1. CCGrid 2003, Tokyo, Japan GridFlow: Workflow Management for Grid Computing Junwei Cao ( 曹军威 ) C&C Research Labs, NEC Europe Ltd., Germany Stephen A. Jarvis and Graham R. Nudd Dept. of Computer Science, Univ. of Warwick, UK Subhash Saini NASA Ames Research Center, USA

2. CCGrid 2003, Tokyo, Japan Outline Background – Grid Workflow System Architecture GridFlow User Portal Global Grid Workflow Management Local Grid Sub-workflow Scheduling Fuzzy Timing Techniques Summary Ongoing and Future Work

3. CCGrid 2003, Tokyo, Japan Background – Grid Workflow Workflow Definition WPDL, BPEL4WS, GSFL, ASCI Grid, … Workflow Systems WebFlow, Symphony, GridAnt, BPWS4J, TENT, … Component-based Systems CCA/XCAT, SCIRun, CXML, … Other Systems Condor DAGMan, UNICORE, MyGrid, GEMSS, GridLab, BioOpera, USC Grid failure handling, …

4. CCGrid 2003, Tokyo, Japan Grid Resources Grid Resource: A particular grid resource is a high-end computing or storage resource that can be accessed remotely. Local Grid: A local grid consists of multiple grid resources that belong to one organization. Global Grid: The global grid includes all grid resources that belong to different organizations within a virtual organization.

5. CCGrid 2003, Tokyo, Japan Grid Tasks Task: Tasks are the smallest elements in a grid workflow, e.g. MPI & PVM programs. Sub-workflow: A sub-workflow is a flow of closely related tasks that is to be executed in a predefined sequence on grid resources of a local grid (within one organization). Workflow: A grid application can be represented as a flow of several different activities, each activity represented by a sub- workflow.

6. CCGrid 2003, Tokyo, Japan Grid Management Mapping grid workflows to the global grid Mapping grid sub- workflows to local grids Mapping grid tasks to grid resources

7. CCGrid 2003, Tokyo, Japan System Architecture Global Grid GridFlow User Portal Grid Resources Workflow Management Resource Management (ARMS) Information Services (Globus MDS) Local Grid Sub-workflow scheduling Resource Scheduling (Titan) Performance Services (PACE … ) Grid Users

8. CCGrid 2003, Tokyo, Japan PACE Performance Prediction Application Tools Resource Tools Evaluation Engine Source Code Analysis Object Editor Object Library PSL Compiler CPU Network (MPI, PVM) Cache (L1, L2) HMCL Compiler

9. CCGrid 2003, Tokyo, Japan Titan Resource Scheduling Heuristic Evolutionary Near-optimal: Makespan Idletime Deadlines

10. CCGrid 2003, Tokyo, Japan ARMS Grid Management Agent structure Communication layer Decision-making layer Local management layer Agent hierarchy Service advertisement Service discovery Agent Capability Tables A AA AA Use r

11. CCGrid 2003, Tokyo, Japan GridFlow User Portal

12. CCGrid 2003, Tokyo, Japan Global Grid Workflow Management S 2 startT = 0 exeT = 3 endT = 3 S 1 startT = 0 exeT = 0 endT = 0 S 3 startT = 0 exeT = 5 endT = 5 S 4 startT = 5 exeT = 7 endT = 12 S 5 startT = 5 exeT = 4 endT = 9 S 6 startT = 12 exeT = 0 endT = 12 / 7 / 12 S2S2 S1S1 S3S3 S4S4 S5S5 S6S6 / 5

13. CCGrid 2003, Tokyo, Japan Local Grid Sub-workflow Scheduling Scheduling a flow of tasks onto grid resources within a local grid is very similar to the process that schedules a workflow onto different local grids. There are two challenges: It is a difficult task to provide an accurate prediction on task/workflow start, execution and end times. Multiple tasks from different sub-workflows may require the same grid resource at the same time.

14. CCGrid 2003, Tokyo, Japan Fuzzy Timing Techniques Turning the “prediction accuracy” into a fuzzy concept that is represented using fuzzy numbers. π 1 (τ)=0.5(0,2,6,7) π 2 (τ)=(2,4,4,6)

15. CCGrid 2003, Tokyo, Japan Fuzzy Number Operations latestearliest min max sum

16. CCGrid 2003, Tokyo, Japan Resource Conflict Solving I The start time of a task cannot be configured with the latest end time of its pre-tasks directly, since other tasks exists that may use the same resource at the same time. A first-come possibly-first-serve policy is adopted. This does not order the conflictive tasks explicitly, but adds some information on degrees of possibilities of task start times.

17. CCGrid 2003, Tokyo, Japan Resource Conflict Solving II All possible start sequences are considered and are combined to provide an estimation of the end time.

18. CCGrid 2003, Tokyo, Japan Summary GridFlow is a prototype grid workflow management system, focusing on grid workflow simulation and scheduling. GridFlow is based on a specific grid resource management infrastructure implemented using agent-based methodologies and performance- driven scheduling technologies. Making grid workflow management a reality also requires to address general grid computing challenges: openness, standards, security and QoS support.

19. CCGrid 2003, Tokyo, Japan Ongoing Work – Applications Developing grid enabled medical simulation services (GEMSS) using GT3 Developing grid performance services based on historical information analysis Developing medical application workflows using BPEL4WS Target Object Scanning & Preprocessing Numerical Modeling Analysis, Diagnosis, Design HPC Simulation

20. CCGrid 2003, Tokyo, Japan Future Work – Agile Computing Workflow techniques – one of keys for next generation agile (grid) computing Flexibility (Performance, Adaptation, QoS, Individualization) Efficiency (Cheap, Large-scale, Pervasive, Continuous, Massive) Cluster Computing HPC Supercomputing Grid Computing P2P Computing Internet Computing Agile (Grid) Computing

21. CCGrid 2003, Tokyo, Japan For More Information http://www.dcs.warwick.ac.uk/~hpsg/ http://www.ccrl-nece.de/~cao/ http://www.ccrl-nece.de/gemss/ http://www.agilecomputing.org/ mailto:cao@ccrl-nece.de