Usher: An Extensible Framework for Managing Clusters of Virtual Machines
Source: University of California
Usher is a virtual machine management system designed to impose few constraints upon the computing environment under its management. Usher enables administrators to choose how their virtual machine environment will be configured and the policies under which they will be managed. The modular design of Usher allows for alternate implementations for authentication, authorization, infrastructure handling, logging, and virtual machine scheduling. The design philosophy of Usher is to provide an interface whereby users and administrators can request virtual machine operations while delegating administrative tasks for these operations to modular plugins.