![Key terms[1]An architecture:Formal description of a systemDefines system purpose, functionsDefines system externally visible properties, and interfaces.[1] OGSA Glossary of Terms v1.0: http://www.gridforum.org/documents/GFD.44.pdf 7](https://image.slidesharecdn.com/soawsgrid-100519033314-phpapp01/85/Applications-of-SOA-and-Web-Services-in-Grid-Computing-7-320.jpg)
![88Resources[1] The Physiology of the Grid, Ian Foster, Carl Kesselman, Jeffrey M. Nick, Steven Tuecke, 2002[2] Towards a service-oriented Grid, Borja Sotomayor, University of Deusto, 2004[3] SOA, Web Service In Grid Computing, PhạmHùngTiến, ĐặngHoàiĐức, K2008[4] Open Grid Services Architecture, Ian Foster, University of Chicago, 2003[5] WS-Resource Framework: Globus Alliance Perspectives, Ian Foster, University of Chicago, 2003[6] OGSA, WSRF, and the Foundations of Grid, David Snelling, Fujitsu Laboratories of Europe, 2005[7] Global Globus Forum http://www.globus.org[8]IBM: http://www.ibm.com/developerworks/library/ws-resource/](https://image.slidesharecdn.com/soawsgrid-100519033314-phpapp01/85/Applications-of-SOA-and-Web-Services-in-Grid-Computing-104-320.jpg)
Applications of SOA and Web Services in Grid Computing
- 1. Applications of SOA and Web Services in Grid ComputingThanh H. Pham – Quynh Le19 May 2010
- 2. 31.900.0002
- 4. ObjectivesSOA – An overviewWS & Related TechnologiesOSGA & WSRF OverviewApplications ofSOA and WSin Grid Computing4
- 6. A Case StudyImage from Dr. Dang Tran Khanh slide6
- 7. Key terms[1]An architecture:Formal description of a systemDefines system purpose, functionsDefines system externally visible properties, and interfaces.[1] OGSA Glossary of Terms v1.0: http://www.gridforum.org/documents/GFD.44.pdf 7
- 8. Key terms (cont.)A serviceIs a software component Can be accessed via a networkProvides functionality to a requester8
- 9. Key terms (cont.)Service-oriented architecture refers to a style of building reliable distributed systems that deliver functionality as loose coupling servicesTechnically, then, the term SOA refers to the design of a system, not to its implementation9
- 10. Services CharacteristicsMay be individual useful, or can be integratedCommunicate with clients by exchanging messagesCan participate in a workflow10
- 11. Services Characteristics (cont.)May be completely self-contained, or may depend on other services, resourcesAdvertise details such as their capabilities, interfaces, policies, and supported communications protocolsHow’s about implementation details? Programing language, hosting platform…11
- 13. A Real Life Example13
- 14. Loose CouplingThis term implies that the interacting software components minimizetheir in-built knowledge of each other
- 15. They discover the information they need at the time they need it.14
- 16. State and StatelessnessClient can choose to go to any service that is capable of fulfilling its need: loose coupling
- 17. Loose coupling vs. tight coupling
- 18. Ex: A calculator service15
- 19. Stateless vs. StatefulEx: a transaction that requires several stepsThe service retains some information (“state”) about each stepThis might result in a delay16
- 20. Stateless Service DesignService must hand back state information to clientClient must hand the state information to whichever service it selects to process the next stepThe selected service must be able to accept and handle the state information17
- 21. A multi-step client/service interaction18
- 22. Web Services19
- 23. A Case Study20
- 24. Step 1: A customer chooses to pay with a Credit Card. 21
- 25. Step 2: They enter shipping info on your site22
- 26. Step 3: They enter their credit card details23
- 27. Step 4: They review their payment info24
- 28. Step 5: Their payment is processed. 25
- 29. Step 6: You get paid. (The fun part.)26
- 30. As easy as3 12Right?27
- 31. 28What is Web Service?Computer A:Language: PerlOS: Windows 2000XMLXMLComputer B:Language: JavaOS: LinuxA basic web serviceWeb Service Essential Book: A web service is any service that is available over the Internet, uses a standardized XML messaging system, and is not tied to any one operating system or programming language28
- 32. 29W3C:A software system designed to support interoperable machine-to-machine interaction over a network W3schools.com:Application componentsCommunicate using open protocolsSelf-contained and self-describingCan be used by other applications29What is Web Service? (cont.)
