run production-ready applications,” Moorman said. “We needed to have a fully supported Windows instance.”
Early use cases for cloud computing were heavily focused on coding, number crunching and various types of Linux-based functions, Moorman said. But now the cloud is becoming mature enough for production applications, and that typically means running on Windows, Moorman said. The Cloud Servers for Windows platform should come out of beta later this quarter, he said.
Citrix has made XenServer free and is moving the software over to the open source domain, just as the core Xen hypervisor always has been.
Rackspace, which has existing partnerships with both Citrix and Microsoft, therefore won’t have to pay anything extra to use and support XenServer, according to Moorman.
Just because Rackspace makes heavy use of XenServer doesn’t mean it’s ignoring other hypervisors. Rackspace’s so-called private cloud service is based on VMware, and provides customers with dedicated hardware and more features, albeit at a higher cost.
“For the public cloud, Citrix was the best fit,” Moorman said. “VMware is really built with traditional enterprise models in mind. They have different strengths and weaknesses in their technology.”