Monthly Archives: August 2011

Xen Logo and Mascot download page

Because of popular demand we have made available images and vector graphics of the Xen mascot, related images and templates. You can download images from the new logos page on under a creative commons license. The intention is that members in the Xen community can use the images for personal use, but also for commercial use as long as the images are used in relation to Xen and I also wanted to invite the creative members of our community to build and play with the imagery and let me know if you do. If you want to share, I will be happy to add your designs the mascot and image page on

Further website changes
Over the coming weeks, I will also roll out some website changes. Initially the changes will be mainly around the navigation of the website and I will be consolidating some of the content. The aim of the first set of changes is to make resources that are of relevance for Xen developers and Xen users more easily accessible. Later in the year, the site will be moved to new servers. This may involve some downtime: I will let you know 4 weeks in advance when what is affected.

Xen @ LinuxCon 2011

Konrad and I have been representing Xen at KVM Forum and LinuxCon 2011 last week. First of all I want to thanks Alexander Graf, Anthony Liguori and all the other members of the KVM community for the warm welcome and fruitful collaboration on many hot topics about virtualization. KVM and Xen have Linux and Qemu in common and share many problems that we can help each other solve. We had very interesting discussions regarding VFIO, USB redirection over the network, AHCI emulation, SPICE and many other subjects.

Then LinuxCon came along with many attendees and interesting presentations on the newest challenges in storage, network, ARM ports and so on. I particularly liked What to Expect From Linux Storage by James Bottomley and Optimizing Performance of Persistent Data Storage in KVM-based Clouds by Khoa Huynh. One thing that I noticed is that people really understand now that Xen is an integral part of the Linux ecosystem. Thanks to Linux 3.0 containing all the Xen pieces needed to run Dom0, everybody knows that we are first class citizens in the Linux world.

Somebody asked a question to Linus Torvalds about the supposed war the is going on between Xen and KVM, that lead to the famous quote “virtualization is evil“. The truth is that the is no war, I don’t know why people think that there is one. Xen and KVM might be competitors, but are different projects, with different architectures and constraints, both Open Source and both GPLv2, that have many goals and components in common. Competing and collaborating at the same time is in the very nature of Open Source and continuously happens at very different levels, between Gnome and KDE, among Linux distributions, among hardware vendors, and so on. There is really nothing strange or new going on.

The good news for the Xen project is that even though Linus dislikes virtualization technologies (they are evil after all :-)), he stated that he is pleased with the way Xen is run nowadays.
Technology discussions aside, Vancouver is a really beautiful city and the LinuxCon Gala “Roaring 20’s” was one of the best events I have ever attended. I recommend to checkout the pictures on the Linux Foundation website as soon as they are available 🙂

XenSummit Asia : Accepting Topics

The talk submission system for Xen Summit Asia, held Nov 2-3 in Seoul, Korea is now open for for anyone interested in speaking this year.

All speakers are required to submit their topic by Sept 16th, 2011 using the online tool or by e-mailing All submitted topics are reviewed by the Program Committee and a final agenda should be available by the end of September. If you have any questions about your topic or speaking at this event, please contact me for more information.

Program Management Committee

I am also still looking for volunteers to join the Program Management Committee for XenSummit Asia. As a PMC member you have the following responsibilities

  • Review submitted topics for the event (we will typically have 3 one hour calls and a bit of homework is needed)
  • Assist in compiling the final agenda for the event
  • If attending, introduce speakers – you don’t have to

Please get in touch with, if you want to join the PMC. We are aiming to have the first PMC meeting the week of Sept 12th.

4 weeks to Xen Hackathon Munich

Just a quick reminder that it is only 4 weeks to the Xen Hackathon in Munich, hosted by Fujitsu from Sept 13-15. There are still a few places free: if you plan to attend, do make sure to book your flights and hotels soon as the Oktoberfest begins on Sept 17 and hotels and flights will fill up quickly. If you do want to attend, drop Jürgen or me a line. There is no registration fee. However as an attendee you will need to cover your own travel, accommodation and other costs such as evening meals, etc. Information on location, hotels, etc. can be found on the Wiki.

Xen Hackathons give developers the opportunity to meet face to face to discuss development, coordinate, write code and collaborate with other developers as well as allowing everyone to put names to faces. The format is a mixture of unconference and time for coding, as needed at the time. The March Hackathon in Cambridge was a great success: our developer community released Xen 4.1 during the Hackathon and many of the items in the Xen 4.2 roadmap were discussed and planned. This time, I expect that key topics will be Xen 4.2, project Kronos and some discussion about the future of Xen.

I also wanted to thank Jürgen Groß from Fujitsu again, who is helping to make this event happen. See you in a few weeks!

XenSummit NA Material & XenSummit Asia Announcement

XenSummit NA Material
Just a quick note to say that I started posting the XenSummit presentations and videos on the XenSummit page. Almost all presentations are posted and can conveniently be downloaded via a zip file. The missing ones will follow later (in some cases approval is needed).

The recordings will follow later: the videos were saved in 1920p×1080p format and are stored on a server. It will take some time to download, process and upload them again. Apologies for that.

