Ferenc Vajda*Open Grid Services ArchitectureFerenc Vajdavajda@sztaki.huComputer and Automation Research InstituteHungarian Academy of Sciences

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Ferenc Vajda*GRIDPast: GlobusPresent: OGSAFuture: Semantic GridPast is history, future is mystery

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Ferenc Vajda*Roots of OGSAGlobus Toolkit: GTPL (Globus Toolkit Public License)GT3: Platform Globus (Commercially supported)The Anatomy of the GridThe Physiology of the Grid papers by Ian Foster et al.Grid Forum GGF (Global Grid Forum)OGSA Working Group

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Ferenc Vajda*Main issues of The Anatomy of the GridSDK (Software Development Kit)

Virtual Organization (VO) Nature of Grid ArchitectureInteroperability-ProtocolServicesAPI (Application Programming Interface)

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Ferenc Vajda*-Applications Main issues of The Anatomy of the Grid 2. Architecture Description-Fabric: interfaces to local control-Connectivity: communicating easily and securely-Resource: sharing single resources-Collective: coordinating multiple resources

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Ferenc Vajda*The layered Grid architectureThe Anatomy of the Grid

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Ferenc VajdaMain issues of The Physiology of the Grid-Business-to-Business (B2B) Computing-Web Services SOAP WSDL UDDI WSFL WS-Inspection

Grid technologies-Enterprise Computing-Service Providers (SPs) Background-Globus Toolkit

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Ferenc Vajda*Building an Open Grid

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Ferenc Vajda*OpenStandardsBuilding an Open Grid

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Ferenc Vajda*OpenStandardsOpenSourceBuilding an Open Grid

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Ferenc Vajda*OpenStandardsOpenSourceOpenInfrastructureBuilding an Open Grid

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Ferenc Vajda*OpenStandardsOpenSourceOpenInfrastructureOpenGridCredit to Ian FosterBuilding an Open Grid

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Ferenc Vajda*Increased functionality,standardizationTimeCustomsolutionsApp-specificServicesGrid and Open StandardsCredit to Ian Foster

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Ferenc Vajda*Open Grid Services Architecture-Language interoperabilityFrom Web ServicesStandard interface definition mechanisms-Interface and implementation(multiple protocol bindings)

-Local/remote transparency-Service semantics

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Ferenc Vajda*Open Grid Services Architecture 2. Further services: resource management, authorization, etc.From Grids Lifecycle management Reliability and security models Discovery

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Ferenc Vajda*Open Grid Services Architecture 3. Objective: to integrate services across- distributed- heterogeneous- dynamic virtual organizations Solution:-standard mechanisms for creation, naming, discovery-location transparency, multiple protocol binding -integration with hosting environment

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Ferenc Vajda*OGSIGWD-R (draft-ggf-ogsa-platform-3) Editors:Open Grid Services Architecture Platform I. Foster, Argonne & U.Chicagohttp://www.ggf.org/ogsa-wg D. Gannon, Indiana U.OGSA Platform

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Ferenc Vajda*Principal elements of OGSA Platform Open Grid Services Infrastructure (OGSI) OGSA Platform Interfaces OGSA Platform Models

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Ferenc Vajda*OGSA Platform Profiles Sets of domain-specific servicesEnvironment, domain-specific supplements: Protocol bindings Hosting environment bindings

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Ferenc Vajda*Open Grid Services InfrastructureService groupKey Features: Grid Service description and instances Service state, metadata and introspection Naming and name resolution Fault model Lifecycle

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Ferenc Vajda*OGSIOGSI = Grid Technologies + Web Services In OGSI everything is represented as a Grid service.Service: a network-enabled entity that provides some capabilities through the exchange of messages.

