A decentralized mechanism for application level monitoring of distributed systems

For a complex distributed system to be dependable, it must be continuously monitored, so that its failures and imperfections can be discovered and corrected in a timely manner. This work is concerned with the monitoring of large, open and heterogeneous systems, at their application level. Our objective is a monitoring technique that satisfies the following properties: scalability with respect to the size of the system and with the complexity of the monitoring task; the ability to deal reliably with heterogeneous components; and the ease and flexibility of deployment. Our approach to monitoring is based on a middleware called law-governed interaction (LGI), which is a decentralized coordination and control mechanism.