ReLoC: A Resilient Loosely Coupled Application Architecture for State Management in the Cloud

Abstract

Maintaining the state of applications and user sessions is difficult in large scale web-based software systems. This problem is particularly accentuated in the context of Cloud computing as Cloud providers, especially Platform as a Service (PaaS) vendors, do not explicitly support state management infrastructure - such as clustering. In a PaaS environment, a user has little or no access and control over the server platform and session management layer. Additionally, the platform tiers are generally loosely coupled and service-oriented. These make traditional session-state management techniques non-usable. In this work, we present ReLoC - a session-state management architecture for Cloud that uses loosely-coupled services and platform agnostic scalable messaging technology to propagate and save session states. Preliminary experiments show a very high level of tolerance to failures of the platform tiers without corresponding disruptions in user sessions. We argue that, in the context of PaaS Clouds, ReLoC architecture will be more scalable compared to traditional clustering environments.