LibVirt is a toolkit to interact with the virtualization capabilities of recent versions of Linux (and other OSes), see our project goals for details. We are working on implementation of driver for Virtuozzo. Virtuozzo driver (former Parallels driver) is able to manage containers as well as virtual machines and available in LibVirt since release 0.10.0 (August 29 2012).
The driver is fully functional despite the fact in doesn't implement all LibVirt API calls. See status of supported API calls by Parallels driver.