The Grid approach for the HEP computing problem

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The Grid approach for the HEP computing problem

• Massimo Sgaravatto
• INFN Padova
• massimo.sgaravatto_at_pd.infn.it

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What is a Grid ?

• Dependable, consistent, pervasive access to
  resources
• Enable communities (virtual organizations) to
  share geographically distributed resources as
  they pursue common goals in the absence of
  central control, omniscience, trust
  relationships
• Make it easy to use diverse, geographically
  distributed, locally managed and controlled
  computing facilities as if they formed a coherent
  local cluster

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What does the Grid do for you?

• You submit your work
• And the Grid
• Partitions your work into convenient execution
  units based on the available resources, data
  distribution, if there is scope for parallelism
• Finds convenient places for it to be run
• Organises efficient access to your data
• Caching, migration, replication
• Deals with authentication and authorization to
  the different sites that you will be using
• Interfaces to local site resource allocation
  mechanisms, policies
• Runs your jobs
• Monitors progress
• Recovers from problems
• Tells you when your work is complete

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• Grid approach in many sciences and disciplines

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Mathematicians Solve NUG30

• Looking for the solution to the NUG30 quadratic
  assignment problem
• An informal collaboration of mathematicians and
  computer scientists
• Condor-G delivered 3.46E8 CPU seconds in 7 days
  (peak 1009 processors) in U.S. and Italy (8 sites)

14,5,28,24,1,3,16,15, 10,9,21,2,4,29,25,22, 13,26,
17,30,6,20,19, 8,18,7,27,12,11,23
MetaNEOS Argonne, Iowa, Northwestern, Wisconsin
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Network for Earthquake Engineering
Simulation

• NEESgrid national infrastructure to couple
  earthquake engineers with experimental
  facilities, databases, computers, each other
• On-demand access to experiments, data streams,
  computing, archives, collaboration

NEESgrid Argonne, Michigan, NCSA, UIUC, USC
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• Grid approach to address the High Energy Physics
  (HEP) computing problem

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HEP computing characteristics

• Large numbers of independent events to process
• Large data sets, mostly read-only
• Modest floating point requirement
• Batch processing for production selection -
  interactive for analysis
• Commodity components are just fine for HEP
• Very large aggregate requirements computation,
  data
• The LHC challenge
• Jump in orders of magnitude wrt. previous
  experiments
• Geographical dispersion of people and of
  resources
• Scale
• Petabytes per year of data
• Thousands of processors
• Thousands of disks
• Terabits/second of I/O bandwidth
• Complexity
• Lifetime (20 years)

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World Wide Collaboration ? distributed
computing storage capacity
CMS 1800 physicists 150 institutes 32 countries
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Solution?

• Regional Computing Centres
• Serve better the needs of the world-wide
  distributed community
• Data available nearby
• Reduce dependence on links to CERN
• Exploit established computing expertise
  infrastructure in national labs, universities
• See http//www.cern.ch/monarc

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Grid as a possible approach

• Various technical issues to address
• Resource Discovery
• Resource Management
• Distributed scheduling, optimal co-allocation of
  CPU, data and network resources, uniform
  interface to different local resource managers,
  
• Data Management
• Petabyte-scale information volumes, high speed
  data moving and replica, replica synchronization,
  data caching, uniform interface to mass storage
  management systems,
• Automated system mgmt techniques of large
  computing fabrics
• Monitoring Services
• Security
• Authentication, Authorization
• Scalability, Robustness, Resilience
• ? Grid model to address such problems

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State (HEP-centric view) circa 2.5 years ago

• Globus project
• Globus toolkit core services for Grid tools and
  applications (Authentication, Information
  service, Resource management, etc)
• Good basis to build on but
• No higher level services
• Handling of lots of data not addressed
• No production quality implementations
• Not possible to do real work with Grids yet

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DataGrid Project (EDG)

• Project started Jan 2001, duration 3 years
• Goals
• To build a significant prototype of the LHC
  computing model
• To collaborate with and complement other European
  and US projects
• To develop a sustainable computing model
  applicable to other sciences and industry
  biology, earth observation etc.
• Specific project objectives
• Middleware for fabric Grid management
  evaluation, test, and integration of existing M/W
  S/W and research and development of new S/W as
  appropriate
• Large scale testbed
• Production quality demonstrations
• Open source and technology transfer
• See http//www.eu-datagrid.org

