Nadia Ranaldo Eugenio Zimeo

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Nadia Ranaldo - Eugenio Zimeo
Grids_at_Work 2008 ProActive and GCM User Group
Orchestrating Services based on Active Objects
and Grid Components

• Department of Engineering
• University of Sannio Benevento Italy

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Outline

• Research Context
• Composition-based approaches for Grid
  applications
• Service orchestration and choreography
• The SAWE Workflow Enactment System
• Orchestration of ProActive/GCM components
• Distributed data flow
• Dynamic binding
• Future directions

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Grid Applications Composition-based approaches

• Complex scientific and business applications as
  composition of reusable, independent and
  cooperating software units in large-scale
  distributed systems
• Heterogeneity, dynamicity, scalability, security,
  etc.
• Composition in space
• Structural relations and interactions among units
• Code re-use
• Tightly-coupled systems (closed world,
  well-defined knowledge)
• Favoured by component-based architectures
• Composition in time
• Units ordered with respect to temporal
  dependences
• Efficient scheduling and resource usage
• Loosely-coupled systems (open world incremental
  knowledge, late binding)
• Favoured by service-oriented architectures
• Exploit the advantages of both the approaches for
  Grid applications

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Composition in time Orchestration of Services

• Analysis
• Hypothesis
• Related work
• Propose experiments

• Define steps
• Prototype computing systems
• Perform experiments
• Data collection

• Presentation
• Dissemination

• Visualization
• Validation
• Adjust experiment
• Refine hypothesis

Graphical Workflow Editor
Workflow Engine (WE)

• scheduling
• data movement
• monitoring

Experiment processes
Grid middleware functionalities
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Workflow engines for e-science

• Taverna
• Web services based language Scufl
• FreeFluo engine
• Graphical viz of workflow

• Triana
• Components
• Task graph
• Data/control flow

• Kepler
• Actor,director
• MoML
• Execution models
• Ptolemy II
• Web Services

• Pegasus
• Based on DAGMan
• VDL
• DAG

and many others

• DAGMan
• Computing tasks
• DAG

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Towards Service Choreography Centralized
Orchestration Approach

• A workflow is managed by a central workflow
  engine
• Late binding
• Efficient scheduling and QoS criteria fulfillment
  performed interacting with resource management
  services (matchmaker, broker, etc.) and parallel
  execution frameworks (skeletons, parallel
  libraries, etc.)

• Centralized control and data flow
• Completely independent services
• High network overhead

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Towards Service Choreography Distributed
Orchestration Approach

• P2P network of services for discovery,
  composition and execution
• Each activity described from the individual
  perspective of its participating services
• Better support to dynamic workflows

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Semantic and Autonomic WE (SAWE)

• Compliant to WfMC specification
• XPDL, BPEL
• Configurator
• Defines process description
• Engine
• Functional management of the process
• Manager
• Monitors engine, running activites, environment
• Decides actions to react to events, environmental
  changes, etc.

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Workflows of ProActive/GCM Components

• A task is performed by a ProActive/GCM component
  (typically a composite component), which exports
  a well defined functionality

• Grid Component Model (GCM)
• Based on Fractal
• Target Grid context
• Parallel computation, deployment, dynamicity,
  autonomous behaviuor
• Lookup of already running components
• Deployment at run-time

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Early-Start Pattern

• Task anticipation exploiting asynchronous
  invocations and futures
• Default future update strategy (data flow follows
  invocation flow)
• Distributed data flow through futures
• The lazy message-based update strategy

A
A (run)
A
Engine
B
B (run)
B (block)
B

• No interactions among tasks and the engine for
  data updating

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Workflows of ProActive Components Dynamic Binding

• Dynamic binding (abstract modelling) of ProActive
  tasks adopting the ProActive Scheduler

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Future Directions

• Distributed data flow based on the lazy
  message-based future update strategy
• Dynamic binding of ProActive/GCM components
• QoS description through semantic annotations of
  components for dynamic binding based on
  user-defined QoS criteria
• Monitoring of ProActive/GCM components for
  autonomic behaviour of workflows

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Thanks for your attention!

• For further contact
• Nadia Ranaldo ranaldo_at_unisannio.it
• Eugenio Zimeo zimeo_at_unisannio.it