Some Basicsof Globus Web Services

Adarsh Patilhttp://www.adarshpatil.com/

http://www.adarshpatil.com/grid_tutorial.htm

GGF-Globus Grid Forum

GGF4 was formed on Feb 2002Globus team and IBM proposed first OGSA specification to merge Globus and Web Services (globus 2.x to globus 3.x)

This is a body for designing standards for the Grid.

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OGSI-Open Grid Service Implementation

It is an technical specification for the implementation of Grid Services as described in the OGSA specification

Globus Toolkit 3 and 4 are OGSA complaint and are Service Oriented Grid Systems

Grid services are transient and stateful. Due to heavy specifications in one and only OGSI (too many specification in OGSI) it does not fit in web services and xml protocols

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WSRF-Web Service Resource Framework

Globus Alliance + IBM + HP --> introduced WSRF to solve this issue ( many implementations in specification of OGSI)

WSRF standard promises this effort

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Web Services

Based on Service Oriented Architecture

Clients are service RequestorsServers are service ProvidersXML, http, SOAP, WSDL, UDDI, WS-Inspection language are used

Request, Publish, Registry

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WSDL-Web Service Description Language

It’s a XML based specificationIt is used to describe Web Service

It describesWhat a service can do?Where is its location?How to invoke it ?

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SOAP-Simple Object Access Protocol

It’s a communication protocol for clients and servers to exchange messages in XML format over http

It specifies rules, header, body(URI)

The message containsSOAP envelopeSOAP schemaXML schema definition

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UDDI-Universal Description, Discovery, and Integration

Service discovery and registrationUsed to advertise servicesUsed to find appropriate servicesUse to publish/obtain servicesProvider, User, Registry - white pages, yellow pages , green pages

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OGSA- Open Grid Service Architecture

Architecture to build service oriented Grid.

It is based on web servicesIt uses protocols such as xml, httpConcept of Grid Services was introduced in OGSA

It defines various aspect of Grid Service and interfaces that are needed.

OGSA-WG is the work group which works on the design of OGSA specification

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Credits/Acknowledgements

http://www.globus.orghttp://www.globusconsortium.com/ http://www.globusworld.org/http://www.ggf.org/Text BooksThe Grid 2: Blueprint for a New Computing Infrastructure (The Morgan Kaufmann Series in Computer Architecture and Design)

The Grid : Core TechnologiesGrid Computing: Making The Global Infrastructure a Reality