BeesyBees - efficient and reliable execution of service-based workflow applications for BeesyCluster using distributed agents

The paper presents an architecture and implementation that allows distributed execution of workflow applications in BeesyCluster using agents. BeesyCluster is a middleware that allows users to access distributed resources as well as publish applications as services, define service costs, grant access to other users and consume services published by others. Workflows created in the BeesyCluster middleware are exported to BPEL and executed by agents in a distributed environment. As a proof of concept, we have implemented a real workflow for parallel processing of digital images and tested it in a real cluster-based environment. Firstly, we demonstrate that engaging several agents for distributed execution is more efficient than a centralized approach.We also show increasing negotiation time in case of too many agents. Secondly, we demonstrate that execution in the proposed environment is reliable even in case of failures. If a service fails, a task agent picks a new equivalent service at runtime. If one of task agents fails, another of remaining agents takes over its responsibilities. The communication between the middleware, agents and services is encrypted.