What is XAPI?
A. An extension of libvirt which adds live migration of virtual servers between arbitrary hypervisors.
B. A ReSTful API which is used by xl to communicate with the Xen hypervisor.
C. The communication interface between a paravirtualized Linux Kernel and the Xen hypervisor.
D. A high level tool chain which provides advanced management tools and interfaces for Xen.
E. The internal messaging system within the Xen hypervisor.