Dynamic Reconfiguration and Virtual Machine Management in the Harness Metacomputing System

Metacomputing frameworks have received renewed attention of late, fueled both by advances in hardware and networking, and by novel concepts such as computational grids. However these frameworks are often inflexible, and force the application into a fixed environment rather than trying to adapt to the application’s needs. Harness is an experimental metacomputing system based upon the principle of dynamic reconfigurability not only in terms of the computers and networks that comprise the virtual machine, but also in the capabilities of the VM itself. These characteristics may be modified under user control via a "plug-in" mechanism that is the central feature of the system. In this paper we describe how the design of the Harness system allows the dynamic configuration and reconfiguration of virtual machines, including naming and addressing methods, as well as plug-in location, loading, validation, and synchronization methods.