Karesansui is an open-source virtualization management application made in Japan. It's smart graphical user interface lowers your management cost, and brings a total management/audit solution for both physical and virtual servers. Full featured RESTful interface allows customizing and integration with other management/billing systems.
Canopsis is the first Open Source Hypervisor. It's built on top of existing monitoring solutions (Shinken, Nagios, Syslog)… Its goals is to correlate events from those solutions and fills the gap between technical monitoring and business monitoring.