Monthly Archives: January 2011

Welcome from your new Community Manager

by Lars Kurth

A week ago, I started as Community Manager for I spent last week getting up-to-speed on the basics and feel that now it is time for a quick introduction.

I have worked as part of and with various open source communities for 9 years now. I won’t bore you with the details: if you want to find out more, check out my Wiki profile. I am very excited to work with you all and be part of the Xen community, which has been leading the open source cloud computing revolution for a while. I am convinced that it will stay exciting and grow and I hope I can make a big contribution.

For me personally, moving from mobile and semiconductors into virtualisation and cloud computing, will create a bit of a learning curve. So please bear with me when I cannot help immediately in all matters. Please feel free to contact me at any time with any question or ideas, or for all things Xen. I will follow up and make things happen. My e-mail address is and I am usually on skype on lars.kurth during UK office hours.

At this point, I wanted to share what I will be working on over the coming weeks:

  • Work out the event plan for 2011: of particular importance is the next Xen Asia and the Xen Global Summit in the USA.
  • Rejuvenate the web-site, both in terms of content as well as infrastructure. This is a project that Stephen has started and which I feel is really important. You will see a number of smaller changes over the coming weeks and bigger changes after that.
  • The community is very vibrant, but operates to a set of unwritten rules that have evolved over time. I will need to learn these rules anyway: thus, I will work with you and write down how governance works.
  • Communication, communication, communication!

I strongly believe in openness, collaboration and listening and will thus put mechanisms in place which allow you to let me know what worked well in the past and also what did not work so well. This will create an opportunity to make changes for the better. And: I will always make my plans and ideas available for review and commenting, such that you have a voice.

I am excited to work with you all and hopefully meet many of you in the near future.

Best Regards


Linux 2.6.37: first upstream Linux kernel to work as Dom0

by Stefano Stabellini

Linux 2.6.37, released just few days ago, is the first upstream Linux kernel that can boot on Xen as Dom0: Linus pulled my “xen initial domain” patch series on the 28th of October and on the 5th of January the first Linux kernel was released with early Dom0 support!

Dom0 is the first domain started by the Xen hypervisor on boot and until now adding domain 0 support to the Linux kernel has required out of tree patches (note that NetBSD and Solaris have had Dom0 support for a very long time). This means that every Linux distro supporting Xen as virtualization platform has to maintain an additional kernel patch series.

Distro maintainers, worry no more: Dom0 support is upstream! It is now very easy to enable and support Xen in the standard kernel distro images and I hope this will lead to an upsurge in distribution support for Xen. Just enabling CONFIG_XEN in the kernel config of a 2.6.37 Linux kernel allows the very same Linux kernel image to boot on native, on Xen as Dom0, on Xen as normal PV guest and on Xen as PV on HVM guest!

That said, the kernel backends, in particular netback and blkback, are not yet available in the upstream kernel. Therefore a 2.6.37 vanilla kernel can only be used to start VMs on the very latest xen-unstable. In fact xen-unstable contains additional functionalities that allow qemu-xen to offer a userspace fallback for the missing backends. This support will become part of the Xen 4.1 release which is due in the next couple of months.

In the short term the out of tree patch set has been massively reduced. It is expected that the xen.git kernel tree will soon contain the proposed upstreamable versions of the backend drivers. I strongly encourage everyone to pull these and start testing upstream dom0 support!

I want to thank Jeremy Fitzharding, Konrad Rzeszutek Wilk, Ian Campbell and everyone else who was involved for the major contributions and general help that made this possible.