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Ferenc Vajda*OGSIMost important components:Grid Service Factory Registry HandleMap

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Ferenc Vajda*The Grid Service-Grid service instance A WSDL-defined service that conforms to a set of conventions relating to its interface and behaviors.Description composed of two parts:-Grid service description-Describes a clients interaction with service instances:syntax and semantics (PortType)-Can be used by any number of Grid service instances

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Ferenc Vajda*The Grid Service 2. -Has one or more Grid Service References (GSRs)-Grid service instance-Embodies a state-Has one or more unique Grid ServiceHandles (GSHs)

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Ferenc Vajda*The Grid Service 3.GSR (Grid Service Reference): abstraction for e.g. protocol binding, network address, etc.typed (characterized by the offered capability)interfaces (set of operations) invocation (by sequences of message exchange)created/destroyed (dynamically)GSH (Grid Service Handle): globally unique name

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Ferenc Vajda*Factories: Creating Transient ServicesFactory = Factory interface + implemented serviceCreateService operation: -creates a requested Grid service -returns a GSH + an initial GSR

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Ferenc Vajda* Handles and References -returns a valid GSR GSH: reference for service instance forever GSR: changes during lifetimeHandleMap: handle-to-reference mapper-takes a GSH

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Ferenc Vajda*Registry and NotificationSemantics: protocol binding property e.g. SOAP/HTTP protocolRegistry: registry interface + service data elements(info about GSH)NotificationSubscribe operationNotificationSource interfaceNotificationSink: message (keep alive)push model (FindServiceData pull model)

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Ferenc Vajda*Client runtime architectureCredit to S. Tuecke et al. (Grid Service Specification)

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Ferenc Vajda*GSH ResolvingCredit to S. Tuecke et al. (Grid Service Specification)

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Ferenc Vajda*Open Grid Service InfrastructureImplementationHosting environment/runtime(C, J2EE, .NET, )DataaccessLifetime management Explicit destruction Soft-state lifetimeCredit to Ian Foster

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Ferenc Vajda*1a. Request to Registry for sources of data about x1b. Registry responds with Factory handle2a. Request to Factory for access to database2b. Factory creates GridDataService to manage access2c. Factory returns handle of GDS to client3a. Client queries GDS with XPath, SQL, etc3b. GDS interacts with database3c. Results of query returned to client as XMLOGSA-DAI (Data Access and Integration

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Ferenc Vajda*Security Challenges IntegrateExtensible architectureUsing existing servicesImplementation agnosticInteroperateSecure interoperabilityPublishing QoSFederationTrustTrust relationshipTrust establishmentPresumed trustAssertions

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Ferenc Vajda*Grid Security Requirements Integrity Authentication Delegation Single sign-on Credential lifespan and renewal Authorization Privacy Confidentiality

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Ferenc Vajda* Securing infrastructureGrid Security Requirements 2. Policy exchange Secure logging Assurance Manageability Firewall traversal

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Ferenc Vajda*Components of Grid Security Model

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Ferenc Vajda*Security Architecture Building Blocks

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Ferenc Vajda*Security as Service Privacy service Authentication service Identity mapping service Authorization service I/O policy service Credential conversion service Audit service Profile service

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Ferenc Vajda*Semantic GridFerenc Vajdavajda@sztaki.huComputer and Automation Research InstituteHungarian Academy of Sciences

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Ferenc Vajda*Data/Information/KnowledgeData: observed factsInformation: organized and related facts with attributed propertiesKnowledge: sum of what is known: concepts, objects with characteristics, principles, laws, know-how, etc.Semantics: a term used for meaning, interpretation, knowledge through reasoning

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Ferenc Vajda*Different Evaluations of the Grid1. Grid generations To link supercomputer centers(e.g. I-way) Toolkit- and middleware-based(e.g. Globus) Service-oriented (OGSA)

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Ferenc Vajda*Different Evaluations of the Grid 2.2. Based on the technologies used Protocol-based Service-based Semantic Web based3.Based on application requirements Data/computational Grid Information Grid Knowledge Grid

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Ferenc Vajda*Problems Related to Semantic Web Knowledge Evaluation Knowledge Representation Ontologies Agents

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Ferenc Vajda*Resource Description Framework (RDF)-Set of triplets: subject, property,object Metadata: structured data about data Resource identification: Universal Resource Identifier (URI) Most common type of URI: Uniform Resource Locator (URL) Qualified URI: URI + fragment identifier Concepts:-Graph model

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Ferenc Vajda*RDF 2.SubjectObjectProperty-Data types: based on XML Schema-Vocabulary: URI-based (Both nodes and arcs)

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Ferenc Vajda*RDF 3.