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Main Partners

• CERN
• CNRS - France
• ESA/ESRIN - Italy
• INFN - Italy
• NIKHEF The Netherlands
• PPARC - UK

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Associated Partners

• Research and Academic Institutes
• CESNET (Czech Republic)
• Commissariat à l'énergie atomique (CEA) France
• Computer and Automation Research Institute, 
  Hungarian Academy of Sciences (MTA SZTAKI)
• Consiglio Nazionale delle Ricerche (Italy)
• Helsinki Institute of Physics Finland
• Institut de Fisica d'Altes Energies (IFAE) -
  Spain
• Istituto Trentino di Cultura (IRST) Italy
• Konrad-Zuse-Zentrum für Informationstechnik
  Berlin - Germany
• Royal Netherlands Meteorological Institute (KNMI)
• Ruprecht-Karls-Universität Heidelberg - Germany
• Stichting Academisch Rekencentrum Amsterdam
  (SARA) Netherlands
• Swedish Natural Science Research Council (NFR) -
  Sweden

• Industry Partners
• Datamat (Italy)
• IBM (UK)
• Compagnie des Signaux (France)

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• The Middleware Working Group coordinates the
  development of the software modules leveraging,
  existing and long tested open standard solutions.
  Five parallel development teams implement the
  software job scheduling, data management, grid
  monitoring, fabric management and mass storage
  management.
• The Infrastructure Working Group is focused on
  the integration of middleware software with
  systems and networks to provide testbeds to
  demonstrate the effectiveness of DataGrid in
  production quality operations over high
  performance networks.
• The Applications Working Group exploits the
  project developments to process large amounts of
  data produced by experiments in the fields of
  High Energy Physics (HEP), Earth Observations
  (EO) and Biology.
• The Management Working Group has in charge the
  coordination of the entire project on a
  day-to-day basis and the dissemination of the
  results among industries and research institutes.

Applications
Testbed
Middleware
Management
Infrastructure
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DataGrid Architecture
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DataGrid achievements

• Testbed 1 first release of EDG middleware
• First workload management system
• Super scheduling" component using application
  data and computing elements requirements
• File Replication Tools (GDMP), Replica Catalog,
  SQL Grid Database Service,
• Tools for farm installation and configuration
• Used for real productions
• Towards testbed 2 new functionalities and
  increased reliability

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Job submission scenario
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Other HEP Grid initiatives

• PPDG (US)
• GriPhyN (US)
• DataTag iVDGL
• Transatlantic testbeds (to address
  interoperability)
• LCG (LHC Computing Grid Project)

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The Grid World current status

• Dozens of major Grid projects in scientific
  technical computing/research education
• Considerable consensus on key concepts and
  technologies
• Open source Globus Toolkit a de facto standard
  for major protocols services
• Industrial interest emerging rapidly
• Opportunity convergence of eScience and
  eBusiness requirements technologies

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Problems

• Almost all projects have developed specialized
  services which have been layered on top of
  standard services (security, remote job
  execution, etc.)
• Patchwork of protocols and non-interoperable
  standards and difficult to re-use
  implementations
• ? Exploit Web Services

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Web Services

• Increasingly popular standards-based framework
  for accessing network applications
• W3C standardization Microsoft, IBM, Sun, others
• WSDL Web Services Description Language
• Interface Definition Language for Web services
• SOAP Simple Object Access Protocol
• XML-based RPC protocol common WSDL target
• WS-Inspection
• Conventions for locating service descriptions
• UDDI Universal Desc., Discovery, Integration
• Directory for Web services

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Open Grid Service Architecture (OGSA)

• Service orientation
• Computational resources, storage resources,
  networks, programs, databases, etc. all
  represented as services
• Allows standard interface definition mechanisms
  multiple protocol bindings, multiple
  implementations, local/remote transparency
• Grid service web service with semantic for
  service interactions
• Management of transient instances ( state)

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Global Grid Forum

• Mission
• To focus on the promotion and development of Grid
  technologies and applications via the development
  and documentation of "best practices,"
  implementation guidelines, and standards with an
  emphasis on "rough consensus and running code"
• An Open Process for Development of Standards
• A Forum for Information Exchange
• A Regular Gathering to Encourage Shared Effort
• See http//www.globalgridforum.org