14/01/ Technical Relationship between WSMX & Globus Toolkit Matthew Moran, Kashif Iqbal Digital Enterprise Research Institute, Galway {Matthew.moran, 14 Jan 2005

14/01/ Agenda Setting the scene – Introduction & motivation – Distributed computing – Framework for comparison Semantic Web Services – Rationale and research focus – WSMX Grid Computing – Rationale and research focus – Globus Toolkit WSMX and Globus Toolkit Conclusions

14/01/ Introduction Two distinct research communities – Semantic Web Services – Grid Computing – Domain of both is distributed computing systems General – do Grid and SWS fit together? – SWS on Grid – or – Grid on SWS Specific – WSMX and Globus Toolkit – What is the relationship? – Complementary or competing architectures? – If complementary, how do they fit?

14/01/ Distributed Computing Systems Motivation – The need for system and data integration across heterogeneous and autonomous systems Many previous efforts (more that are not listed) – TP Monitors – CICS, Excellent for transaction processing; tight code coupling – Client Server and RPC More flexible, still tight code coupling – Corba and DCOM Object oriented rather than business process or document integration UML a suitable modelling paradigm – Web Services Great potential but where are the semantics? BPM a suitable modelling paradigm

14/01/ Distributed Computing Systems Functional requirements – Synchronous and asynchronous message exchange – Heterogeneous and autonomous system integration – Publish and deploy services – Discover and invoke services – Data and process mediation Non functional requirements – Transparency – Availability – Maximise resource usage – Throughput – Security – Transaction processing – Reliability

14/01/ Framework for Comparison Agree on terminology – Service – Resource – Publish and deploy – Discovery – Service level agreements (SLA) – Negotiation Functional and non-func requirements Architecture Messaging Domain of interest

14/01/ Semantic Web Services What is the application area for SWS? – Application and process integration – Inter- and intra- business – Focus on business documents and processes – WS not an artificial homogeneity – SWS addresses service discovery, composition Problems with WS do they address? – Absence of formal semantics Focus for the SWS research community? – Description, discovery, composition, invocation, mediation

14/01/ WSMX Mission – To develop an execution environment for dynamic discovery, selection, mediation and invocation of Semantic Web Services – To be the middleware for Semantic Web Services Conceptual model provided by WSMO – Ontology, Goal, Service, Mediator – Describe concepts from perspectives of both the requester and provider Multiple execution semantics possible – For example, discovery or mediation only.

14/01/ WSM* Family WSMO: Conceptual Model WSML: Language WSMX: Architecture & Ref. Implementation Semantic Web Services

14/01/ WSM* Family WSMO: Conceptual Model WSML: Language WSMX: Architecture & Ref. Implementation Semantic Web Services Ontology Syntax & semantics Composition Event-based Framework Discovery InvocationMediation

14/01/ WSMX Available functionality – Backend adaptors – Accept and parse WSML messages – Store services, goals, mediators, ontologies – Simple discovery – Data mediation – Simple invocation Functionality in development – Choreography component – WSMO Editor

14/01/ Grid Overview What is the application area for Grid? – Traditionally: computational grids – Potential: for business processes and SOA – IBM dream of computing on demand WS and Grid – Globus toolkit takes advantage of widely accepted WS standards to implements its services – WS Addressing to make stateful services Research community focus for Grid? – Resource management, security, high throughput, managed availability amongst others

14/01/ What is a Grid? Evolving definition … ’98: hardware and software infrastructure that provides dependable, consistent and pervasive access to high-end computational capabilities ’00: coordinated resource sharing and problem solving in dynamic, multi-institutional organizations ’02 checklist. A grid: – Coordinates resources that are not subject to centralized control, … – … using standard, open, general-purpose protocols and interfaces, … – … to deliver non-trivial qualities of service.

14/01/ What Kinds of Applications? Computation intensive – Interactive simulation (climate modeling) – Very large-scale simulation and analysis (galaxy formation, gravity waves, battlefield simulation) – Engineering (parameter studies, linked component models) Data intensive – Experimental data analysis (high-energy physics) – Image and sensor analysis (astronomy, climate study, etc.) Distributed collaboration – Online instrumentation (microscopes, x-ray devices, etc.) – Remote visualization (biology) – Engineering (large-scale structural testing, chemical engineering) Business grids

14/01/ What Types of Problems? Security: – Hard to keep track of authentication data across institutions Monitoring/discovery: – Hard to monitor system and app. status across institutions Accessing computing/processing power – Too many ways to submit jobs Moving data – Too many ways to store & access files and data Managing data – Too many ways to keep track of data Managing systems System packaging/distribution

16 The Globus Toolkit Status and Plans, Bill Allcock, Argonne Lab Grid Conceptual Model Web Services Messaging, Security, Etc. Open Grid Services Infrastructure Domain-Specific Services Core Services Program Execution Data Services Standardization Infrastructure Services (WSRF & OGSI) Open Grid Services Architecture

14/01/ Grid and Web Services Convergence The definition of WSRF means that the Grid and Web services communities can move forward on a common base.

