Process-based Software Tweaking with Mobile Agents

We describe an approach based upon software process technology to on-the-fly monitoring, redeployment, reconfiguration, and in general adaptation of distributed software applications, in short 'software tweaking'. We choose the term tweaking to refer to modifications in structure and behavior that can be made to individual components, as well as sets thereof, or the overall target system configuration, such as adding, removing or substituting components, while the system is running and without bringing it down. The goal of software tweaking is manifold: supporting run-time software composition, enforcing adherence to requirements, ensuring uptime and quality of service of mission-critical systems, recovering from and preventing faults, seamless system upgrading, etc. Our approach involves dispatching and coordinating software agents - named Worklets - via a process engine, since successful tweaking of a complex distributed software system often requires the concerted action of multiple agents on multiple components. The software tweaking process must incorporate and decide upon knowledge about the specifications and architecture of the target software, as well as Worklets capabilities. Software tweaking is correlated to a variety of other software processes - such as configuration management, deployment, validation and evolution - and allows to address at run time a number of related concerns that are normally dealt with only at development time