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Ferenc Vajda*What is an Ontology?Greek: ontos = being, logos = science world view regarding a domain shared understanding definitions, inter-relationship conceptualization

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Ferenc Vajda*What does an Ontology look like? vocabulary of terms specification of their meaning (i.e. definitions)- highly informal (natural language)- semi-informal (restricted, structured form of natural language)- semi-formal (artificial, formally defined language)- rigorously formal (formal semantics, proofs, completeness)

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Ferenc Vajda*Use of Ontologies communication (between people and organizations) system engineering (specifications, reusable components) inter-operability (between systems)

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Ferenc Vajda*Ontologies Web Ontology Language (OWL) Ontology: defines the terms used to describe and represent an area of knowledge-taxonomy: object classification + relationship among them (properties and inheritance of properties)-inference rules DAML (DARPA = Defense Advanced Project Agency Agent Markup Language)

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Ferenc Vajda*AgentsAgent: Capability to understand and integrate diverse information resources (based on domain ontologies)

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Ferenc Vajda* Agents 2.

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Ferenc Vajda*Semantic Web LayersCredit to Berners-Lee (XML2000 address)

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Ferenc Vajda*Semantic Grid

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Ferenc Vajda*Semantic GridBasis: Metadata enabled Goal: Grid + Semantic Web Ontologically principledNew e-Science infrastructure

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Ferenc Vajda*Servicese.g. -semantic database integration -semantic workflow description Base services-data/computational services (network access, resource allocation and scheduling, data shipping, etc.)-information services (queryprocessing, event notification, instrumentation management, etc.) Semantic services

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Ferenc Vajda*Services 2.-application Knowledge services-acquisition-modeling-publishing, use and maintenance-resource management

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Ferenc Vajda*Knowledge Grid ArchitectureCredit to Carole Goble et al.

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Ferenc Vajda*Roles of OntologiesCredit to Carole Goble et al.

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Ferenc Vajda*The term procedure used by one tool is translated into the term method used by the other via the ontology, whose term for the same underlying concept is process. procedureviewertranslator

Ontology

methodlibrarygive me the procedure fortranslatorhere is the METHOD forprocedure = ???procedure = processgive me the process forhere is the process forMETHOD = process??? = processRoles of Ontologies (Example)Credit to Rokhlenko Oleg

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Ferenc Vajda*Knowledge ServicesCredit to Carole Goble et al.

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Ferenc Vajda*Typical Applications Service discovery Knowledge annotation Workflow composition Data interpretation Collaborative science

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Ferenc Vajda*Grid Service DiscoverySimple discovery attribute-base name lookup type matchingSemantic discovery matchmaking based on ontology description

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Ferenc Vajda*Brokering vs. Matchmaking

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Ferenc Vajda*Grid Service Discovery FrameworkOntology based description used by service provider service requester service matchmaker service registry databaseMatchmaking process comparison: request to registry decision: based on filters information

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Ferenc Vajda*Service DescriptionWhat the service does: service profileHow it works: ServiceModelHow it is used: ServiceGroundingDescription by RDF(S): Resource Description Framework SchemaService profile description (human readable) functionalities functional attributes

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Ferenc Vajda*Service Description 2.Credit to DAML-S White Paper

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Ferenc Vajda*FilteringIndependent filtering is based on context matching syntactic matching- comparison of profiles- similarity matching- signature matching semantic matching

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Ferenc Vajda*myGrid project

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Ferenc Vajda*Role of Ontologies in myGrid

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