- 33. Key specifications used by Web servicesXML: eXtensibleMarkup LanguageSOAP: Simple Object Access Protocol WSDL : Web Services Description LanguageUDDI: Universal Description Discovery and Integration30
- 34. Key specifications used by Web servicesXML: eXtensibleMarkup LanguageSOAP: Simple Object Access Protocol WSDL : Web Services Description LanguageUDDI: Universal Description Discovery and Integration31
- 35. 32XML does not do anythingWith XML, you invent your own tagsXML just plain text<note> <to>Tove</to> <from>Jani</from><heading>Reminder</heading> <body>Don't forget me this weekend!</body></note>32About…
- 36. SOAPProtocol for messaging and remote procedure calling between distributed applicationsSOAP is for exchange information between applicationsSOAP is a format for sending messages33
- 38. 35A SOAP requestPOST /InStock HTTP/1.1Host: www.example.orgContent-Type: application/soap+xml; <?xml version="1.0"?><soap:Envelope><soap:Bodyxmlns:m="http://www.example.org/stock"> <m:GetStockPrice> <m:StockName>IBM</m:StockName> </m:GetStockPrice></soap:Body></soap:Envelope>35
- 39. 36The SOAP responseHTTP/1.1 200 OKContent-Type: application/soap+xml; <?xml version="1.0"?><soap:Envelope><soap:Bodyxmlns:m="http://www.example.org/stock"> <m:GetStockPriceResponse> <m:Price>34.5</m:Price> </m:GetStockPriceResponse></soap:Body></soap:Envelope> 36
- 40. WSDLUsed to define Web Services and describe how to access themDescribes location of the service, the function calls37
- 41. UDDI38
- 42. SOA and Web Services: Style vs. Implementation39
- 43. SOA Is Not Web ServicesService-orientation is an architectural styleWeb services are an implementation technology The two can be used together, and they frequently are, but they are not mutually dependent.40
- 44. Demonstration41
- 45. Open Grid Service Architecture (OGSA)
- 46. AbstractThe Open Grid Services Architecture (OGSA), set to become the standard architecture for most grid applications, depends on Web Services as the underlying middleware. OGSA first spawned the Open Grid Services Infrastructure which, despite improving Web Services in several ways, failed to converge with existing Web Services standards. The Web Services Resource Framework (WSRF), introduced last January, improves on OGSI and will eventually replace it. The presentation will cover the evolution and current state of OGSA, OGSI, WSRF, and the next version of the Globus Toolkit (GT4), which will be the first implementation of the WSRF specification.
- 48. 45Grids and Open StandardsOGSAWeb servicesGGF: OGSI, …(+ OASIS, W3C)Multiple implementations,including Globus ToolkitX.509,LDAP,FTP, …Globus ToolkitDefacto standardsGGF: GridFTP, GSIApp-specificServicesIncreased functionality,standardizationCustomsolutionsTime
- 49. 46OGSA Overview (1/2)OGSA = Open Grid Services ArchitectureOpen: communicated extensibility, vendor neutrality.