14/01/ What Is the Globus Toolkit? A Grid development environment – Develop new OGSA-compliant Web Services – Develop applications using Java or C/C++ Grid APIs – Secure applications using basic security mechanisms A set of basic Grid services – Job submission/management – File transfer (individual, queued) – Database access – Data management (replication, metadata) – Monitoring/Indexing system information Tools and Examples The prerequisites for many Grid community tools

14/01/ Globus Toolkit and Web Services Web services have major advantages for Grids – Standard interface definition – Good commercial tooling (eventually) However, not a silver bullet or complete solution … Globus Alliance working to advance specs … – OGSI/WSRF, OGSA-DAI, WS-Agreement, etc. – WSDL 2.0, WSDM, WS-Security, etc. … and implementation – Implementations of low-level specifications – WS-based interface to existing services – New WS-based services

14/01/ Components in Globus Toolkit 3.2 GSI WS-Security CAS (OGSI) SimpleCA Data Management Security WS Core Resource Management Information Services RFT (OGSI) RLS OGSI-DAI WU GridFTP XIO JAVA WS Core (OGSI) OGSI C Bindings MDS2 WS-Index (OGSI) Pre-WS GRAM WS GRAM (OGSI) OGSI Python Bindings (contributed) pyGlobus (contributed)

14/01/ Deployment View

14/01/ Theory -> Practice

14/01/ GT3 Security Infrastructure (GSI) OGSI/WSRF MJFS

14/01/ Network R R R A Service Level Bringing it All Together Scenario: Resource management & scheduling Storage R R R Blades R R R Notification Grid Scheduler WS-Resource used to “model” physical processor resources WS-Resource Properties “project” processor status (like utilization) Local processor manager is “front-ended” with A Web service interface Other kinds of resources are also “modeled” as WS-Resources J J J WS-Notification can be used to “inform” the scheduler when processor utilization changes Grid “Jobs” and “tasks” are also modeled using WS-Resources and Resource Properties Grid Scheduler is a Web Service Service Level Agreement is modeled as a WS-Resource Lifetime of SLA Resource tied to the duration of the agreement

14/01/ WSMX and Globus – Common Both distributed computing systems Both use WS standards as foundation technology – WSDL – SOAP Both provide approaches to B2B integration Despite current differences in focus, both face the same kind of problems – Semantics – service discovery – Service availability management – Security – Service Level Agreements (SLA)

14/01/ WSMX and Globus – Differences Different research communities Different functionalities offered right now WSMX provides SOA event driven framework Globus is a loose toolkit WSMX addresses service description, discovery, invocation and mediation at data and process Globus provides resource life-cycle mgt, soft-state, real-time service information, service notification interface, security including delegated security, access to system data and files

14/01/ WSM* Family WSMO: Conceptual Model WSML: Language WSMX: Architecture & Ref. Implementation Semantic Web Services

14/01/ WSM* Family WSMO: Conceptual Model WSML: Language WSMX: Architecture & Ref. Implementation Semantic Web Services Ontology Syntax & semantics Composition Event-based Framework Discovery InvocationMediation

14/01/ WSM* and Globus WSMO: Conceptual Model WSML: Language WSMX: Architecture & Ref. Implementation Semantic Web Services Globus Ontologies Syntax Composition Event-based Framework Discovery InvocationMediation

14/01/ WSM* and Globus WSMO: Conceptual Model WSML: Language WSMX: Architecture & Ref. Implementation Semantic Web Services Globus Ontologies Syntax Monitoring Soft-state mgt WSRF WS-Addressing Composition Event-based Framework Discovery InvocationMediation Resource Mgt Security Service Factory SLA Mgt

14/01/ WSMX and Globus – Do the fit? Complementary or competitive – complementary WSMX in Globus – or – Globus in WSMX – Neither – they address different functionalities – GT3 is implemented as a set of WS – For GT3 services to be available to WSMX, they need to be described in terms of WSMO – A GT3 client could choose to use WSMX as its discovery and execution engine while using the GT3 core services for resource mgt, security etc.

14/01/ Convergence of Grid and Web Services Grid Web WSRF Started far apart in apps & tech OG SI GT2 GT1 HTTP WSDL, WS-* WSDL 2, WSDM Have been converging The definition of WSRF means that Grid and Web communities can move forward on a common base Support from major WS vendors, especially in management space: e.g. HP, IBM

14/01/ Scenarios Stock exchange statistics example Scenario 1 – WSMX only for discovery Scenario 2 – WSMX for discovery choreography and invocation

14/01/ Conclusion WSMX is an execution environment for SWS has a particular focus – Description, discovery, mediation, invocation, etc. Globus is a toolkit providing various services that have immediate relevance for computational grids but growing relevance for business process integration Both technologies are based on WS standards  facilitates interoperability Little overlap between service offered