Author Archives: Lars Kurth

About Lars Kurth

Lars Kurth is a highly effective, passionate community manager with strong experience of working with open source communities (Symbian, Symbian DevCo, Eclipse, GNU) and currently is community manager for Lars has 9 years of experience building and leading engineering teams and a track record of executing several change programs impacting 1000 users. Lars has 16 years of industry experience in the tools and mobile sector working at ARM, Symbian Ltd, Symbian Foundation and Nokia. Lars has strong analytical, communication, influencing and presentation skills, good knowledge of marketing and product management and extensive background in C/C , Java and software development practices which he learned working as community manager, product manager, chief architect, engineering manager and software developer. If you want to know more, check out Personally, Lars has a wide range of interests such as literature, theatre, cinema, cooking and gardening. He is particularly fascinated by orchids and carnivorous plants and has built a rather large collection of plants from all over the world. His love for plants extends into a passion for travel, in particular to see plants grow in their native habitats.

ARM hosts Xen Project Hackathon, April 18-19 in Cambridge, UK

I am pleased to announce the next Xen Project Hackathon. The Hackathon will be hosted by ARM in their Cambridge Headquarters from April 18 and 19. I wanted to thank Philippe Robin and Thomas Molgaard from ARM for hosting the Hackathon.

ARMARM designs technology that is at the heart of advanced digital products and has built a broad partner community that increasingly embraces an open source and collaborative development model to keep pace with transitions in the industry. Enabling developer collaboration on open source projects, like Xen, is key to help optimize support for system virtualization. ARM is pleased to host and support this event.

What to expect at a Xen Project Hackathon?

The aim of the Hackathon is to give developers the opportunity to meet face to face, to discuss development, coordinate, write code, and collaborate with other developers. And, of course, the event will allow everyone to meet in person and build relationships. To facilitate this, we will have a social event on the evening of the 18th. We will cover many hot topics such as the latest Xen Project Hypervisor 4.7 features, planning for the next Xen Project Hypervisor release, Cloud Integration, Cloud Operating Systems, Mirage OS as well as Xen Project in emerging segments such as embedded, mobile, automotive and NFV. But, at the end of the day, the community will chose the topics that are covered — more on our process here below.

To ensure that the event runs efficiently, we adhere to the following process: Each day is divided into several segments. We will have a number of work areas that are labelled with numbers (or other unique identifiers). Each morning starts with a plenary and scheduling session. Every attendee who cares about a topic can announce a topic, which we will map against a work area and time-slot. This makes it easy for other attendees to participate in projects and discussions they care about. We also encourage attendees to highlight projects they plan to share before the event by adding them to our wiki.

We will wrap up each day with another short plenary session: the aim of this session is to summarize what was done, show brief demos and make improvements to the process.

To give you a sense of the venue, we attached a few pictures of the venue:

ARM Cambridge Arm Cambridge Panorama ARM Cambridge Atrium

How to Register?

As spaces at the Xen Project Hackathon are limited, we are asking attendees to request an invitation. You will need to cover your own travel, accommodation and other costs such as evening meals, etc. We do have a very limited number of travel stipends available for individuals who cannot afford to travel. Please contact community dot manager at xenproject dot org if you need to make use of it.

Reports from Previous Hackathons

More Information

Xen Project Contributor Training v2

Two weeks ago, I embarked onto a road trip to China with the aim to meet Xen Project users as well as contributors. I visited a number of vendors in Hangzhou and Beijing on this trip. Part of the objective was to give training to new contributors and developers, and to strengthen existing relationships.

Hypervisor contributions from Chinese developers

Hypervisor contributions from Chinese developers

A year ago I travelled to China and pioneered our developer training, because many of our Chinese developers had some challenges working with the community. The good news is that the training activities have helped, which can be seen in contribution statistics. This leads us to the “bad news”: a new group of developers joined the community, who could benefit from training. In addition, a lot of process and operational changes are currently discussed or have recently taken place within our community.

What is remarkable, is that many of the latest contributors to the project have only recently graduated from University (in 2014 or 2015). Working with the Xen Project and Linux was often their first experience with open source. Working with open source projects is not always easy, in particular when doing so in a non-native language and with a manager behind you, who expects that you get a feature into an open source project by a certain time. In addition, as a community we need to balance the needs of different stake-holders (enterprise, cloud, embedded, security companies) and make informed decisions on the relative importance of new features vs. quality vs. security vs. … which has led to increasingly strict criteria and more and more scrutiny, when reviewing code contributions. This means, that contributing to the project for the first time can sometimes feel like a real challenge. Part of the reason why I regularly travel to China, is to explain what is happening in the community, to explain that all members of the community can influence and shape how the project is run and to understand local community issues and address them as they occur.

Contributor Training v2

Since the creation of the training material last autumn, there have been a few changes in how the project operates. Most notably in the Security Vulnerability Management Process and Release Management. Many other areas of how the project operates are also being reviewed and discussed. The goals behind these discussions and proposed changes intend …

  • to make the communities’ development processes more efficient and scalable.
  • to make conscious decisions about trade-offs, such ease of feature contribution vs. quality and security.
  • to make it easier for newcomers to join the project.
  • to encourage more contributors to review other people’s code, test our software, write test code and make other non-code contributions to the project.

