Dear Community Members,
Xen.org is pleased to announce the release of Xen 4.2.0. The
release is available from the download page:
This release is the culmination of 18 months and almost 2900
commits and almost 300K lines of code of development effort, by
124 individuals from 43 organizations.
New Features
The release incorporates many new features and improvements to
existing features. There are improvements across the board
including to Security, Scalability, Performance and Documentation.
XL is now the default toolstack: Significant
effort has gone in to the XL tool toolstack in this release and it
is now feature complete and robust enough that we have made it the
default. This toolstack can now replace xend in the majority of
deployments, see XL
vs Xend Feature Comparison. As well as improving XL the
underlying libxl library has been significantly improved and
supports the majority of the most common toolstack features. In
addition the API has been declared stable which should make it
even easier for external toolstack such as libvirt and XCP’s xapi
to make full use of this functionality in the future.
Large Systems: Following on from the
improvements made in 4.1 Xen now supports even larger systems,
with up to 4095 host CPUs and up to 512 guest CPUs. In addition
toolstack feature like the ability to automatically create a
CPUPOOL per NUMA node and more intelligent placement of guest
VCPUs on NUMA nodes have further improved the Xen experience on
large systems. Other new features, such as multiple PCI segment
support have also made a positive impact on such systems.
Improved security: The XSM/Flask subsystem has
seen several enhancements, including improved support for
disaggregated systems and a rewritten example policy which is
clearer and simpler to modify to suit local requirements.
Documentation: The Xen documentation has been
much improved, both the wiki. This is in no small
part down to the success of the Xen Document
Days so thanks to all who have taken part.
You can find more information in the release
notes and feature
list on the wiki.
Upstreaming
The Xen project continues to work closely with our upstreams.
Of particular note in this release cycle is the upstreaming of
the HVM device model support into upstream qemu. After the Linux dom0 support
(merged upstream in 3.0 in the 4.1 release cycle) the qemu-derived
device model was the largest remaining piece of code which
required upstreaming. Support for Xen was merged into upstream
prior to the qemu 0.15 release and is supported as an option using
the XL toolstack. It will become the default in 4.3. Alongside
this support we have also gained support for SeaBIOS (a cleaner
and more maintainable legacy BIOS, used by default when upstream
qemu is selected) and Tianocore/OVMF (a UEFI BIOS). Support for
Xen has been merged into the upstreams of both of these projects
during the Xen 4.2 development cycle.
More Information
Links to useful wiki pages and other resources can be found on
the Xen
support page.
Thanks
Contributions were made to this release by 124 individuals from
43 organizations, and that’s not counting contributions to
external projects such as the BSDs, Linux or qemu. Many thanks to
everyone who contributed to this release, either through code,
testing, documentation or in any other way.
The diagram below shows organisations which contributed more than
1% in lines of code to the Xen 4.2 release. Several items in the
diagram discribe groups of people or organisations: Individual
covers contributions by individuals whose affiliation is unknown,
Misc covers contributions by commercial organisations
which did not go above 1% individually and University
covers contributions by Universities which did not go above 1%
individually.
I did also want to list the top 20 contributors to Xen 4.2 (in
terms of commits/and lines of code). These are:
- Jan Beulich (338 commits/40357 LOC)
- Roger Pau Monne (87/36932)
- Ian Campbell (504/32009)
- Stefano Stabellini (124/29130)
- Ian Jackson (174/27900)
- Daniel De Graaf (79/11103)
- David Vrabel (45/11075
- Tim Deegan (143/8790)
- Christoph Egger (67/8590)
- Matt Wilson (9/8508)
- Andrés Lagar-Cavilla (115/8050)
- Keir Fraser (143/5593)
- Wei Wang (34/5577)
- Anthony Perard (45/5289)
- Olaf Hering (154/4296)
- Qing He (20/4179)
- George Dunlap (75/4088)
- Dario Faggioli (30/3742)
- Shriram Rajagopalan (21/3481)
- Jonathan Davies (3/3230)
For a complete breakdown see the Acknowledgement
page. A big thank you again!
Best Regards
Lars
