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A brief introduction to

The Grid

seminar 8th June 2005Guillermo Losilla Anadón

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Definition

• Grid Computing, commonly named ”The Grid”, is a growing technology...

• Everybody speaks about it, but...

what really is it?

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What is the Grid?• The “short” answer:

“Grid computing is a technology whose final objetive is to connect all the heterogeneus computers around the world which share their computational power and storing resources, to build the most powerful computer in the globe: the GRID“

• User’s view: for the final user, the Grid will act as a single, huge and powerful computer.

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Who will use the Grid?

• Scientists are currently the most interested group in the development of the Grid: molecular simulation, study of the fundamentals of particles, human genome, Earth observation, climate modeling...

• ...but some companies have already began to invest in grid technologies (although they have a different vision...)

• It is expected that in the future anyone will take advantage of it; will we pay for it?

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Power grid analogy

• Infrastructure

• Transparency

• Utility

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Reality or fiction?

• The reality is that the utopic view of The Grid is still a dream... but reality is evolving increasingly fast

• The Grid is ”a work in progress”, with the underlying technology still in a prototype phase, and being developed by hundreds of researchers and software engineers around the world

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The way to the Grid

DISTRIBUTED COMPUTING

METACOMPUTING (FAFNER and I-WAY )

P2P COMPUTING

INTERNET COMPUTING (SETI@HOME)

CLUSTER COMPUTING (BEOWULF)

THE GRID

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Operation of the Grid

Ok, the Grid is a cool idea but...

How does it work?

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Grid middleware

• The Grid is posible thanks to the "grid middleware", which is the special software necesary to organize and integrate all the disparate computer facilities involved in the Grid.

• Currently most effort invested in the Grid is used to develop grid middleware

• The Grid middleware is built using grid services which in turn are based on web services (although this is not true any more...)

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Web services

• Web services technology provides a middleware for programming distributed access applications

• Some ”original” features of web services:– plattform independent: use SOAP(XML) for

communication– HTTP protocol for transmiting messages– Adequate for loosely coupled systems

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Web services: use case

taken from The Globus Toolkit 4 tutorial ®

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Grid services

• The first grid engineers who began to develop the Grid software chose web services amongst other distributed middleware(RMI, CORBA, RPC...) as a base for the Grid architecture

• However they added some features to web services in order to skip the shortcomings found in web services:

they created grid services

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Grid services vs web services

• features added to grid services:

– State– Transiency– Service data– Notifications– Lifecycle management

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Last news!Grid services = web services

• Since WSRF release (Jan 2004):

grid services = web services

• Already present in GT4 (released April 2005)

taken from The Globus Toolkit 3 tutorial ®

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The Globus Toolkit

• The Globus toolkit is an open source infrastructure developed by The Globus Alliance at the Argonne National Laboratory (Ian Foster’s team + IBM) which has become the "de facto" standard to build grid middleware.

• It provides many of the basic services needed to construct grid applications, such as security, resource discovery, resource management and data access.

• Last release: 4.0 (WSRF-compliant)

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Who designs the Grid?

• The Global Grid Forum is the main body which

dictates the grid-specific standards

• It released OGSA (Open Grid Service Architecture) the open standard that describes the features a grid service must observe

• ...take into account the ”power” of The Globus Alliance as the Globus Toolkit developer

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Useful links

• To get an overview of the Grid:– GridCafé: http://gridcafe.web.cern.ch/gridcafe/– Global Grif Forum: http://www.gridforum.org/

• To learn how to develop grid applications:– The Globus Toolkit: http://www-unix.globus.org/toolkit/– GT4 tutorial: http://gdp.globus.org/gt4-tutorial/