- 50. Services: OGSA is based on SOA manifested in WS
- 51. Architecture: well-defined set of basic interfaces…
- 52. Grid Services = Grid + WS; service semanticsaims to standardize the different services that are commonly found in a Grid applicationJob management, security, VO management, data management, workflow, deployment, etc.47OGSA Overview (2/2)Addressing the challenges of integrating services across distributed, heterogeneous, dynamic VO formed from the disparate resourcesOGSA was introduced in “Physiology of the Grid” (I.Foster, C.Kesselman, J.Nick, y S.Tuecke)The actual standardization process is being carried out by the Global Grid Forum (GGF) http://www.ggf.org/
- 53. 48OGSA EvolutioninformationalAutonomy ofthe GridOGSA V1.0OGSAProfileNormativeOGSA GlossaryBasic ExecutionServiceNamingJSDLPhysiology ofthe GridOpen GridServicesInfrastructureWeb ServicesResourceFrameworkWeb ServicesNotification
- 54. 49What does OGSA define?“A set of core interfaces and behaviours that address key concerns in Grid systems.”Each particular service can be accessed in the same fashion, regardless of vendor, organization, internal implementation, etc.What underlies this?How are the interfaces defined? How does a client request a particular operation from a service?OGSA relies on (&aims to improve) WS technologiesBroader context: Service-Oriented Architectures (SOA)WS & GS
- 55. 50Web Services (1)A simple but powerful distributed system paradigm, that allows one to:Describe a service (WSDL)Invoke a service (SOAP)Discover a service (various)What sets it apart?Clean separation between interface (what the service does) and implementation (how it does it)Based on standard interoperable languages (XML)Widespread use and abundant software availableWe can use web services to build SOAs, improving interoperability and reusability.
- 56. Web Services (2)Why are WS ideal for OGSA and for Grid systems?Can easily cope with heterogeneous systems (different programming languages, platforms, etc.)Common interface language (WSDL) allows:Virtualization: from a pool of services (with the same interface) I can access any service in the same fashion regardless of vendor, platform, etc.Dynamic service indexing and discovery.Dynamic access to services51
- 57. Grid Services (1)Despite being the best option for OGSA, WSs still have important disadvantages:Stateless (…)Non-transient ('Persistent')No supporting services (notifications, lifecycle management, etc.)OGSA defines the concept of a Grid Service to overcome these limitations:Grid Service = improved Web ServiceGrid Services are compatible with WSNote that Grids need access to stateful resource52
- 58. Grid Services (2)Grid servicescan maintain internal state for the lifetime of the servicecan be created and destroyed dynamically (via a Factory)have a globally unique name, the Grid service handle (GSH)each instance has a set of service data elements (a collection of XML elements)OGSA is based on Grid ServicesGrid Services are specified in a separate spec spawned by OGSA: Open Grid Services Infrastructure (OGSI).All the services in OGSA (Job management, security, etc.) will be based on (and implemented with) Grid Services53
- 60. 55OGSA Model: At a GlanceOther services – data services etcOGSA – Grid Enabled Web ServicesWeb servicesGT3 Security GT3 capabilities – e.g. GRMS, GridFTP, GRAM..
- 61. 56The OGSA PlatformMore specialized &domain-specificservicesDomain-specificprofilesOthermodelsOGSAPlatformOGSA Platform services: registry,authorization, monitoring, dataaccess, etc., etc. Models for resources & other entitiesOGSIEnvironment-specificprofilesHost. Env. & Protocol BindingsTransportHosting EnvironmentProtocolHosting Environment
- 62. 57OGSI (1)A Grid ServiceGWSDLExtends ..Web Services Web Service Interface (WSDL)SOAPServerService Implementation
- 63. 58OGSI (2)ClientIntrospection: What port types?
- 64. What policy?