Thus, I updated our training material to reflect these changes and added new material. It is divided into 4 separate modules, each of which takes approximately 2.5 hours to deliver. The training decks are designed as reference material for self-study. Each training module has many examples and embedded links in it. The material is available from our Developer Intro Portal as slides or as PDFs. I embedded the updated and new training modules into this blog for your convenience:

If you have any questions, feel free to ask by contacting me via community dot manager at xenproject dot org and I will improve the material based on feedback. My plan is to keep the training material up-to-date and to modify it as new questions and new challenges arise.

Xen Project 4.5.2 Maintenance Release Available

I am pleased to announce the release of Xen 4.5.2. Xen Project Maintenance releases are released roughly every 4 months, in line with our Maintenance Release Policy. We recommend that all users of the 4.5 stable series update to this point release.

Xen 4.5.2 is available immediately from its git repository:;a=shortlog;h=refs/heads/stable-4.5
    (tag RELEASE-4.5.2)

or from the Xen Project download page at

This release contains many bug fixes and improvements. For a complete list of changes in this release, please check lists of changes on the download page.

Xen Project Participates in Round 11 of Outreachy

This is a quick reminder that the Xen Project is again participating in Outreachy (Round 11). Please check the round 11 page for more information about the December 2015 to March 2015 round of interships.

Outreach Program for Women has been helping women (cis and trans), trans men, and genderqueer people get involved in free and open source software worldwide. Note that the program has been extended and now also targets people from more groups underrepresented in FOSS: specifically the program is open to residents and nationals of the United States of any gender who are Black/African American, Hispanic/Latin, American Indian, Alaska Native, Native Hawaiian, or Pacific Islander.

Round 11 of Outreachy

The application deadline for interns is November 2, 2015. For a list of projects for interns and more information on how to apply, check our Xen Project Outreachy portal.

We have many different projects in many different areas! Check out the following table, which lists projects covering

  • Hypervisor Development (requiring Linux/BSD, C, scripting skills – there is also a Windows related project)
  • Mirage OS Development (requiring Linux/BSD, OCaml or Functional programming skills)
  • A Xen Code Review Dashboard project (requiring SQL, Javascript, HTML5 skills)

Learn about the Experience of past Applicants

At the 2014 Xen Project Developer Summit, we ran a panel discussion that included OPW interns, GSoC students as well as mentors.

You may also want to read Women interns rocking open source at Xen Project.

Looking forward to hear from you!

Event Report: Xen Project Developer Summit 2015

This year’s Xen Project Developer Summit is over! We had two days packed with highly technical sessions that were attended by 120 delegates. Our sessions have – as always – been very interactive with lots of discussions during and after the talks. Of course we did also have lots of time for in-corridor conversations during breaks, which most of us look forward to every year.


Andrew Cooper from Citrix is giving an introduction of Migration v2 in Xen 4.6. Check out the PDF and video.

Session Recordings and Slides

Most of the slides are already available as PDFs on the event website. We will re-post the slides later on our slideshare channel and on the Xen Project Website.

Video recordings of the conference sessions are already posted on our youtube channel and will also be posted on the Xen Project Website. Check out some of my personal highlights:

Security: xSplice – Live Patching the Xen Hypervisor

by Konrad Rzeszutek Wilk, Oracle

Other security, robustness and QoS related talks that are worth checking out are

User Stories: Virtualizing the Locomotive: Ready, Set, Go!

by Mark Kraeling, GE Transportation
A great Xen and Virtualization user story showing how Xen and Virtualization is used in extreme circumstances.

Other user stories that are worth checking out are

Hardware Support: ARM Virtualization Extensions

by Marc Zyngier & Thomas Molgaard, ARM Ltd

You may also want to check out the following talks covering new hardware features on Xen:

Xen and OpenStack

by Stefano Stabellini, Citrix

You may also want to check out the following feature update talks:

For more recordings check out our youtube channel!

Joint KVM and Xen Hackathon and Social Event

The joint activities between Xen and KVM have also been a great success, bringing developers from both communities more closely together. In particular the joint social event was a great success. I overheard many constructive conversations among members of both communities. In some cases, members of both communities were competing with each other in the bowling alley and playing pool: who said that a little bit of friendly competition can’t be fun (-: We will work with the organisers of KVM Forum such that we can build on this cooperation next year.

Xen Project 4.4.3 Maintenance Release is Available

I am pleased to announce the release of Xen 4.4.3. We recommend that all users of the 4.4 stable series update to this latest maintenance release.

Xen 4.4.3 is available immediately from its git repository:;a=shortlog;h=refs/heads/stable-4.4
    (tag RELEASE-4.4.3)

or from the Xen Project download page at

This release contains many bug fixes and improvements. For example:

  • A number of bug fixes that affected libvirt, in particular when used with OpenStack (this release contains all changes that we use in the Xen Project OpenStack CI loop; also see related OpenStack news, Latest News on Xen Support in libvirt & Xen and OpenStack);
  • Stability improvements to CPUPOOL handling, in particular when used with different schedulers;
  • Stability improvements to EFI support on some x86 platforms;
  • Security fixes since the release of Xen 4.4.2

For a complete list of changes in this release, please check lists of changes on the download page.