Towards the Design of a Scalable Business Process Management System Architecture in the Cloud

The ubiquity of cloud computing is shifting the deployment of Business Process Management Systems (BPMS) from traditional on-premise models to the Software-as-a-Service (SaaS) paradigm, thus aiming to deliver Business Process Automation as a Service to multiple tenants in the cloud. However, scaling up a traditional BPMS to cope with simultaneous demand from multiple organisations in the cloud is challenging, since its underlying system architecture has been designed to serve a single organisation with a single workflow engine. A typical SaaS often deploys multiple instances of its core applications and distributes workload to these application instances via load balancing. But, for stateful and often long-running process instances, standard stateless load balancing strategies are inadequate. In this paper, we propose a conceptual design of a scalable system architecture for deploying BPMS in the cloud. In our design, Object Role Modeling (ORM) is used to conceptualise the data requirements of the system and UML sequence diagrams are used to capture the interactions between system components. A prototypical implementation using an open-source traditional BPMS offers focused load balancing strategies and demonstrates improved capabilities for supporting large volumes of work in a multi-tenanted cloud environment.