UK e-Science All-Hands MeetingNottingham, 2004

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Enterprise specification of theNERC DataGrid

Andrew Woolf, A.Woolf@rl.ac.uk1

Ray Cramer2, Marta Gutierrez3, Kerstin Kleese van Dam1, Siva Kondapalli2, Susan Latham3, Bryan Lawrence3, Roy

Lowry2, Kevin O’Neill1

1CCLRC e-Science Centre2British Oceanographic Data Centre

3British Amospheric Data Centre

UK e-Science All-Hands MeetingNottingham, 2004

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Principal partners:British Atmospheric Data Centre

British Oceanographic Data Centre

CCLRC e-Science Centre

Program for Climate Model Diagnosis and Intercomparison (LLNL), EarthSystemGrid

UK e-Science All-Hands MeetingNottingham, 2004

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NERC DataGrid

British Atmospheric Data Centre

British Oceanographic Data Centre

Simulations

Assimilation

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Outline:• Grid ‘identity crisis’

• RM-ODP

• NDG Enterprise specification

• Process

• Summary / conclusions

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The Grid ‘identity crisis’

The GRI D – Hype or Reality?Roger Barlow

Manchester and Stanford University

Symposium in celebration of J ohn Vincent AtanasoffI owa State University, 31st October 2003

What is the Grid?Problems and Tools that solve themProgressProspects

• Need to identify defining patterns of Grid computing

• Formal architectural methodologies may help in abstracting these patterns

• Requirements capture and analysis is starting point of any formal architecture

UK e-Science All-Hands MeetingNottingham, 2004

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Reference Model for Open Distributed Processing (RM-ODP) (1)

• ISO 10746-{1,2,3,4}• Formal architecture methodology for distributed

systems• Viewpoints approach

Enterpriseviewpoint

NDG

Informationviewpoint

Computationalviewpoint

Technologyviewpoint

Engineeringviewpoint

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Reference Model for Open Distributed Processing (RM-ODP) (2)

Enterprise viewpoint• roles, activities, policies (incl. VO)

Information viewpoint• semantics of information and information processing

(static, invariant, dynamic schema)

Computational viewpoint• interfaces and computational objects (cf. CORBA

IDL, WSDL portTypes)

Engineering viewpoint• distribution infrastructure (e.g. web services, WSRF

vs OGSI)

Technology viewpoint• choices of technology (e.g. app servers, DBMS)

UK e-Science All-Hands MeetingNottingham, 2004

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Reference Model for Open Distributed Processing (RM-ODP) (3)

Enterprise viewpoint:• Specification of purpose, scope and policies of system in

terms of:

• roles: “identifier for a behaviour”

• activities: ordered sequence of actions

• policies: set of obligations, permissions or prohibitions

• Stakeholders must agree on these!

• Structured basis for requirements capture and analysis

• UML Use Cases, Collaborations, Activity Diagrams may be useful (NB: ISO/IEC 19793 “Information technology – Open distributed processing – Use of UML for ODP system specifications” developing UML profile)

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NDG Enterprise specification

UK e-Science All-Hands MeetingNottingham, 2004

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NDG Enterprise specification: Process (1)• Original plan: one major face-to-face meeting for

each RM-ODP viewpoint• TOO OPTIMISTIC!• Finally: series of meetings on Enterprise

specification, i.e. precisely what NDG was intended to do

• Requirements refined into EV roles, activities, policies between meetings

• Conflicts, assumptions identified for followup discussion

UK e-Science All-Hands MeetingNottingham, 2004

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NDG Enterprise specification: Process (2)e.g.: Security

• clear that role-based system was required

• took considerable discussion amongst all partners to settle on details of authorisation model (see Lawrence et. al., this meeting)

e.g.: Data ‘discovery and access’• refined into explicit activities:

search detailed metadata browse data browse/selection deliver data

e.g.: User ‘Workspace’• identification of EV ‘Workspace Provider’ role raised resource-sharing

issues

UK e-Science All-Hands MeetingNottingham, 2004

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NDG Enterprise specification: Process (3)Needed involvement of:

• resource owners, users, implementers, project collaborators

Not trivial to reach agreement on VO contracts!

Engagement with experts on current systems:• complexity of real-world datasets

• legacy operational systems

• deployment practicalities, etc...

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Summary and conclusions (1)

• RM-ODP useful methodology for architecting Grids

• EV provides structured approach to requirements capture and analysis (roles, activities, policies)

• Need involvement of all stakeholders

• Structured approach helps minimise system scoping from drifting to implementation details

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Summary and conclusions (2)• RM-ODP viewpoints assist detailed design, e.g.:

• NDG EV activities divide naturally along metadata/data lines core components of Information Viewpoint

• NDG Computational Viewpoint interfaces strongly motivated by EV activities

• Formal architecture/requirements capture for abstracting Grid patterns?