Monthly Archives: July 2012

Xen 4.2 Release Plan Update: Xen 4.2.0-rc1 released

Last week we finally crossed the last major remaining issues off the Xen 4.2 TODO list. This means that the release plan now looks like this:

  • 19 March — TODO list locked down
  • 2 April — Feature Freeze
  • 30 July — First release candidate WE ARE HERE
  • Weekly — RCN+1 until release

That’s right, we’ve now released Xen 4.2.0-rc1!

There’s still a couple of smaller outstanding items which we hope to resolve shortly plus a short list of known bugs. See this weeks TODO list / Release Plan posting for some details. The release notes for Xen 4.2 are still a work in progress but can be found on the wiki.

I’d like to encourage everyone to start testing now. You can get RC1 from the Xen unstable mercurial tree (in the short term the actual 4.2.0-rc1 tag will be in the staging tree until testing passes). Please report any issues which you find to the xen-devel mailing list.

In particular I would encourage everyone to test the new xl toolstack with their use cases. In Xen 4.2.0 the venerable xend toolstack will be deprecated and everyone will be encouraged everyone to move over to xl whenever possible. xl is in good shape already, has good support for the core features and is quite robust etc. However one of the factors of xend unmaintainability is that no one is quite sure what all of its features actually are! So if you suspect you are using functionality which is a bit unusual or less common then please do give xl a try and report your findings to the xen-devel mailing list so that we can attempt to resolve these issues before the 4.2.0 release.

Xen @ OSCON 2012

Rather than write a long report about what was new and exciting at OSCON this year, I will keep the event report short. Just one word: OSCON is mainly a conference for charities, companies, government and any organization that want to get an overview of what happened in open source to stay informed. This means its content covers a broad spectrum: from overviews to in-depth talks.

From my perspective, a few things were exciting at OSCON this year: finally has a proper booth that we can re-use at events, we had a 3.5 hour Xen and XCP tutorial and we had community members involved in preparing and running our event presence.

At this point, it is really time to thank them in alphabetical order: George Dunlap (Citrix),  Josh West (, Steven Maresca (Zentific LLC) and Patrick F. Wilbur (PFW Research LLC) who helped man the booth and promote our project and community. I also wanted to thank their parent organizations or employers who either allowed them to take time out to visit and a special thank you where vacation days had to be used.

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PCI Passthrough in QEMU

We now have PCI passthrough support in QEMU upstream, this was one of the missing pieces needed to have a full featured QEMU device model. But there is still more work to do on it.

Why do we use QEMU?

We use QEMU in Xen to emulate a part of the hardware, in particular a disk, a network card and the graphic output. So a guest does not need to be modified in order to run under Xen. Even with a modified guest, QEMU can be used to handle the graphic output of the guest, or as a backend for a paravirtualized disk or network card.

A blog post a year ago mentions that we had Xen support in QEMU, this was the first part needed to run a Xen guest with QEMU upstream. Now, with the PCI passthrough support upstreamed, that one large piece of code closer to a full featured QEMU upstream.

What is PCI passthrough?

Also known as device assignment, PCI passthrough is here to assign a real PCI device to a guest, like a network card or a sound card. This give full and direct access to the PCI device from a fully virtualized guest.

To use it, take a look at our wiki: PCI passthrough with Xen 4.2 as there is no change compared to the traditional qemu-dm. You can take a look here as well: Xen PCI Passthrough for more general information about PCI passthrough.

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Debconf12, Managua, Nicaragua

All of this week Ian Jackson and myself have been have been attending DebConf12 in Managua, Nicaragua. This is the annual conference of the Debian Project, hosted this year by Universidad Centroamericana.

There have already been several days of talks, including the traditional “Bits from… ” talks from the release teams, project leader, DSA team etc and interesting talks on UEFI, ARM, multiarch and cross building. In particular it was very interesting from my point of view (due to my involvement with the new Xen port to ARMv7 with hardware extensions) to see the talk on the new “aarch64” 64 bit ARM architecture. Not to mention the traditional Cheese & Wine party and the day trip. Sadly our attempt to climb Cerro Negro, the youngest volcano in Central America, was scuppered by a landslide on the road leading to the foot of the volcano.

Debian for the Cloud Track

As I write this I have just finished my Debian & Xen: Past Present and Future talk as part of the Debian for the Cloud Track. Also on this track there have been or will be talks on XCP, Ganeti, advanced Linux networking and a discussion of upstream compatiblity concerns.

All the DebConf talks are being streamed live from the venue but if you’ve missed one then they will eventually be made available for offline viewing.


As always there has been a hacklab. When I’ve not been listening to talks I’ve been doing some triage of the Xen bugs in the Debian BTS. There was quite a large number of bugs which had either already been fixed or which had become somehow irrelevant.

Unrelated to Xen I’ve also managed while I was here to implement support for the DreamPlug plug computer in the Debian Installer.

Impressions of Nicaragua

In my experience Nicaragua is an excellent place to visit, I wish I’d thought to extend my stay a bit so I could see more. Everyone I’ve met here is extremely welcoming and friendly. It’s also not nearly as hot I was expecting, although don’t get me wrong — it’s really very hot indeed. It hasn’t rained as much as I might have expected at this time of year, but when it has rained it really has taken no prisoners.

Xen Event Update, June 2012

A quick round-up of Xen events in June. We hope to meet you in person!

XenSummit, August 27-28: Agenda is published

I have just published the XenSummit event agenda. We will have 30 talks in two tracks this year. And the line-up this year looks fantastic! Check it out. Do note that there is also an invite-only Xen Developer Meeting on Sunday the 26th is invite-only. Xen Developers can request an invite.

More information on XenSummit…

DebConf 2012, July 8-14

DebConf 2012, July 8-14, Managua, Nicaragua: Members of the Xen community will be at DebConf this year. Ian Campbell, Ian Jackson and Thomas Goirand will talk about Xen and Debian: Past, Present & Future, Incompatibility and pain – a perspective from Xen upstream and Cloud Computing on Debian.

Virtual Build a Cloud Day, July 10

Virtual Build a Cloud Day, July 10: Mike McClurg, the XCP project lead will introduce the Xen Cloud Platform. You will also get lots more information about buildinbg open source clouds.

OSCON 2012, July 16-20

OSCON 2012, July 16-20, Portland, OR: The Xen and XCP teams will be at OSCON in Portland. Come to our Xen and XCP tutorial on July 17th with presentations from George Dunlap, Josh West, Patrick F. Wilbur and Steven Maresca or pop by the booth.

CloudOpen 2012, August 29-31

CloudOpen 2012, August 29-31, San Diego, Ca. Xen related talks are Virtualization in the Cloud: featuring Xen, Building FOSS Clouds (Part I), Building FOSS Clouds (Part II).