Grid-Enabled Interactive Air Pollution Simulation for European Research Area

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Remote Access Server Computing Element Migrating Desktop Worker node 0 Worker node 1 … Worker node N int.eu.grid project • Objectives • deployment and operation of an advanced Grid empowered infrastructure in the European Research Area specifically oriented to support the execution of interactive demanding applications • promotion of the use of this Grid-empowered European infrastructure based on powerful clusters through an advanced network • guaranteeing interoperability with existing large e-Infrastructures like EGEE by providing basic common middleware services • Provision of • Distributed Parallel (MPI) Interactive Computing and Storage at the Tera level • User Friendly Access through a Grid Interactive Desktop with powerful visualization • Support to Virtual Organizations at all levels: • Setup • Collaborative environment • Grid enhancement of applications • Execution and monitoring tools The consortium involves 13 leading institutions in 7 countries, with significant computing capacity and expertise in grid technology. Job control Interactive channels User’s machine CrossBroker JDL Job Submission Services Gatekeeper gLogin Interactive input LRMS Interactive output Grid Interactive Air Pollution Simulation in int.eu.grid • Branislav Šimo1, Viera Šípkova1, Martin Gažák2, Ladislav Hluchý1 • 1) Institute of Informatics, Slovak Academy of Sciences • 2) MicroStep-MIS • Contact: branislav.simo@savba.sk Interactivity in general • A data channel is created between the application running in the grid and a special application specific plug-in running inside the Migrating Desktop. • The channel passes all the data from the standard output of the application to the plug-in and data sent to the channel are passed to the standard input of the application. • MPI: The channel takes output from all job’s MPI processes; input is connected to the master process only. • To avoid firewall problems, the interactive channel data is forwarded via an intermediate server – Roaming Access Server. IMS Model Suite • Environmental Dispersion Modeling using Lagrangian Trajectory Model. • Complex commercial software system for prediction of the consequences of environmental pollution, nuclear accident or other emergence. • Numerical modeling of phenomena: • Continuous or short-term releases of multiple simultaneous pollutant species • Dispersion of multiple pollutants • Atmospheric transport and diffusion under changing weather conditions • Deposition (wet, dry) • Radioactive decay • Pre-defined scenarios • Initially a sequential model running on Windows OS. • Computational time increases with raising number of simulated particles.Individual particles are independent of each other. The implementation Interactive steering of a simulation running on the grid: • The Migrating Desktop UI is used as a platform for submitting the application to the grid and launching the application specific interaction plug-in. • User can submit the application using the predefined parameters stored as an icon on the desktop. One of the parameters specifies the use of interactive channel. • When the job enters running state the user starts the application plug-in, which connects via interactive channel to the application. • As the computation proceeds, images showing map with the particles are sent to the user for each hour of simulation time (i.e. every few seconds). Images are buffered locally to enable viewing past images and for playing simple animation. • Each simulation step, the user can send a command to split particles, thus doubling particle count simulated. There is also a command for terminating the simulation correctly instead of aborting it the usual way. • Textual debugging and informative messages generated by the application are also transferred via the interactive channel. • Interactive application allows users to view the development of the simulation in real-time, influence the simulation interactively and see the immediate results of their actions. Gridification and interactivity • Reimplementation of some of the functionality of Borland C++ Builder libraries to make it compile on Linux. • Creation of wrapper scripts for set-up of application environment. • MPI parallelization. Particles are divided among MPI processes. • Modification for interactive channel: Images and messages multiplexed into stdout; stdin is monitored for commands from user. • Implementation of application plug-in for Migrating Desktop that is used for communication with application. Int.eu.grid tools used • gLogin • Creates interactive channel between grid node(s) and user’s machine • Based on SSH with GSI • Migrating Desktop • Java client GUI wrapping various grid tools (security, data management, job management). Supports plug-ins (OSGI architecture, like Eclipse) • Application specific plug-in can be created to handle the data flowing to/from the interactive channel Project reference: int.eu.grid - EU 6FP Interactive European Grid project, 2006-2008, contract no. 031857 Web: www.interactive-grid.eu