Distributed cloud computing in high energy physics

Cloud computing is increasingly being used for running high energy physics (HEP) applications. We review the motivation for using clouds in HEP and describe how they are gradually being integrated into our systems. In particular, we highlight our use of a distributed cloud computing system that integrates both private and public IaaS clouds into a unified infrastructure. We describe our experience using the distributed cloud and our plans to make the system context-aware in order to scale to larger workloads and run data-intensive HEP applications.