1. © 2006 Open Grid Forum Workflow Management Research Group - WFM-RG OGF 22 Ian Taylor, Andrew Harrison and Ewa Deelman

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4. © 2006 Open Grid Forum 4 Boston OGF - OGF22 1:45 Session Overview (Taylor) Background on Research Document Past Efforts on interoperability 2:10 OGF Survey on interoperability (Harrison) Responses from community Conclusions 2:30 Discussion of Research Document The way forward Community involvement 3:00 Session Talks/Presentations Farrukh Nadeem - Characterizing, Modeling and Predicting resource availability in the Grid Focus - Research Document

5. © 2006 Open Grid Forum 5 Motivation for Research Document The Story so far … Focus on sharing and Interoperability Accept co-existing workflow representations/ environments How do we share/reuse workflows? Focus on the scientist performing the experiment How can sharing help him/her Workflow Interoperability Do we need this - use cases? Workflow embedding?

6. © 2006 Open Grid Forum 6 Motivation: Types of Sharing Intra domain for collaboration on the same workflow Inter domain - reuse of algorithms/services Provenance issues/living documents/logging/storage Sharing strategies for optimising/design of workflows Support full research cycles/iteration Search/discovery of services/workflows Exposing/organising research - workflows/papers/people Tagging/annotation

7. © 2006 Open Grid Forum 7 WFM-RG Past Efforts Related Meetings - background and further motivation for proposed research

8. © 2006 Open Grid Forum 8 Manchester - OGF 20 10:35 Levels of the Grid Workflow Interoperability - Adrian Toth, University of Miskolc. 10:45 "Workflow Optimization and Sharing Using Performance Information" - Omer Rana, Cardiff University 10:55 "Scheduling Data Intensive Workflows Onto Storage-Constrained Distributed Resources" - Rizos Sakellariou, University of Manchester 11:05 "myExperiment - social software for workflow sharing" - David De Roure, University of Southampton and OMII-UK 11:15 "The WHIP Plugin for Workflow and Artefact Sharing" - Andrew Harrison, Cardiff University 11:25 "Shibboleth Protection and Management of Workflows" - Richard Sinnott, National e-Science Centre, University of Glasgow 11:35 "A Workflow Mapping Mechanism for establishing Quality of Service Guarantees", Dimosthenis Kyriazis, Telecommunications Laboratory, National Technical University of Athens 11:35 Discussion on Document Focus Focus - Workflow Sharing

9. © 2006 Open Grid Forum 9 Seattle OGF - OGF21 9:00 Session Overview - Ian Taylor 9:05 Matt Shields – Sharing Workflows Recap of OGF 20 9:15 Research document use cases for workflow sharing, volunteers 9:20 Ewa Deelman NSF Workflow Interoperability workshop and what transpired in the execution breakout 9:35 Andrew Harrison Kepler/Triana integration - interoperability Use Case 1 9:50 Maurizio Melato--- Web Based Grid Workflow System: A- WARE project 10:05 Dave De RouremyExperiment 10:20 All---Future plan (Use cases documents) Focus - Workflow Interoperability

10. © 2006 Open Grid Forum 10 WORKS 07 The 1st (Paris) and 2 nd Workshop on Workflows in Support of Large-Scale Science (WORKS07) 2nd on 25th June @ HPDC (Monterey, California) Deelman and Taylor, co-chairs Areas: Workflow Systems Adaptation and Integration Workflow Applications and Models Short Papers

11. © 2006 Open Grid Forum 11 Workshop on Scientific and Scholarly Workflow Cyberinfrastructure Baltimore, Maryland, Oct 3-5, funded by the National Science Foundation The goal of our workshop was to address the issue of interoperability, sustainability and platform convergence in scientific and scholarly workflow. Bring together key parts of the developer/user/supporter communities and see if there are concrete steps that can be taken to a shared, sustainable workflow cyberinfrastructure. Much discussion, current interoperability between systems is weak

12. Lots and lots of Workflow Systems 27 Chapters - from applications and environments BPEL, Taverna, Triana, Pergasus, Kepler, P-Grade, Sedna, ICENI, Java CoG Workflow, Condor, ASKALON, Swift, Petrinets, and so on … Successfully used - choice depends on requirements and politics :)

13. © 2006 Open Grid Forum 13 WFM-RG Current State-of-the-art Related past efforts Need more contribution from eScience community on sharing On-going See survey later

14. © 2006 Open Grid Forum 14 Past Efforts by the WfMC

15. © 2006 Open Grid Forum 15 WfMC - Types of Interoperability

16. © 2006 Open Grid Forum 16 WfMC - Types of Interoperability 2

17. © 2006 Open Grid Forum 17 Existing Workflow Standards Workflow Management Coalition (WfMC) identifies five functional interfaces, that connect a workflow management system with external application systems, of which Interface 4 deals with workflow interoperability, which defines abstract protocol for peer-to-peer interaction of workflow enactment services, potentially across business domain boundaries Supports scenario where an activity in a workflow process hosted by an enactment service is realized by a subprocess hosted by another enactment service. A typical example is an interenterprise workflow, such as those found in supply-chain interactions. Provides interoperability on the workflow-process level only; internals of a process instance need not be known across business domain boundaries.

