UPDATE: HP contacted us on Oct. 24 to let us know that "Ubuntu will not be the primary operating system, but it would be more accurate to say that they are the first one in our current private beta." Canonical has updated its own announcement to reflect this more accurate phrasing, with the Canonical blog now saying Ubuntu is "one of the initial lead host and guest operating [systems] powering [HP's] Public Cloud."

Original article: Ubuntu Linux will be the primary operating system powering HP’s upcoming cloud service, Ubuntu maker Canonical said last week. HP recently opened a private beta program for an infrastructure-as-a-service cloud that will offer both compute and storage capacity, using the OpenStack open source cloud platform.

OpenStack, which was recently spun off from Rackspace, is designed to work with multiple operating systems and virtualization platforms. Options include VMware, Hyper-V, Windows and Xen. HP is going with an all-open source lineup, with the Linux-based KVM as its hypervisor, and Ubuntu for the operating system.

“HP has chosen Ubuntu as the lead host and guest operating system powering their Public Cloud,” Canonical said in a blog post. “HP and Canonical are working closely together during the current private beta to make certain that we provide the most secure, scalable, business-class cloud to companies of all sizes.”

While Ubuntu serves as the “reference OS” for OpenStack, HP isn’t required to use it. “This is an important announcement on several fronts—that OpenStack is seen as the platform of choice for building out the largest Public Clouds, and that Ubuntu has what it takes to power OpenStack clouds as a scalable and hardened host OS and responsive and flexible guest OS,” Canonical said.

Although Ubuntu is getting favorable treatment, HP could still allow customers to host multiple operating systems, just as its competitors do. Rackspace Cloud Servers and Amazon EC2, which both use Xen virtualization, allow hosting of various operating systems including Windows and various flavors of Linux.

The HP cloud is targeted at developers, ISVs and business customers, with the ability to deploy virtual machines and object storage capacity on demand. HP has reached its initial limit for customers during the private beta, but people can still sign up to get access when the beta is expanded.