HEP Computing in a Context-Aware Cloud Environment.

This paper describes the use of a distributed cloud computing system for high energy physics (HEP) applications. The system is composed of IaaS clouds integrated into a unified infrastructure that has been in production for over two years. It continues to expand in scale and sites, encompassing more than twenty clouds on three continents. We are prototyping a new context-aware architecture that enables the virtual machines to make connections to both software and data repositories based on geolocation information. The new design will significantly enhance the ability of the system to scale to higher workloads and run data-intensive applications. We review the operation of the production system and describe our work towards a context-aware cloud system.