XenSummit Asia 2011 Announcement

I also wanted to remind you that XenSummit Asia was announced in Santa Clara. XenSummit Asia 2011 will be held in Seoul, Korea on Nov 2-3 and hosted and sponsored by Samsung and hosted by the University of Seoul.

If you would like to join the XenSummit Asia Program Management Committee, please send an e-mail to I will also be opening the call for presentations in the next two weeks.

Introducing Thomas Goirand, XCP packager

I’d like to introduce you to Thomas Goirand, who has volunteered to help us package the XenAPI toolstack for Debian as part of the Kronos project. Thomas is a Debian package maintainer and CEO of GPLHost. Thomas attended DebConf in Bosnia two weeks ago, where he did a great deal of work for the XCP-to-Debian packaging effort. We asked Thomas to write a short summary of his history with Xen, and his Project Kronos packaging efforts to date.

Hi my name is Thomas Goirand and I am CEO of GPLHost and Debian maintainer.
GPLHost has been providing a VPS hosting service based on Xen, since Xen 2.07 and we have been extremely happy with Xen. In particular on performance, stability and feature richness. When the idea of cloud computing started to take off, GPLHost was thinking about providing a cloud computing service. But we were in the same situation as in 2004/2005, when there was only UML as hypervisor and there was no open source technology that was fitting the bill. So when OpenStack started as a project, it was quite natural that we wanted to contribute and offer Openstack to our customers.

OpenStack development was one of the rare instances, where Debian was downstream of Ubuntu as OpenStack is developed on Ubuntu first, closely following the Ubuntu release cycle. One would think that Opestack code for Debian and Ubuntu is identical: Not true! About 2-3 dozens of patches were necessary to have OpenStack Nova, Glance and Swift ready for a Debian upload. Examples of differences are: Ubuntu uses upstart, when Debian uses insserv. As a consequence, init scripts had to be written nearly from scratch. Anyway, this work is done and OpenStack is available in Debian SID, as well as in our private repository for the Squeeze backport. By the way, I am searching for co-maintainers for these important packages.

In its current state, OpenStack can only be used with KVM as hypervisor, if you want to use Debian. You can of course use OpenStack with XCP, which is a CentOS appliance. But since I am a Debian developer and all GPLHost infrastructure is based on Debian, running an RPM based distribution is not an option. So I investigated if it is possible to package Xen-API (xapi) for Debian. The answers I got from both the OpenStack and xen-devel list were quite disappointing: XCP was, from the beginning, designed as an appliance, with many core packages being modified (kernel, lvm, and other libraries…). Porting it would be hard, because a lot of packages would have to be modified. This would make it quite difficult to port without the help of upstream XCP (yes, I’m talking about Citrix here).

Later, someone told me that my questions on public mailing lists sparked some internal discussion inside the XCP project which is led by Citrix. This led to the creation of project Kronos, whose goal it is to make Xen-API independent of CentOS and to also move away from an appliance only model. The first goal is to have a full Xen-API support for Ubuntu and that “apt-get install xen-api” would magically install everything. But the work would be done in Debian first and synched from SID to Ubuntu (which is part of the normal release cycle for Ubuntu). I was delighted. Of course, as Ian Campbell told me at Debconf 11, “it was ready to burst”, and I believe it would have probably happen anyway, even without me asking. Nevertheless, I am happy I asked at the time and am also happy to work on the packaging.

Anyway, the XCP project started porting their code from the CentOS XCP appliance. Since then, I started the packaging work, together with the help of “upstream” XCP (as in: Mike McClurg, Jonathan Ludlam, and others at Citrix in Cambridge).

Currently, the following packages are more or less ready:

  • libblktap
  • Xen 4.1.1 (modified current packaging to build the Xen OCaml libraries)

The following will still need to be built:

  • blktap DKMS package (since blktap wont ever make it to
  • xen-api-libs
  • xen-api

Even though I don’t really know much about OCaml, I know enough about Debian packaging to help out. And thanks to the help of Ian Jackson and Ian Campbell, who are both Debian Developers working on Xen and thanks to the OCaml task force at Debian who all agreed to review the packages, I believe it will be possible to create packages with good quality straight from the start. For those of you who never wrote packages (being RPM or .debs), you got to understand that writing quality packages is a tedious task and that it really improves quality to have more than a pair of eyes looking at the result.

Since DebConf 2011 we have the Linux 3.0 kernel available in Debian, including upstream support for Xen dom0 (others have already blogged about the inclusion of the dom0 features in for the 3.0 release). Thanks you to the Debian kernel team and in particular to Ben Hutching who did this one upload. With a little bit of extra effort, it will soon be possible to run XCP directly from Debian, with Xen 4.1.1 and Linux 3.0, all of which are available right now in SID. This means that this support should be available in Ubuntu as well: it looks we may be too late for Ubuntu 11.10, so we are working towards having XCP support in Ubuntu for the 12.04 LTS release (well, in my case, I’m working for Wheezy support, not for Ubuntu…).

All this is very exiting, and I am really looking forward to the work being done, for the first tests, with XCP first and then with OpenStack.