Dynamic reconfiguration of Corba-based applications

Distributed applications are prone to drastic evolution during their lifetime due to user requirements, technological changes or modification of the execution environment. Application evolutions involve changes related to: (1) the application architecture, (2) the software implementation or (3) the physical location, of software components in a distributed environment during the application execution. Coping with such changes is recognized as being a difficult issue because new features must be integrated in existing applications at minimal cost and with minimal perturbation. We have designed an original algorithm for dynamic application reconfiguration, which fulfills the above requirements and we have implemented a prototype of this algorithm in a Corba environment. This prototype extends the current Corba programming model by introducing a framework for configurable object programming. The algorithm allows reconfiguration operations, such as the replacement, migration or dynamic rebinding of components. Our tools demonstrate that it is possible to reconfigure an application with minimal perturbation.