Dynamic Service Aggregation in Heterogeneous Grids

1
Dynamic Service Aggregation in Heterogeneous Grids

• Stavros Isaiadis and Vladimir Getov
• University of Westminster
• HSCS PhD Workshop, 29th June 2007
• s.isaiadis_at_wmin.ac.uk, v.s.getov_at_wmin.ac.uk

2
Outline

• Overview/Background
• Hybrid Grid Systems
• Lightweight Server-side Container (LSC)
• Aggregator Framework
• Case Study
• Evaluation
• Conclusion

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Outline

• Overview/Background
• Hybrid Grid Systems
• Lightweight Server-side Container (LSC)
• Aggregator Framework
• Case Study
• Evaluation
• Conclusion

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What is the Grid?

• A distributed computing infrastructure that
  enables on-demand, cross-organizational resource
  sharing -a virtual supercomputer?

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Objectives

• Integration of mobile and small-scale devices
  into Grid systems as service providers (and not
  just consumers!)
• Extend the Grid towards the less powerful but
  more flexible end of the spectrum
• Encapsulate the inherent dynamicity and provide
  high-level views and programming abstractions
• Ultimate vision A truly pervasive hybrid Grid
  system

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Why Mobile and Small Devices?

• Unique Functionality
• context and location awareness
• multimedia cameras
• intelligent wireless sensors
• Global Positioning Systems
• Flexibility
• Extend to new geographical areas
• Move business outside
• Interactive and Personalized Services
• With mobile phones, administrators are always
  near their services
• Attach status and context to services

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Outline

• Overview
• Hybrid Grid Systems
• Lightweight Server-side Container (LSC)
• Aggregator Framework
• Case Study
• Evaluation
• Conclusion

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Classes of Hybrid Systems

• mobile interfaces to grid resources
• where mobile devices are merely interfaces to
  functionality available in the Grid system, and
  do not contribute any services.
• exploitation of raw resources
• focus is on distributing applications for
  parallel execution usually requiring the
  partitioning of the application into small
  independent tasks.
• exploitation of services and flexibility
• focus is on supporting mobile services in a SOA
  system, while also enabling small-scale devices
  to contribute services towards a fully integrated
  infrastructure.

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Hybrid Systems
Application Client, User Tools
Developer
Application Layer
Fabric Layer
Mobile and Small-Scale Devices
Typical Static Services
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Challenges

• Grid systems have typically evolved around High
  Performance Computing. As a result, Grid
  developers have assumed
• A plethora of available static resources
• Fast and reliable networking infrastructure
• Currently very restricted and very few service
  middleware for small scale devices
• Based on Web Services (slow and resource
  demanding)
• Java RMI (restrictions and dependencies)
• Cannot consider each mobile device as a full Grid
  system member!
• Very unreliable
• Limited individual contribution

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Contribution

• A Lightweight Service Container suitable for
  limited devices
• Performance-oriented
• No dependencies
• Easy deployment
• But non-interoperable, low-level. What do we do?
• Related Work
• Mobile OGSI.NET
• Obsolete, restricted model, complex deployment
• Microservices
• Very complex deployment, not very fast (WS-based)
• Racoon
• Promising for small Web Services (still in
  progress), but not very fast
• WSKPeer
• Promising hybrid Service/P2P approach, work in
  progress no workable version

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Contribution (contd.)

• An Aggregator framework to enable the efficient
  integration of mobile devices. An Aggregator
  provides
• A proxy to a group of heterogeneous and mobile
  fabric services
• an abstraction layer that hides the dynamicity
  and heterogeneity of the mobile services
• a high-level view of a virtually stable and
  reliable entity, despite the unreliable nature of
  the inner fabric services
• Related Work
• ?