- 65. What state?DataaccessGridService(required)Other standard interfaces:factory,notification,collectionsGrid ServiceHandleServicedataelementServicedataelementServicedataelementhandleresolutionGrid ServiceReferenceImplementationHosting environment/runtime(“C”, J2EE, .NET, …)
- 66. 59
- 67. 60
- 68. Globus Toolkit 3 (1)The Globus Toolkit is probably the best-known software package for Grid programmingHowever, there seems to be an ongoing confusion regarding the relationship between GT3 and OGSA + OGSI...GT3 == OGSA?GT3 == OGSI?Is GT3 a magical toolkit which will allow me to program Grid systems out-of-the-box?61
- 69. Globus Toolkit 3 (2)The Globus Toolkit 3 (GT3) is a complete implementation, in Java, of the OGSI specVery important: GT3 isn't only an OGSI implementation.Includes OGSA-defined servicesIncludes its own non-OGSA services (which have become a de facto standard)Also includes non-WS components (GT2.4)62
- 70. GT3 Architecture63Non-GT3 services based on the GT3 architectureManagement of large volumes of data (Replica Management)MMJFS, MDS, RFTGSI (Grid Security Infrastructure), SSL, WS-Security, SOAP, ...OGSI: Grid Services, Service Data, Notifications, Transient Services (Factory/Instance), Service Groups
- 71. OGSA, OGSI, and GT3(1)64
- 72. OGSA, OGSI, and GT3 (2)65In standardization process (GGF)VO management
- 73. Security
- 74. Job management
- 75. Data management
- 76. Workflow
- 77. etc.Standardized (GGF) and implemented (GT3)Standardized (W3C) and implemented (Apache Axis)
- 78. OGSA: summing upOGSA: standards-based Grid technologyFrom Web services: standard IDL, discovery, binding independence, other desirable featuresFrom Grid: naming, state, lifetime management, etc., etc.66
- 79. Web Services Resource Framework (WSRF)
- 80. 68Grid and WS: Convergence?GT1GT2OGSIStarted far apart in apps & techHave beenconverging ?WSDL 2, WSDMWSDL, WS-*HTTPDespite being generally accepted as a good change within the Grid community, OGSI has not caught the eye of the Web Service community.
- 81. GGF had hoped that Web Services standards and OGSI would converge, but that convergence is not happening.OGSA Review69StandardizationDomain-SpecificServicesProgramExecutionData ServicesCore ServicesOpen Grid Services InfrastructureWeb Services Messaging, Security, Etc.
- 82. 70Three Major WS Concerns about OGSI“Dense specification”“Does not work well with existing WS tooling”Extended WSDL & therefore not compatible with other Web service standards ..Grid services need to be stateful and dynamicTherefore, WSDL had to be extended (how) to add state & notificationToo “object oriented”Web Services are not supposed to be object-oriented, despite the fact that most Web Services are implemented using object-oriented languages. This specially refers to the fact that OGSI Services are stateful (Web Services are supposed to be stateless)Grid services extended Web services – means that Grid services are ON THEIR OWN…
- 83. WSRF (1)To achieve Web Service & Grid Service convergence, a new standard was announced during GlobusWORLD 2004 (January 2004)This new standard will supersede OGSIWSRF – Web Services Resource FrameworkOASIS, from 200671
- 84. WSRF (2)72The definition of WSRF means that Grid and Web communities can move forward on a common base
- 85. WSRF (3)73OGSA Services can be defined and implemented asWeb services instead of working w/ a diff “improved version” of WS
- 86. OSGA can take advantage of other Web services standards
- 87. OGSA can be implemented using standard Web services development tools
- 88. Grid applications will NOT require special Web services infrastructure
- 89. WSRF would be part of the WS standard, instead of being a “patch” over existing one (like OGSI)
- 90. WSRF (4)74StandardizationDomain-Specific ServicesProgramExecutionData ServicesCore ServicesOpen Grid Services InfrastructureWS-Resource FrameworkWeb Services Messaging, Security, Etc.
