Grid Computing
Its Promise and Challenges
Tom Smith
Master’s Candidate
Computer Science
Union College
January 2004
What is Grid Computing?
 The word “grid” is chosen by analogy with
the power grid:
 “always on” resource
 Users don’t need to know where the resource
is coming from
 Global (or at least national) standard
 The Grid may be as revolutionary as the
power grid and the PC were at their time
of introduction.
What is Grid computing?
 Classic example: SETI@Home
 The basic definition (for today): Grid
computing is assembling more than
machine or system into a unified resource.
 Little agreement about what exactly
constitutes a “grid”
 Refer to “progression of parallel
computing”
What is Grid computing?
 Ian Foster: Luminous figure in the field,
based at U of Chicago and Argonne
National Laboratory
 Argues for a formal definition of the grid
Foster’s Definition
 Grids are motivated by virtual
organizations
 Grids are heterogeneous in many ways:
 Diverse machine configurations
 Diverse network issues
 Diverse authentication methods
 “Real” grids embrace heterogeneity
Foster’s Definition, cont’d
 Grids should be able to talk to one another
(intergrid protocols)
 Most important: grids allow access to a variety of
resources (not just cycles)
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Sensors
Storage
Databases
Memory
Applications
Etc.
Early Success: SETI@Home
 Search for ExtraTerrestrial Intelligence
 Runs as a screensaver/background app
 35GB daily tapes split into 250kb chunks
 Almost 5 million users
 ~1500 signed up yesterday
 1,781,106.179 years of CPU time has
been contributed to date
Early Success: United Devices
 Based on intranet at Novartis (drug
research)
 Molecular modeling
 Alternative to buying a new highperformance computer
 Saved $2,000,000 with a $400,000
investment
United Devices: cont’d
 Projects that would have taken 6 years,
now take 12 hours.
 Initial test was on 2,700 corporate PCs
 So successful, installing it on all 70,000
corporate desktops
United Devices: Also available
 Grid MP Alliance: sell your corporation’s
excess cycles to UD
 Grid MP Global: “rent” cycles from UD
 Implementation of something that seemed
only theoretical short time ago
 “Computing on demand”
Challenges of Grid computing
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Security
Bandwidth/networking
Authentication/authorization
Storage
Reliability: what if a node goes down?
Reporting
Synchronization
Nearly every aspect of computer architecture
touched.
Strategies for Simplifying Problem
 Virtualization/abstraction
 Virtual OS
 Standards
Anatomy of the Grid
 Influential paper, 2001: Foster et al.
 Introduced notion of virtual organization
 Suggested “an open and extensible grid
architecture”
Physiology of the Grid
 Another influential paper
 Foster et al., June 2002
 New concepts:
 Open Grid Services Architecture (OGSA)
 Shift in focus from “resources” to “grid
services”
 Grid services are a special instance of web
services
Web Services
 Cross-platform way of letting different
systems interact and exchange
information
 Based on WSDL and SOAP
SOAP
 Simple Object Access Protocol
 Maintained by W3C, current ver. 1.2
 XML-based, runs on top of HTTP
 Simple, platform-independent way of
exchanging info between 2 endpoints
 An “envelope” protocol
 Click here for example
WSDL
 Web Services Description Language
 Developed/Supported by IBM, Microsoft
 Proposed standard to W3C, latest proposal is
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version 1.2
XML-based, works in conjunction with SOAP,
HTTP, MIME
portType: defines function library or class that is
being used/requested
Click here for example
Click here for Complete WSDL example
w/SOAP binding
OGSA and OGSI
 OGSA = Open Grid Services Architecture
 Web Services + standard grid interfaces =
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grid services
OGSI = Open Grid Services Infrastructure
OGSI v1.0 was released by Global Grid
Forum in June 2003
Click here for illustration of OGSA
Click here for illustration of OGSI
Note: Globus Toolkit
 Open-source collection of libraries and
functions for implementing grids
 “De facto standard” for grid software
 Foster involved from the beginning
 Generated much of OGSA, OGSI
Adoption of OGSA/OGSI
 Initially, confusion reigned (January 2003)
 Situation clearer after release of OGSI
(June 2003)
 Most of the grid vendors pay at least lip
service to OGSA/OGSI
 WSDL’s full incorporation of grid concepts
may make OGSA/OGSI less important
 For example: United Devices’ software
makes use of SOAP and WSDL
“The” Grid
 Akin to “The internet”
 Still just a concept
 No grids talking to each other in any
significant ways yet
 Lots of obstacles to overcome first
Case Study: GridFTP
 GridFTP was a protocol developed by
Foster et al. for Globus Toolkit 2.
 Click here for image.
Motivations for Grid Computing
 High-performance computing
 Processor cycle recovery
 Resource sharing
 Collaboration
 Approaches have been parallel so far, but
are converging.
Questions?
Question
 Gregory Andrews: “Even most personal
computers will soon have a few
processors” (2000)
 Will the grid make multiprocessor
computers irrelevant?
Question
 Will “The Grid” become as pervasive as
the internet?
Question
 What about bandwidth issues?
 How will the irregular rollout of high-speed
networks affect the expansion of the grid?
Question
 Will home PCs play any significant role in
high-performance computing?
 Will organizations without the need for
high-performance computing rent out their
resources?
 How will the grid change the nature of the
PC?
Question
 According to The New York Times, Europe
is exceeding the U.S. in their
implementation of grid technologies.
 Is this important?