Dependable distributed OSGi environment

• Authors: Miguel Matos;António Sousa
• Venue: Proceedings of the 3rd workshop on Middleware for service oriented computing
• Year: 2008

As the vision of Service Oriented Computing matures the need for well defined architectures and protocols is essential. The SOC paradigm has several requirements to work properly: service composition and cooperation in a loosely coupled fashion, ability to adapt autonomously to environmental and business changes, proper integration between services, modularity and service dynamics. The OSGi[13] platform embodies key aspects of the SOC paradigm by defining a modular and dynamic architecture. However there is still room for improvement, namely on the creation of architectures and mechanisms to improve the dependability of the platform by strengthening key properties such as availability, reliability, integrity, safety and maintainability. In this paper we propose a OSGi based middleware layer that offers the strong modular and dynamic properties required in a SOC environment, while addressing dependability concerns. The starting point to achieve this is by instrumenting a OSGi implementation with means to monitor and manage it accordingly to business and environmental requirements. By relying on group communication facilities and some properties from the OSGi specification we are able to migrate OSGi environments among nodes, thus minimizing service outage in the presence of faults and addressing, at the same time, Service Level Agreement properties by migrating (or shutting down) services that are consuming more resources than agreed/expected.