- 91. WSRF (5)WS-Resource: Web Service + stateful resourcePut state in the resource, not WS, each has a unique keyinstruct the WS to use a particular resource, if we want a stateful interaction with a WSPairing a WS with a resource is called a WS-ResourceWS-Resource is a construct used to model stateful resources using WS architectural frameworkUnique (for the Web Service) - Has a distinguishable identity and lifetimeStateful - Maintains a specific state that can be materialized using XMLMay be accessed through one or more Web Services75
- 92. Example of statefulWeb services76
- 93. Example of stateful Web services77Note:There are three resources, and the service interface is instructed to use Resource C
- 94. 78
- 95. 79
- 96. WSRF specificationWSRF is a collection of four different specifications related to the management of WS-ResourceWS-ResourceProperties– Supplies a set of interfaces that will allow us to access, modify, and query resource propertiesWS-ResourceLifetime: Resources have non-trivial life cycles. In other words, they are not static entity that is created when our server stops. Resources can be created and destroyed at anytime. The WS-ResourceLifetime supplies some basic mechanisms to manage lifecycle of resources.80
- 97. WSRF specification (2)WSRF is a collection of four different specifications related to the management of WS-ResourceWS-ServiceGroup – This is useful in managing groups of WS or group of WS-Resources and performing operations such as “add new service to group”, “remove this service from group”, and (more importantly), “find a service in the group that meets the condition FOOBAR”, very basic but is the base of more powerful discovery services (such as GT4’s Index Service)WS-BaseFaults– Aims to provide a standard way of representing faults when something goes wrong during WS service invocation81
- 98. Related SpecificationsWS-Notification – This is another collection of specification that, although not part of a WSRF, is closely related to it.WS-Addressing: Provides mechanism for addressing WS. More versatile than URI. Can be used to address WS-Resource pair82
- 99. 83Concerns AddressedHow WSRF deals with OGSI's problems:* “Dense specification”WSRF is divided in five documents plus a complementary specification (WS-Notification) * “Doesn’t work well w/ existing WS tooling” WSRF harmonizes with WS: less aggressive use of XML Schema, use of pure WSDL 1.1 for interface description (instead of GWSDL, a 'patched' version of WSDL fit for OGSI) * “Too object oriented”WSRF makes an explicit distinction between the “service” and the stateful “resources” acted upon by that service
- 100. Relation from WSRF to ...84OGSA: WSRF mechanisms will enable OGSAOGSI: WSRF restates OGSI concepts in WS terms
- 101. WSRF and GT485
- 102. WSRF – summing upWhy is WSRF important?WSRF completes Grid/Web convergenceHow does WSRF relate to OGSI?WSRF restates OGSI concepts in WS terms How does WSRF relate to OGSA?WSRF mechanisms will enable OGSAWhy is WSRF more likely to succeed? Harmonizes with Web ServicesBacked by IBM and HPFirst, full, free implementation: GT4IBM will include support for WSRF in some of its tools.More WSRF details: http://www.globus.org/wsrf86
- 103. Summary “Grid Computing” is undergoing an intense standardization process.OGSA: Still work-in-progress (some parts finished)OGSI: Promising start, but didn't quite make itWSRF: Will it achieve true Grid/Web convergence? Until OGSA is truly stable, the Globus Toolkit remains the de facto standard, and one of the most important pieces of software in Grid system development. 87
- 104. 88Resources[1] The Physiology of the Grid, Ian Foster, Carl Kesselman, Jeffrey M. Nick, Steven Tuecke, 2002[2] Towards a service-oriented Grid, Borja Sotomayor, University of Deusto, 2004[3] SOA, Web Service In Grid Computing, PhạmHùngTiến, ĐặngHoàiĐức, K2008[4] Open Grid Services Architecture, Ian Foster, University of Chicago, 2003[5] WS-Resource Framework: Globus Alliance Perspectives, Ian Foster, University of Chicago, 2003[6] OGSA, WSRF, and the Foundations of Grid, David Snelling, Fujitsu Laboratories of Europe, 2005[7] Global Globus Forum http://www.globus.org[8]IBM: http://www.ibm.com/developerworks/library/ws-resource/
- 105. Q & ALê H.N. Quỳnhlhnquynh@gmail.comPhạmHồngThanhthanhphh@gmail.com89
- 106. Thank You!90
- 107. 91Appendix
