Different experiments use different systems to manage their Grid jobs. The Distributed Infrastructure with Remote Agent Control (DIRAC) solution was developed as a workflow management and data management system for the LHCb experiment but is now used by many smaller Virtual Organisations (VOs). DIRAC consists of many cooperating services and lightweight agents delivering the complex data processing and simulation workloads to the worldwide Grid fabric.
DIRAC was the first system in particle physics to use the pilot agent paradigm, whereby, prior to submitting batch jobs to Grid worker nodes, a so-called pilot job is first submitted. This pilot job checks that the local environment is correctly configured and has the necessary resources before pulling the real workload onto the node. This has been demonstrated to be essential to achieve high success rates and high efficiency across a heterogeneous Grid.
The GridPP DIRAC service is a DIRAC instance hosted at Imperial College London that has been developed to cater for the multiple VOs that represent the non-LHC users of GridPP resources. In combination with the Ganga software suite, a Python-based user interface for client-side grid job management, users have at their disposal a powerful set of tools for managing complex distributed computing workflows.