Dynamic Service Aggregation in Heterogeneous Grids Stavros Isaiadis and Vladimir Getov University of...

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Dynamic Service Aggregation in Heterogeneous Grids

Stavros Isaiadis and Vladimir Getov

University of Westminster

Heraklion, Crete, 13th June 2007http://www.coregrid.net

[email protected], [email protected]

European Research Network on Foundations, Software Infrastructures and Applications for large scale distributed, GRID and Peer-to-Peer Technologies 2

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

Outline



Outline

Overview/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

• Aggregation of small, mobile, and heterogeneous services

• Encapsulate the inherent dynamicity and provide high-level views and programming abstractions

• Ultimate vision: A truly pervasive hybrid Grid system


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




Outline

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 resourcesfocus is on distributing applications for parallel execution usually requiring the partitioning of the application into small independent tasks.

• exploitation of services and flexibilityfocus is on supporting mobile services in a SOA system, while also enabling small-scale devices to contribute services towards a fully integrated infrastructure.


Hybrid Systems


Application Client, User Tools, SOA MWApplication Client, User Tools, SOA MW DeveloperDeveloper

Mobile and Small-Scale DevicesMobile and Small-Scale Devices

Fabric Layer

Application/User Tools/ SOA Middleware Layer

Challenges• Grid systems have typically evolved around HPC and e-Science

• Assumed a plethora of static resources• Fast and reliable networking infrastructure

• Even with suitable solutions it is unreasonable to assume that everyone will adopt the same framework

• In dedicated and static environments certain guidelines and policies can be enforced but: in dynamic environments that aim at agility, opportunistic computing, flexibility and mobility, imposing such restrictions is unrealistic

• Providers should choose the framework that suits their devices (but results in heterogeneity

• WS for interoperability and easy integration• RMI for a bit of performance and interoperability• Proprietary performance-oriented methods?• Something else???

• Cannot consider each mobile device as a full single member!– Very unreliable– Limited contribution


Contribution• A Lightweight Server-side Container suitable for limited devices

• Socket-based

• High performance

• 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


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:• ?


Contribution (contd.)


Mobile and Small-Scale DevicesMobile and Small-Scale Devices

Fabric Layer



AggregatorsAggregators Development APIDevelopment API

Proxy Layer



Outline

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


LSC Stack


Service RegistryService Registry

Server Socket Listener

Server Side ComponentsServer Side Components

Java Bean

Java Bean

Java Class

Java Class

Other JavaOther Java

SelectorSelector

Server Request Handler

Service ContainerService Container

Socket Communicator

Service Request Translator

Service InterfacesService Interfaces

TCP Socket

ProxyMobile Device



Outline

Aggregator Framework

Integrated hybrid systems issues:– Encapsulate the big cardinality of the mobile domain– Provide reliability and availability– Encapsulate heterogeneity and dynamicity

LSC-related issues:– Must enable a high-level view– Must provide interoperability


HTTP/SOAP

TCP/LSC

PROXYCLIENT

VIRTUAL CLUSTER

Aggregator/Virtual Clusters Architecture



Aggregator + Platform Service InterfacesAggregator + Platform Service Interfaces

Development APIDevelopment API

Groups of Mobile and Small-Scale DevicesGroups of Mobile and Small-Scale Devices

Collective LayerCollective Layer

Fabric Layer

Aggregator + Platform ServicesAggregator + Platform Services

VC Platform/ Proxy Layers


Dynamic Service Aggregation




Outline

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


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!


VC Platform/ Proxy LayersVC Platform/ Proxy Layers

Phase 3: Invocation




Outline

LSC Evaluation: Performance Testing

Type Base Model Memory OS Server-side frameworkLaptop 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


LSC Evaluation: Resource Requirements

Component Sizevcluster-mobile.jar 42 KB

LSC.jar 31 KB

Service-registry.xml 2 KB

startup scripts 1 KB

Total 76 KB




Outline

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


Related Resources

Publications:

http://www.isaiadis.com/publications/

International Science Grid This Week:

http://www.isgtw.org/

(6th June Edition)


Ευχαριστώ!

Questions?

The Virtual Clusters Project page: http://www.isaiadis.com/vc/

Please forward any suggestions, questions, comments to:

[email protected]


Dynamic Service Aggregation in Heterogeneous Grids Stavros Isaiadis and Vladimir Getov University of...

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