Tag Archives: CES

Welcome to the Xen4CentOS6 Project : First Release

CentOSLogoThe Xen4CentOS6 project is a collaborative effort between the Xen Project, the Citrix Xen development teams, the CentOS Project team, GoDaddy Cloud operations group and RackSpace Hosting to package, deliver and maintain a stable Xen hypervisor and its related tooling for CentOS-6, enabling CentOS-6/x86_64 to be used as a dom0, base platform to host Xen in paravirt and fullvirt deployment roles.

We have tried to ensure that existing tooling that users have in production written again xm/xend will continue to work, while also adding support for the newer xenlight (xl) layers. Most libvirt functions also continue to work on Xen4CentOS6 as they did on Xen3 CentOS5, enabling users to easily migrate their infra over from CentOS-5 to 6.

A second primary principle we are working against is to build and deliver a Linux Kernel based on the 3.4 LTS release, stabilised via testing, with enhanced Xen support as recommended by the Xen development team.

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Xen 4.3.0-RC1 is out!

We proudly announce that the Xen 4.3 RC-cycle has just started, with the tagging of 4.3.0-rc1 in our repository. Read the official announcement from George on xen-devel here.

A tarball has been made available for ease and speed-up testing: Xen 4.3.0 RC1 Tarball (and signature).

For more detailed instructions on how to effectively test this first release candidate, look at this Wiki page: Xen 4.3 RC1 Test Instructions.

And like if this wasn’t enough, today (Wednesday, 8th May 2013) is the first Xen Test Day for Xen 4.3, so come on #xentest (on freenode) and help us nailing nasty bugs! Further Xen Test Days are scheduled for May 22nd and June 4th.

Using xen-tools on Fedora

Xen.org blog already hosted a very nice post by Ian Jackson, greatly explaining how useful xen-tools is for automatically installing Debian (and Debian-derived) VMs. Now, if this all happens on a Debian host, it is nice and easy, as getting xen-tools is just a matter of apt-get install-ing it. But what if your host machine runs something else, for instance, a copy of Fedora? As a matter of fact, starting from Fedora 16, Xen is quite easy to install and use on Fedora, making it interesting to cover this case too.

There is no xen-tools RPM package, thus we need to go the good old way: download the sources, compile and  install them. Luckily enough, this is not difficult at all, and this blog post will explain in details how to achieve it.

Installing Fedora and Xen

So, let’s assume that you just finished installing the new and shiny Spherical Cow. Official instructions and advice on that are available here. The first thing to do now is to install Xen there. This has become very simple these days; all that’s needed is the following (where an # prompt means the command must be run as root):

# yum install xen

Followed by a reboot. Note that Xen will not be the default boot option, so you’ll need to make sure to select it from the GRUB2 menu. You can also make Xen the default by setting GRUB_DEFAULT=saved in your /etc/defaults/grub.conf and running the following:

# grub2-mkconfig -o /boot/grub2/grub.cfg
# XEN=$(grep ^menuentry /boot/grub2/grub.cfg | cut -f2 -d"'" | tail -n1)
# grub2-set-default $XEN

If the libvirt‘s services are needed too, some more packages must be installed, but this is out of the scope of this post. For more information on how to install Xen on Fedora, check the Fedora pages on Xen.org’s Wiki, in particular, this one: Fedora Host Installation.

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Xen ARM in Linux!

Last weekend Linus Torvalds pulled the Xen on ARM patches in his Linux tree, so as of Saturday the 7th of October, we have Xen ARM in upstream Linux!

This makes Xen the first hypervisor supported by Linux on the ARM platform!

Working on ARM has been a very pleasant experience for me: the documentation of the hardware is well written and complete, the virtualization extensions are useful and fit our architecture very well, the ARM emulator comes with a nice debugger that helped me figure out some of the most difficult problems I had.

But beyond the hardware and the development tools, I was really impressed by how welcoming the Linux ARM Community has been to me: from the invite to the ARM session at the Kernel Summit, to the guidance through the upstreaming process and in general the feedback I received to my work. Nowadays, the Linux Community is usually perceived as not being friendly to newcomers, but it hasn’t certainly been the case for me! In particular I would like to thanks Arnd Bergmann, Marc Zyngier, and the Linaro folks. It has been great working with you. I would also like to thank Konrad Rzeszutek Wilk because he went out of his way to help me upstream my ARM work: I couldn’t have done it without him.

As the Xen on ARM patches were pulled by Linus, I was also appointed as Xen ARM maintainer in the Linux kernel. This is a new responsibility for me and I am not going to take it lightly. I am looking forward to work closely with Arnd, Russell, Konrad and the other Linux maintainers to make Linux the best operating system to run virtual machines and inside virtual machines on Xen on ARM!

What’s next

While Xen on ARM in Linux is certainly a major milestone, there are still a lot of things to do. Right now I am busy trying to run Xen on a Cortex A15 Versatile Express development platform while Ian Campbell already started the ARMv8 Xen port!
Stay tuned if you want to run Xen 64-bit on ARM.

See Also

If you are interested in the Xen on ARM project, you might want to read the slides of the presentation I gave at XenSummit 2012:

XenSummit Videos: Xen & Apache CloudStack, Xen & OpenStack

This is another post in a series pointing you to noteworthy XenSummit presentations. This week I will be covering Xen integrations with Apache Cloudstack and OpenStack:

  • Xen and CloudStack: Ewan Mellor describes the CloudStack project and explains why Xen is the pre-eminent hypervisor in public clouds today. He describes the changes coming in CloudStack in the next 12 months, and how they are going to change the way that Xen is consumed in public and private clouds.
  • Openstack, Xen and XCP: John Garbutt takes a look at how OpenStack and Xen work together, and shows how you can get more involved.

Xen and CloudStack


Also see: Presentation

Openstack, Xen and XCP


Also see: Presentation
Related presentations: Xen Cloud Platform Update

XenSummit Sessions: New PVH virtualisation mode for ARM Cortex A15/ARM Servers and x86

This is the second blog post in a series pointing you to noteworthy XenSummit presentations. This week I will be covering seemingly unrelated topics – but you will realize they are not unrelated:

  • The new PV in an HVM container virtualization mode (or PVH) proposed and developed by Mukesh Rathor, Oracle: this is a new virtualization mode called PVH aimed to be part of Xen 4.3. PVH guests are essentially PV guests using PV drivers for boot and I/O. Otherwise it uses HW virtualization extensions, without the need for emulation. PVH has the potential to combine the best trade-offs of all Xen virtualization modes, while simplifying the Xen architecture significantly. First patches are going into xen-unstable as we speak and functionality should be at least available as a preview (but hopefully ready for prime-time) in Xen 4.3.
  • An update on the Xen on ARM port for Servers: Stefano Stabellini (Citrix) is presenting the state of his work ARM work for the Cortex A15, design goals (and what we achieved), architecture and remaining challenges. Interestingly, the approach taken for Xen on ARM is the same as Mukesh has taken for PVH. Even if you are not interested in ARM (and merely want to understand PVH a bit more), it is worth watching this session. Stefano is upstreaming remaining patches to Linux currently, and started working on testing his port on real hardware. Ian Campbell has just started porting the code to ARM v8. Stay tuned!
  • Panel on ARM Servers: Representatives from ARM, Canonical, Calxeda and Citrix discuss the potential of virtualization for ARM based servers. I added this video, to provide context for Stefano’s and Ian Campbells work.

PVH: PV Guest in HVM Container


Also see: Presentation

Xen on ARM Cortex A15

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