18. © 2006 Open Grid Forum 18 WfMC Interface 4 Efforts SWAP (1998) - define an Internet-based workflow access protocol to instantiate, control, and monitor workflow process instances SWAP is a binding of the jointFlow object mode Slow adoption, community if favour of XML-based comms Wf-XML - SWAP successor (1999) interoperability standard that combines the elementary concept of SWAP with the abstract commands defined by the WfMC Interface 4 Defines an interoperability contract HTTP is core transport mechanism for Wf-XML messages

19. © 2006 Open Grid Forum 19 Wf-XML WfMC defined (2000) a binding of the standard, which uses asynchronous interaction via e-mail as the transport, with MIME encoding of the information to be exchanged. Asynchronous Messaging - loosely coupled Other bindings exist

20. © 2006 Open Grid Forum 20 WfMC Other Related Work - XPDL XML Process Definition Language Describes workflows at an abstract level Use-case - a meta language that acts as a bridge between proprietary languages understood by different engines. Benefits A many-to-one mapping between engines It exists no new specs A number of implementations Drawbacks Complex spec 30 pages of XML Schema Each translation to a workflow must be hand-crafted (by someone who understands XPDL and the engine specific language).

21. © 2006 Open Grid Forum 21 WfMC - Conclusions We should build on or reuse lessons learned and previous efforts They focus on the sub-process level (embedding) for interoperability Also, defining a meta language for modelling workflows (e.g. XPDL) This is the b2b case Are current eScience scientific workflow systems too different (heterogeneous components, different models of execution and so forth)

22. © 2006 Open Grid Forum 22 Questionnaire - eScience Input Gathering Data for research Document From eScience community experience on interoperability - requirements analysis We asked the community to contribute to issues surrounding workflow interoperability and sharing Had a handful of responses You can still contribute at: http://bender.astro.cf.ac.uk/wfmrg/

23. © 2006 Open Grid Forum 23 Summary Feedback from developers and users of: GridBus Workflow Engine UNICORE Inforsense Triana Taverna Kepler BPEL

24. © 2006 Open Grid Forum 24 Interoperability Requirement for interoperability between workflow systems Comparing workflow systems with one another Embedding existing workflows that run in a different environment Using desktop interface to design in a chosen language Challenges to workflow interoperabiltiy Language used to describe Scientific Workflows Definition of workflows at an abstract level Semantics of workflow and data Security The term religious was mentioned more than once Benefits of interoperability Reuse A wider audience for workflow designers Achieving interoperability, two approaches idenitified Defining workflow schema at an abstract level Allowing workflow engines to be forked as a sub-process (embedding)

25. © 2006 Open Grid Forum 25 Sharing Requirement of sharing of workflows Reuse, modification, refining Challenges to workflow sharing Language used to describe Scientific Workflows Native engine enactment of shared workflows (embedding) Trust and security Workflow dependencies/time sensitivity Benefits of sharing Reuse Need driven approach to standardisation - sharing capability as an incentive to achieving interoperability Understanding what can be shared Faster discovery Achieving sharing Standards for semantics/description Community portal

26. © 2006 Open Grid Forum 26 Conclusions Projects do have a need for interoperability and sharing Not all projects, and not necessarily a need for both Primary reasons: Reuse Extending availability of existing work Primary routes: Embedding workflows as (distributed) sub-processes Shared abstract (meta) descriptions

27. © 2006 Open Grid Forum 27 Issues Shared meta-language (e.g. XPDL) is a good idea but… Need commitment from workflow developers to implement a binding I want to run a workflow defined in the meta-language Will it really run? Or does it require (aspects of) the environment in which it was initially defined? Depends on the nature of the workflow, e.g. just WS might be easier to port. But what if the client machine expects to receive notifications (i.e. can act as a server)? Introduces concept of modeling/bundling dependencies/runtime Reuse is about getting something for nothing But writing lots of bindings to a meta-language is not getting something for nothing

28. © 2006 Open Grid Forum 28 Issues Semantics How do I dermine what a workflow is/does? Is it semantically the same but functionally different from another? Even if I can embed a foreign workflow into my favorite tool, what about data mediation/massaging? Understanding/mapping inputs/outputs

29. © 2006 Open Grid Forum 29 Approaches Try and solve the world? Impose order on chaos Define how it should be and hope individual projects follow suit Try and solve small things? But within a wider context Fragmented, but not ignorant of other fragments. Start with what is there? Sharing e.g. myExperiment Execution e.g. BES, Atom Meta description e.g. XPDL

30. © 2006 Open Grid Forum 30 Discussion Community Effort? Wed be happy to lead a research document but need volunteers Need at least 5 volunteers not including ourselves … State-of-the-art of workflow interoperability and sharing use cases and proposals Area is vague at present Document would help firm up the area and push things forward.