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Contribution (contd.)
Aggregators
Development API
Proxy Layer
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Outline

• Overview
• Hybrid Grid Systems
• Lightweight Server-side Container (LSC)
• Aggregator Framework
• Case Study
• Evaluation
• Conclusion

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Lightweight Server-side Container (LSC)

• Small CPU and memory footprint
• Simpler services
• not complex operations
• no build in support for complex data types
  (currently)
• No software dependencies
• only J2ME running!
• for easy deployment
• Permanent and Stateful approach
• To support context-awareness
• To simplify lifecycle management
• To reduce concurrent client connections and thus
  resource requirements
• Friendly GUI for easy service registration

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LSC Stack
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Outline

• Overview
• Hybrid Grid Systems
• Lightweight Server-side Container (LSC)
• Aggregator Framework
• Case Study
• Evaluation
• Conclusion

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Aggregator Framework

• Design Requirements
• Encapsulate the big cardinality of the mobile
  domain
• Provide reliability and availability
• Encapsulate heterogeneity and dynamicity
• Must enable a high-level abstract view

VIRTUAL CLUSTER
HTTP/SOAP
TCP/LSC
CLIENT
PROXY
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Aggregator/Virtual Clusters Architecture
Application Client, User Tools
Developer
Application Layer
Aggregator Platform Service Interfaces
Development API
Aggregator Platform Services
Collective Layer
VC Platform/ Proxy Layers
Fabric Layer
Groups of Mobile and Small-Scale Devices
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Dynamic Service Aggregation
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Outline

• Overview
• Hybrid Grid Systems
• Lightweight Server-side Container (LSC)
• Aggregator Framework
• Case Study
• Evaluation
• Conclusion

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Case Study

• Dynamic Content Aggregation from Multiple
  Heterogeneous Mobile Sources
• Phase 1 providers must register their services
  with an Aggregator
• Phase 2 registered services are automatically
  activated when they are within the
  neighbourhood of an Aggregator
• Phase 3 clients can now use that Aggregator (WS)
  to gather content without knowledge of the
  underlying fabric level details

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Phases 1 and 2 Registration and Activation

• Providers specify the shared services
• Server-side Framework (WS, RMI, LSC, Other)
• Implementation class
• Interface location
• Human readable description
• They can then enable sharing on the press of a
  button
• Services are discovered by the relevant
  Aggregator and activated automatically
• Services are now shared!

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Phase 3 Invocation
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Outline

• Overview
• Hybrid Grid Systems
• Lightweight Server-side Container (LSC)
• Aggregator Framework
• Case Study
• Evaluation
• Conclusion

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LSC Evaluation Performance Testing
Type Base Model Memory OS Server-side framework
Laptop A 2.2GHz Intel 1GB Win XP Tomcat/Axis, RMI, LSC
Laptop B 1.6GHz AMD 512MB Win XP Tomcat/Axis, RMI, LSC
Smartphone Sony P990i 128MB Win Mobile Microservices, RMI-OP, LSC
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LSC Evaluation Resource Requirements
Component Size
vcluster-mobile.jar 42 KB
LSC.jar 31 KB
Service-registry.xml 2 KB
startup scripts 1 KB
Total 76 KB
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Outline

• Overview
• Hybrid Grid Systems
• Lightweight Server-side Container (LSC)
• Aggregator Framework
• Case Study
• Evaluation
• Conclusion

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Conclusions

• The LSC framework manages to marry the high
  performance of low-level TCP sockets with the
  interoperability of the standards-based Web
  Services paradigm
• Evaluation has shown that resource requirements
  are minimal, and there are no software
  dependencies or complex installation procedures
• The Aggregator framework
• enables high-level abstract views of the mobile
  devices
• Provides a virtually stable and reliable virtual
  entity despite consisting of unreliable fabric
  services
• With the rapid evolution of mobile computing and
  related advances, the time is right to provide
  the foundations for truly pervasive systems

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Thank You!

• Questions?
• The Virtual Clusters Project page
  http//www.isaiadis.com/vc/
• Please forward any suggestions, questions,
  comments to
• s.isaiadis_at_wmin.ac.uk