Libxenlight is a C library that provides a simple API for toolstacks like Xend and Libvirt to perform Xen operations. It aims to consolidate the code for different toolstacks, which currently have duplications and inefficiencies. Libxenlight follows design principles like being stateless and hiding lower-level Xen components. A new toolstack called XL has also been created with the goals of being small, tested and compatible with xm commands while using Libxenlight. Multiple toolstacks may be ported to use Libxenlight and its development is open to contributions.

1. LIBXENLIGHT
Stefano Stabellini
Xen Summit at AMD
April 28­29, 2010

2. The current situation
Multiple toolstacks:
­ Xend, Xapi, XenVM, LibVirt, ...
­ code duplications, inefficiencies, bugs, wasted
efforts
Xend:
­ difficult to understand, modify and extend
Xen Summit at AMD
April 28­29, 2010

3. The solution: libxenlight
What is Libxenlight:
­ a small lower level library in C
­ simple to understand
­ easy to modify and extend
Goals:
­ provide a simple and robust API for toolstacks
­ create a common codebase to do Xen operations
Xen Summit at AMD
April 28­29, 2010

4. The current architecture
Xen Summit at AMD
April 28­29, 2010

5. The new architecture
Xen Summit at AMD
April 28­29, 2010

6. Libxenlight: design principles
­ implement mechanisms, not policies
­ stateless
­ hide xenstore, libxenctrl and libxenguest from
the higher levels
­ be as simple as possible
Xen Summit at AMD
April 28­29, 2010

7. XL: not just unit testing
­ the unit testing tool for libxenlight
­ feature complete
­ a minimal toolstack
­ 99% compatible with xm
do more with less!
Xen Summit at AMD
April 28­29, 2010

8. XL: design principles
­ smallest possible toolstack on top of libxenlight
­ stateless
­ work without any additional daemons
CLI → XL → Libxenlight → EXIT
exception: domain cleanup, cdrom eject
Xen Summit at AMD
April 28­29, 2010

9. The new architecture: adding XL
Xen Summit at AMD
April 28­29, 2010

10. XL vs. Xend
XL: pros
­ very small and easy to read
­ well tested
­ compatible with xm
Xend: pros
­ provide XML RPC interface
­ provide ”managed domains”
Xen Summit at AMD
April 28­29, 2010

11. TODO list
­ implement missing features
­ make libxenlight rock solid
­ port xend on top of libxenlight
­ port xapi on top of libxenlight
­ port libvirt on top of libxenlight
Xen Summit at AMD
April 28­29, 2010

12. Libxenlight: patches are welcome
­ new features should be implemented in
libxenlight
­ a hook in xl is required for testing purposes
­ bindings for xend, xapi and other toolstacks are
welcome but not required
Xen Summit at AMD
April 28­29, 2010

13. Questions?
Xen Summit at AMD
April 28­29, 2010