- 108. WSRF 101: Stateful ResourceA Resource:A specific set of state data expressible as an XML documentThis is not typically all of the resource’s state!Has a well-defined identity and lifecycle Known to, and acted upon, by one or more Web services.Many Possible InstancesFiles, Database tables, EJB Entities, XML documents, Compositions of multiple data sources, Virtualized executions of applications, etc.A WS-Resource has:Identity: Can be uniquely identified/referencedLifetime: Often created & destroyed by clientsState: Part of the state can be projected as XMLType: Its Web service interface92
- 109. LifetimeDefines:Immediate, synchronous destruction operationTime-based, scheduled destruction operation“Soft-state” or “leased” lifetime managementTermination time not required to increase monotonically Resource properties:CurrentTime: Can be used to determine clock skewTerminationTime: Current scheduled termination timeNotification of resource terminationWhy:Define clear means by which resources can be destroyedAllow the Grid to “Garbage Collect” itself automatically93
- 110. NotificationWS-NotificationBrings publish and subscribe messaging to Web servicesLoosely coupled, asynchronous messaging in WSsWS Notification composes with WSRF and other WSsBrokered notificationSupport for intermediates, queuing, aggregation, distribution, filtering, ...Topics and Topic SpacesDefine a mechanism to advertise topics for subscription.Use of WS-Notification in WS-RFReceive notification changes to the Resource Properties94
- 111. WSDL: Web Services Description LanguageBind an Interface via a definition to a specific transport (e.g. HTTP) and messaging (e.g. SOAP) protocolThe network location where the service is implemented , e.g. http://localhost:8080Define expected messages for a service, and their (input or output parameters)An interface groups together a number of messages (operations)
- 112. Web Services Server ApplicationsContainerWeb service – software that exposes a set of operationsSOAP Engine – handle SOAP requests and responses (Apache Axis)Application Server – provides “living space” for applications that must be accessed by different clients (Tomcat)HTTP server- also called a Web server, handles http messages Borja Sotomayor , http://gdp.globus.org/gt4-tutorial/multiplehtml/ch01s02.html
- 113. Let’s talk about statePlain Web services are stateless Borja Sotomayor , http://gdp.globus.org/gt4-tutorial/multiplehtml/ch01s03.html
- 114. However, Many GridApplications Require State Borja Sotomayor , http://gdp.globus.org/gt4-tutorial/multiplehtml/ch01s03.html
- 115. Keep the Web Serviceand the State SeparateInstead of putting state in a Web service, we keep it in a resource Each resource has a unique key Borja Sotomayor , http://gdp.globus.org/gt4-tutorial/multiplehtml/ch01s03.html
- 116. Web Service+ Resource=WS-ResourceAddress of a WS-resource is called an end-point reference Resources Can Be Anything Stored
- 117. “Stateless” vs. “Stateful” ServicesWithout state, how does client:Determine what happened (success/failure)?Find out how many files completed?Receive updates when interesting events arise?Terminate a request?Few useful services are truly “stateless”, but WS interfaces alone do not provide built-in support for stateFileTransferServiceClientmove (A to B)move
- 118. GT3/GT4 Evolution102
- 119. Grid services vs. Web ServicesAlthough Grid services are implemented using WS technology, the following are the differences btw themWeb serviceAddresses the issue of discovery and invocation of persistent services
- 120. A WS is often presumed available if its corresponding WSDL file is accessible to its client
- 121. WS typically outlive all their clientsGrid serviceAddresses the issue of a virtual resource and its state management
- 122. A grid is a dynamic environment hence, Grid services can be transient rather than persistent
- 123. A Grid service can be dynamically created and destroyed.104SYSTEMSMANAGEMENTUTILITYCOMPUTINGGRIDCOMPUTINGUse Cases &ApplicationsDistributed query processingData CentreASPCollaborationMulti MediaPersistent ArchiveVO ManagementOGSA-EMSOGSA Self MgmtWS-DAIWSDMDiscoveryInformationNamingGGF-URData ModelCore ServicesPrivacyOthers ...TrustNotificationService GroupsWS-I BPWSRF-RAPWS-SecuritySAML/XACMLX.509Basic ProfileWS-AddressingHTTP(S)/SOAPWSDLWSRF-RLWSRF-RPOGSA Specs Landscape
Editor's Notes
- #2: thanh.phamhong@niit.edu.vnYahoo ID: thanhphh
- #3: Thoigian: 30sSlidekhoidau, gioithieu mot so y ve SOA, nhanmanh y SOA duoccaccongtycongnghelonquan tam
- #4: Thoigian: 30sPhan 1: 15 phutPhan 2: 15 phutDemo 1: 15 phutPhan 3 + Demo: 45 phut
- #5: Thoigian: 30sWhat will the audience be able to do after this training is complete? Briefly describe each objective how the audiencewill benefit from this presentation.
