Ubuntu has been named "lead host and guest operating system" on Hewlett-Packard's fledgling OpenStack-based cloud.

Canonical has been working closely with HP during the tech juggernaut's cloud beta, which opened one month ago, to ensure Ubuntu provides a secure and scalable "business-class" cloud "for companies of all sizes".

Ubuntu-steward Canonical posted the news online here, which will be delivered in person by Canonical's chief executive Jane Silber at the OpenStack conference in Boston, Massachusetts later on Friday.

Canonical said the development is important announcement for several reasons. "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.

Making Ubuntu the number one guest operating system on HP's cloud is a big bet by the maybe will, maybe won't PC maker. The company's cloud is not yet available, but HP's already promised it'll suit all companies of all sizes and also all clouds public and private.

Canonical decided earlier this year to put OpenStack at the heart of the server version of its Linux distro and retreat from Eucalyptus. This had been the preferred means of spinning up your own clouds using Amazon Machine Images (AMI).

The company said future versions of the Ubuntu Cloud would use OpenStack as a foundation technology. Eucalyptus is now simply an option people can use along with Ubuntu.

Canonical joined the OpenStack project in February. Ubuntu founder Mark Shuttleworth in March said there was a need to prioritise three months after he'd said Ubuntu would have both OpenStack and Eucalyptus-based cloud options - he seemed to be referring to Ubuntu 11.04 in April. The forthcoming Ubuntu Enterprise Cloud (UEC) package of Ubuntu Server 11.10 will include the OpenStack stack.

Ubuntu had been an early supporter of Eucalyptus: Ubuntu 9.10 lets you spin up your own Amazon-compatible clouds based on AMIs using the Eucalyptus project's code. Shuttleworth, meanwhile, had been an investor in the start-up selling Eucalyptus-based services, Eucalyptus Systems. ®