Speaker
I. Stokes-Rees
(UNIVERSITY OF OXFORD PARTICLE PHYSICS)
Description
The DIRAC system developed for the CERN LHCb experiment is a grid
infrastructure for managing generic simulation and analysis jobs. It
enables jobs to be distributed across a variety of computing
resources, such as PBS, LSF, BQS, Condor, Globus, LCG, and individual
workstations.
A key challenge of distributed service architectures is that there is
no single point of control over all components. DIRAC addresses this
via two complementary features:
a distributed Information System, and an XMPP (Extensible Messaging
and Presence Protocol) Instant Messaging framework.
The Information System provides a concept of local and remote
information sources.
Any information which is not found locally will be fetched from
remote sources. This allows a component to define its own state,
while fetching the state of other components directly from those
components, or via a central Information Service. We will present the
architecture, features, and performance of this system.
XMPP has provided DIRAC with numerous advantages. As an
authenticated, robust,lightweight, and scalable asynchronous message
passing system, XMPP is used, in addition to XML-RPC, for inter-
Service communication, making DIRAC very fault-tolerant, a critical
feature when using Service Oriented Architectures. XMPP
is also used for monitoring real-time behaviour of the various DIRAC
components.
Finally, XMPP provides XML-RPC like facilities which are being
developed to provide control channels direct to Services, Agents, and
Jobs. We will describe our novel use of Instant Messaging in DIRAC
and discuss directions for the future.
Primary authors
A. Tsaregorodtsev
(CPPM, IN2P3)
I. Stokes-Rees
(UNIVERSITY OF OXFORD PARTICLE PHYSICS)
V. GARONNE
(CNRS-IN2P3-CPPM, MARSEILLE)
