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VCLab on the GRID. Piotr Szczytowski , RUB. Tutorial overview. Introduction to VCLab Non GRIDified VCLab presentation Design of new architecture – from Web Services to GRID services GRID aware VCLab presentation Implementing GRID services Web Service -> OGSI-> GrASP Encountered problems
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VCLab on the GRID Piotr Szczytowski, RUB
Tutorial overview • Introduction to VCLab • Non GRIDified VCLab presentation • Design of new architecture – from Web Services to GRID services • GRID aware VCLab presentation • Implementing GRID services • Web Service -> OGSI-> GrASP • Encountered problems • Conclusions VCLab on the GRID
Introduction to VCLab VSE 1 VSE 2 VSE n VCLab on the GRID
Virtual Scientific Experiments VSE Visualization Simulation Service 3D Environment Computation Service Interaction Collaboration Service Client GRID VCLab on the GRID
Old VCLab Architecture • Matlab running locally • NPVCLab – scriptable plug-in for interfacing Matlab • Results form simulation returned by local socket connection • Simulation and VRML files delivered form web site VCLab on the GRID
Non GRIDified VCLab VCLab on the GRID
VCLab as WebServices based application Computation Web Service Browser VCLab WebApplication DataSupply Web Service VCLab on the GRID
WebServices oriented VCLab VCLab on the GRID
Implementation task for making VCLab GRID aware • NPVCLab plug-in reimplemented as COM object, each instance of object represents one instance of Matlab • Implementation of Computation Engine Proxy Server • Functionality of Matlab Engine exposed as Computation Service • File upload, download and querying implemented as DataSupply Service • Implementing customized FactoryService • HotAnim applet reimplemented as VRMLProxy ActiveX and HotWS/OGSI • Access to VRML scene through JavaScript or in case of Mozilla family browser through NPHot2VRML plug-in VCLab on the GRID
Transition to new architecture VCLab as an application consist of Server side: • Compuation Service • DataSupply Service • GrASP • Web Application Client side: • VRML scene • VRMLProxy / HotOGSI VCLab on the GRID
How does it work? OGSI Computation Service Computation Service Factory OGSI Computation Service Browser VCLab WebApplication GrASP Gateway OGSI DataSupply Service DataSupply Service Factory VCLab on the GRID
GRID aware VCLab presentation VCLab on the GRID
Implementing GRID Servicepractical example Implementation steps: • Creating service logic as Web Services and debugging. • Changing Web Service to OGSI service • Implementing communication with OGSI container and testing. • Extending OGSI service into GrASP service • Implementing communication between application and GrASP subsystems (Instantiation Service) VCLab on the GRID
Encountered problems Implementation related problems: • Matlab engine instantiation problem • C++ and Java Client problem GRID related problems: • GrASP response time problem • GrASP fault non recovery problem • OGSI.NET time zones problem DataSupply Service related problems • User authorization problem • Data consistency among DataSupply services problem VCLab on the GRID
Implementation related problems Matlab engine instantiation problem • Limited amount of instance when running created within Windows Service • Solved by creating standalone Proxy application C++ and Java Client problem • Missing support for OGSI services in Java and C++ • Solved by implementing own SOAP based communication VCLab on the GRID
GRID related problems GrASP response time problem • Response time linear dependent from amount of implemented methods by service • Temporary solution: disabling Accounting service GrASP fault non recovery problem • Existence of not responding host, prevents other host from rejoining GRID OGSI.NET time zones problem • OGSI container controls validity of calls using local time instead of UTC VCLab on the GRID
DataSupply Service related problems User authorization problem • For adding and deleting simulation authorization is required • Implemented as independent service • Implemented using GrASP subsystem Data consistency among DataSupply services problem • Data synchronization between instances of DataSupply services • Data replication strategy VCLab on the GRID
Conclusions • Reimplementing application to GRID aware version may be generalized to problem of creating Web Services and “decorating” them with OGSI/GrASP porttypes • Several no critical problems were discovered • Prototype implementation accessible at http://quack.atp.rub.de/grid%20vclab VCLab on the GRID