The Xen virtual machine monitor
For Linux (and NetBSD, FreeBSD) virtualization, we believe Xen offers
a solution that provides excellent stability, performance, security,
and control over resource usage. We hope to see Xen become the
de-facto standard for open source virtualization.
Xen Development Roadmap
The development roadmap for the xen project is on the project
In addition to the stable series, Xen is being used by a number of
research projects which are investigating the opportunities provided
by high-performance virtualization. These projects provide an ideal
way to try out new features, but probably won't intercept the stable
series roadmap for some time.
- Deterministic replay. Running in a virtual machine, it
becomes possible to record lightweight checkpoints of guests OSes as
they run, and log incoming events and interrupts. Thus, execution can
be rolled back and replayed in a deterministic fashion. This is great
for debugging, and can also be used to run two systems in lock-step to
provide software fail-over.
- Shared buffer-cache and VM 'forks'. We have plans to
investigate CoW memory sharing between VMs, as this can be useful for
supporting large numbers of VMs e.g. in 'honeypot'
applications. 'Forking' VMs could also be useful e.g. when starting a
web browser applet that you want to ensure can't commit to persistent
- Multi-level secure Xen. Virtual machine monitors can have
an important role to play in building multi-level secure systems. For
example, one could use one VM for accessing a corporate network while
browsing the web on another. A Mandatory Access Control system could
be used to mediate the flow of data between the two.
- I/O interposition. The virtual I/O devices can easily be
modified to simulate delay and loss, thus enabling a whole distributed
system to be emulated in a virtual environment. Combined with
deterministic replay this should result in a great tool for debugging
Contributing to Xen
Xen is a community project, benefiting from code and support
contributions from individuals and corporations around the world.
The xen-devel list is the forum for design debate and discussion of
We'd be very happy to hear from experienced kernel programmers who'd
like to join the core Xen development team.
Research funding is always appreciated too! ;-)
Thanks for your support,
The Xen team.