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

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

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

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

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

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

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

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

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

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

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

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

Questions?
Xen Summit at AMD
April 28­29, 2010