Service, Grid Service and Workflow Xian-He Sun Scalable Computing Software Laboratory Illinois Institute of Technology Nov. 30, 2006 Fermi Laboratory

Scalable Computing Software (SCS) Lab. Parallel Computers at SCS NU-E UIC ANL NCSA/UIUC Uof C NU-C Star Tap IIT OMNI I-WIRE Distributed Optical Testbed (Grid) Pervasive Computing Environments at SCS

Reduced Complexity & Cost Higher Quality of Service Increased Productivity Increased Efficiency Grid and Utility Computing Improved Resiliency Mimic the electrical power grid

Service Oriented Computing Convergence of Core Technology Standards allows Common base for Business and Technology Services Grid OGSi GT2 GT1 Web HTTP WSDL, SOAP WS-* Have been converging WSRF Started far apart in applications & technology XML BPEL WS-I Compliant Technology Stack Internet computing: Web service Grid computing: Grid service and is merging with WS Pervasive computing: Human centered service Mobile computing: Phone service Computing as a service

Information Service Challenge: Computing as a Service SOC is about separation, sharing, and workflow Sharing (service/resource) Modeling Scheduling: system vs application, replica vs consistency QoS: external task vs local jobs Security Separation (service) Abstraction: personalized service Primary service: Automatic coding Separation of concern Separation of resource: Virtualization Workflow Management

Service Oriented Architecture (SOA) SOA is the special software architecture with services are the key building blocks SOA is basically an application development style using services They are principles or patterns to develop application using services The concept of SOA comes from software research SOA is developed from IT experience over 30 years

What is SOA ? – more detail An architecture that implements business functionality as a set of shared, reusable services Way of designing a software system and its surrounding environment to provide services either to end-user applications, to executable business processes or to other services through published and discoverable service interfaces. Aggregation of components for a business driver Extended bus with shared services service interface being defined separately from implementation and provides service encapsulation and platform/language independence.

The General Service Oriented Architecture (SOA) Service Provider –Provides a stateless, location transparent business service Service Registry –Allows service consumers to locate service providers that meet required criteria Service Consumer –Uses service providers to complete business processes Service Requestor Service Provider Service Registry Publish Find Bind Publish-Find-Bind mechanism

What is Web Service? A software component Identified by unique URI Who can be discovered by other soft.comp web services are a stack of emerging standards that describe a service- oriented, component- based architecture

Key Players - Do you know me ?? –Describe by – WSDL Do you want to find me ?? –Discover in – UDDI Do you want to communicate with me?? –Communicate through– SOAP/XML

Web Service Components Service Provider Service Contract Service Consumer Client Service Registry Register Find Bind UDDI WSDL SOAP

The Grid Computing Infrastructure (“middleware” & “services”) for establishing, managing, and evolving multi- organizational federations Mechanisms for creating and managing workflow within such federations Three key criteria –Coordinates distributed resources … –using standard, open, general-purpose protocols and interfaces … –to deliver non-trivial qualities of service.

Data Grids for High Energy Physics Tier2 Centre ~1 TIPS Online System Offline Processor Farm ~20 TIPS CERN Computer Centre FermiLab ~4 TIPS France Regional Centre Italy Regional Centre Germany Regional Centre Institute Institute ~0.25TIPS Physicist workstations ~100 MBytes/sec ~622 Mbits/sec ~1 MBytes/sec There is a “bunch crossing” every 25 nsecs. There are 100 “triggers” per second Each triggered event is ~1 MByte in size Physicists work on analysis “channels”. Each institute will have ~10 physicists working on one or more channels; data for these channels should be cached by the institute server Physics data cache ~PBytes/sec ~622 Mbits/sec or Air Freight (deprecated) Tier2 Centre ~1 TIPS Caltech ~1 TIPS ~622 Mbits/sec Tier 0 Tier 1 Tier 2 Tier 4 1 TIPS is approximately 25,000 SpecInt95 equivalents

Increased functionality, standardization Custom solutions Open Grid Services Arch Real standards Multiple implementations Web services, etc. Managed shared virtual systems Computer science research Globus Toolkit Defacto standard Single implementation Internet standards The Emergence of Open Grid Standards 2010

Open Grid Services Architecture Everything is a service A standard substrate: the Grid service –A Grid service is a Web service –Standard interfaces and behaviors that address key distributed system issues: naming, service state, lifetime, notification Supports standard service specifications –Agreement, data access & integration, workflow, security, policy, diagnostics, etc. –Target of current & planned GGF efforts Supports arbitrary application-specific services based on these & other definitions

SOA and Web Service SOA mostly defined and explained with some accompanied implementations Web services are a stack of emerging standards that describe a service-oriented, component- based architecture Web services are limited SOA, but they are the only available best practical solution till now SOA and Web service are still evolving each other Web service cannot support all the computing service in its current form

Grid and Web Service Grid? What is the Grid? –Standard, technology, infrastructure, application –Globus or general distributed computing ? Standard –Merging with Web service Application –Large scientific application vs. light business application Technology –Resource sharing vs. service sharing, resource sharing vs. pay for service, coordinate virtual organizations vs. create VOs (very hard), stateful vs. stateless

Information Service Workflow and LQCD Workflow All SOC need the management of workflow Is LQCD computing a SOC? Does LQCD need to follow Web service standard? If yes, we need to support Grid service (GT4) If no, we do not

Workflow template identification & generation Tools Users Workflow Design Build Time (user) Run Time (system) Workflow Execution & Control Interaction with computing Resources workflow change LQCD Middleware Resources Interaction with Information Services Information Services Performance Info Service Reliability Info Service Workflow Enactment Service Workflow Scheduling Data MovementFault Management Workflow I nstantiation LQCD Workflow System

Workflow Management Systems Comparison Functionality –Workflow template identification & generation Tools –Workflow specification –Workflow scheduling & rescheduling –Fault Management –Data Movement –Interaction with monitor system Target Systems –AskalonAskalon –KeplerKepler –Grid Physics NetworkGrid Physics Network

Current Result: the GHS System The GHS (Grid Harvest Service) system GHS is a long-term, application-level performance evaluation and task scheduling system specially designed to handle the resources availability issues for solving large-scale applications. The resource availability could be due to contention or due to fault. The two different causes require different performance modeling and prediction Support rescheduling

GHS System Design Structure Task PartitionTask Scheduling Task Rescheduling Task-Execution Application Monitoring ReservationCompeteBest-Effort CPUNetworkMemory ComputationCommunication Scheduling Prediction Modeling Measurement Resource Management System Monitoring System-level Prediction Application-level Prediction

Rescheduling Algorithm The reason of rescheduling Availability pattern change Fault tolerance New jobs arrive Multi-campaign New milestones

Automated Deployment of Meta-task APST software –AppleS scheduling –NWS prediction Integrating GHS prediction and scheduling into APST –Modify the MetricType and ServiceType data structure in the Meta-data Bookkeeper –Add GHS server to provide information service –Add GhsMetataskSched() –Modify XmlFile parser in the Controller component

Software Released GHS 1.0 –Functionalities for performance prediction, measurement, task allocation, and task scheduling GHS-APST 1.0 –Integrate GHS prediction and scheduling into APST execution management –Add GHS server and GHS daemons for performance data collection and inquiry –Unchanged user interface apstd –heuristc=ghs Tested on SunOS 5.9 and Linux Releases are for contention availability, fault availability is a work in progress.