Secure Dynamic Reconfiguration of Scalable CORBA Systems with Mobile Agents

As various Internet services, electronic commerce, and information and communication systems permeate our lives, their continual availability becomes a dominant issue. But continuing software evolution requires system reconfiguration. Running systems must upgrade their components or change their configuration parameters. In addition, Internet services often need to serve thousands or millions of users. This scenario raises three conflicting issues that need to be resolved: availability, configurability, and scalability. We propose the use of mobile reconfiguration agents for the efficient, secure, and scalable dynamic reconfiguration of Internet systems. In our system, the agents are deployed within the object-oriented architecture of a CORBA-compliant ORB that supports safe reconfiguration both of its middleware engine and of user applications. Using a graphical front-end, administrators build reconfiguration agents and specify the topology of the reconfiguration network the agents traverse to reconfigure the distributed system on-the-fly. The agents collect, group, and return the results of inspection and reconfiguration operations in the distributed system to the administrator. Our infrastructure provides an efficient way of supporting secure dynamic reconfiguration of long-running, scalable Internet systems based on CORBA. This paper discusses our motivation, application scenarios and the design and implementation of our system. We conclude with performance results and directions for future work.