- #6: Thoigian: 15phut
- #17: Explain the example
- #20: Thoigian: 15phut
- #40: Thoigian: 15phut
- #43: Thoigian: 15phut
- #45: What will the audience be able to do after this training is complete? Briefly describe each objective how the audience will benefit from this presentation.
- #49: Quypham
- #51: Separation of interface and implementation:- Interface is defined in an XML language called WSDL (Web Services Description Language). - WSDL is language and platform-neutral, and allows the interface to be defined separately from the particular transport protocol or data encoding used in the actual message passing. e.g. A GNU/Linux client can access a web service in a Windows server using protocol A, while a different client using Solaris might use protocol B.Stateless, but with associated resources
- #52: Without state, how does client:Determine what happened (success/failure)?Find out how many files completed?Receive updates when interesting events arise?Terminate a request?Few useful services are truly “stateless”, but WS interfaces alone do not provide built-in support for state
- #53: The Web Service itself is typically StatelesswhileGrids Need Access to Stateful Resources
- #57: Realizing a Service-Oriented Architecture: How Do I- Create, name, manage, discover services?- Render resources, data, sensors as services?- Negotiate service level agreements?- Express & negotiate policy?- Organize & manage service collections?- Establish identity, negotiate authentication?- Manage VO membership & communication?- Compose services efficiently?- Achieve interoperability?
- #64: Job Management (MMJFS), Monitoring and Discovery Services (MDS), Reliable File Transfer (RFT)
- #66: Application
- #68: Thoigian: 15phut
- #69: Hội tụ
- #71: Grid services need to be stateful and dynamicTherefore, WSDL had to be extended (how) to add state & notification
- #72: Separate service from resourceService is static and statelessResource is dynamic and statefulIn order to keep WS stateless and still capture state information, the solution is to simply keep the WS and state information completely separate.Instead of putting the state in the WS, it will be kept in a separate entity called a resource, which will store all the state information.Each resource will have a unique key Whenever we want a stateful interaction with a WS, we simply have to instruct the WS to use a particular resourcePairing a WS with a resource is called a WS-Resource
- #74: OGSA would be based directly on WS, instead of working w/ a diff “improved ver” of WSWSRF would be part of the WS standard, instead of being a “patch” over existing one (like OGSI)
- #84: WSRF explicitly separates the service (which will always be stateless) from the state (which is called resource in WSRF lingo). In a typical interaction, the client will have to specify what resource (i.e. what state information) must be used during that particular interaction.
- #85: The transition from OGSI to WSRF will be simpleDirect mapping from OGSI features to WSRF
- #87: Services are typically stateful, but WS standards did not support stateful entitiesWSRF provides standards for management, identification, lifetime, inspection, & manipulation of stateful entitiesGT4 WS Core provides a rich environment for developing stateful servicesGT4 provides a rich set of services based on WSRF & WS-Notification
- #88: Chuẩnphổbiến, kochínhthức