4a.1

Grid Computing Standards

ITCS 4010 Grid Computing, 2005, UNC-Charlotte, B. Wilkinson, slides 4a.

4a.2

Standards BodiesThe primary standards-setting body is1:

• Global Grid Forum (GGF)– Started in 1998– Meets three times a year, GGF1, GGF2, GGF3 …– More than 40 organizations involved and growing …

Others:

• W3C consortium (Worlds Wide Web Consortium)– Working on standardization of web-related technologies such as XML– See http://www.w3.org

• OASIS (Organization for the Advancement of Structured Information Standards)

• IETF, DMTF

1 “The Grid Core Technologies” by M. Li and M. Baker, 2005, page 4.

4a.3

Standards in the Web Services World

• XML introduced (ratified) in 1998• SOAP ratified in 2000• Web services developed• Subsequently, standards have been are

continuing to be developed:– WSDL– WS-* where * refers to names of one of many

standards

4a.4

Standards in the grid computing world

• Open Grid Services Architecture (OGSA)

• First announced at GGF4 in Feb 2002

• OGSA does not give details of implementation.

4a.5

Grid computing software

Started before standards became accepted.

Gone through several development cycles:

4a.6

• Originally own protocols were developed (e.g. GT2)

Then

• OGSA (Open Grid Services architecture) standard and a specification called OGSI (Open Grid Service Infrastructure) was developed. Extended web service was invented called a grid service to embody state and transience. (GGF) Implemented in GT3.

And

• Now relies more directly upon developing web service standards (GT 4)

1996-2002

2002-2004

2005 -

4a.7

Grid computing standards

• Figure from “An ‘Ecosystem’ of Grid Components”, 2004, Grid Research Integration Deployment and Support Center, http://www-unix.grids-

center.org/r6/ecosystem/ecology.php

4a.8

Open Grid Services Architecture(OGSA)

Although OGSI vanished, OGSA continues …

4a.9

OGSA

• Defines standard mechanisms for creating, naming, and discovering service instances.

• Addresses architectural issues relating to interoperable services for grid computing.

• Originally described in “The Physiology of the Grid” http://www.globus.org/research/papers/ogsa.pdf

4a.10

WS-Resource Framework

• A specification developed by OASIS, essentially to replace OGSI and make the implementation of a stateful web service acceptable.

• Specifies how to make web services stateful and other feature, without drifting from the original web services concept.

4a.11

4a.12From “The Globus Toolkit 4 Programmer’s Tutorial” by Borja Sotomayor.

4a.13From “The Globus Toolkit 4 Programmer’s Tutorial” by Borja Sotomayor.

4a.14

WS-* StandardsPrincipal web service standards adopted for grid

computing:

• WSRF Framework collection of 5 specifications:– WS-ResourceProperties

• Specifies how resource properties are defined and accessed

– WS-ResourceLifetime• Specifies mechanisms to manage resource lifetimes

– WS-ServiceGroup• Specifies how to group services or WS-Resources together

– WS-BaseFaults• Specifies how to report faults

4a.15

WS-* Standards continued

• WS-Notification– Collection of specifications that specifies how configure

services as notification producers or consumers

• WS-Addressing– Specifies how to address web services.– Provides a way to address a web service/resource pair

4a.16

GT 4 Stateful Web Services

• Web services as created in assignment 1 are stateless.

• Stateful web services required for grid computing.

• Obtained in WS-RF by having a web service front-end to a stateful “resource.”

4a.17

Web Service

Resource

Resource properties

Client

Web Service Resource Framework(WS-RF)

Holds information retained between accesses.

4a.18

Example with a “database” resource

The Grid 2: Blueprint for a new Computing Infrastructure, Ian Foster, Carl Kesselman and Steve Tuecker Editors, Morgan Kaufmann 2004 -- Chapter 17: “The Open Grid Service Architecture,” by Ian Foster, Carl Kesselman and Steve Tuecker.

4a.19

• In this example, the client accesses a file transfer service to perform actions such as transfer a file from one storage service to another.

• Because based upon web services, uses web services technology, XML, WSDL, etc.

4a.20

WSDL file with WS-RF

• Serves the same purpose as the WSDL file in web services – to define the service interface.

• A significant addition in the WSDL file is to specify the resource.

4a.21

Service Interface

• If service implements operations on WSRF resource properties, WSDL will include definitions relating to resource property.

4a.22

Service Implementation

• If service uses WS-RF mechanisms, implementation must include code for resource implementation and resource home.

4a.23

• More detail on WS-RF when we do assignment 2, which asks us to create a Globus 4 service. GT 4 uses WS-RF.

• First though, let us look at GT4.