Interaction model of grid Interaction model of grid services in mobile grid services in mobile grid

environmentenvironment

Ladislav PesickaLadislav Pesickapesicka@kiv.zcu.czpesicka@kiv.zcu.cz

University of West BohemiaUniversity of West Bohemia

The main topicsThe main topics

Using mobile devicesUsing mobile devices – To access computation gridTo access computation grid– To be a part of the gridTo be a part of the grid

SSupport of mobile agentsupport of mobile agents – Disconnected computingDisconnected computing– MigrationMigration

ContentContent

Computation gridsComputation grids – short overviewshort overview

Mobile devicesMobile devices– restrictionsrestrictions

The role of mobile agentsThe role of mobile agents– how to helphow to help– Interaction modelInteraction model

GridsGrids

In mid. 1990s, most development in last In mid. 1990s, most development in last years –> web services, XMLyears –> web services, XML

Distributed computing infrastructure for Distributed computing infrastructure for advanced science and engineeringadvanced science and engineering

Establish Establish virtual organizationsvirtual organizations (VO)(VO)

Manage security, trust, privacyManage security, trust, privacy

Manage and monitor distributed resourcesManage and monitor distributed resources

Virtual Organization (VO)Virtual Organization (VO)

Real organizationsReal organizations can participate in one or more VOcan participate in one or more VO

Resource sharingResource sharing – conditional – conditional (constraint given by resource owner) (constraint given by resource owner) when, where and what can be donewhen, where and what can be done

Member servicesMember serviceswhat resources able to access, the “quality”, what resources able to access, the “quality”, and the policies that govern accessand the policies that govern access

StandardsStandards

OGSA (Open Grid Service Architecture)OGSA (Open Grid Service Architecture)defines what Grid services are, no technical defines what Grid services are, no technical and detailed specificationsand detailed specifications

OGSI (Open Grid Service Infrastructure)OGSI (Open Grid Service Infrastructure)formal and technical specificationformal and technical specification

Globus Toolkit 3 (http://www.globus.org)Globus Toolkit 3 (http://www.globus.org)implementation of OGSIimplementation of OGSI

Open Grid Services Infrastructure Open Grid Services Infrastructure (OGSI)(OGSI)

OGSIOGSI defines mechanisms for creating, defines mechanisms for creating, managing, and exchanging information among managing, and exchanging information among entities called entities called Grid servicesGrid services

Grid serviceGrid service - a Web service that conforms to - a Web service that conforms to a set of conventions (interfaces and behaviors) a set of conventions (interfaces and behaviors) that define how a client interacts with that define how a client interacts with a Grid servicea Grid service

Grid serviceGrid service

Grid service factoriesGrid service factories concept conceptresponsible for creating and destroying of objectsresponsible for creating and destroying of objectsClient performs operations on the same instance of GsClient performs operations on the same instance of GsOne instance – used mostly by one clientOne instance – used mostly by one clientService dataService data elements – state of the service elements – state of the service

Factory:

-Create instance

-Destroy instance

Grid service – namingGrid service – naming

Distinguish among different instancesDistinguish among different instances

GSHGSH (Grid Service Handler) (Grid Service Handler) - naming, URI - naming, URI

http://localhost:8080/ogsa/services/samples/counter/basic/http://localhost:8080/ogsa/services/samples/counter/basic/CounterFactoryService/hash-31889293-1079702176271CounterFactoryService/hash-31889293-1079702176271

GSRGSR ( (GridGrid ServiceService Reference) Reference)in the form of WSDL documentin the form of WSDL documentdescribes what the clients need to know describes what the clients need to know to be able to communicate with grid serviceto be able to communicate with grid service

Globus Toolkit 3Globus Toolkit 3

Grid service middleware Grid service middleware

Implementation of Implementation of corecore grid services based on grid services based on OGSI – OGSI – pure Javapure Java language, other services in language, other services in C languageC language

Important services:Important services:– GRAMGRAM (Globus Resource Allocation Manager) (Globus Resource Allocation Manager)– GridFTPGridFTP (File Transfer Protocol, similar to FTP) (File Transfer Protocol, similar to FTP)– MDS3MDS3 (Monitoring and Discovery Service) (Monitoring and Discovery Service)– GSIGSI (Grid Security Infrastructure) (Grid Security Infrastructure)

Grid - resourcesGrid - resources

Provides Provides list of available resourceslist of available resources together with its together with its characteristicscharacteristics

These characteristics are given by These characteristics are given by available available SDESDE (Service Data Elements)(Service Data Elements), , just its values can change - predefinedjust its values can change - predefined

RSL (Resource Specification Language)RSL (Resource Specification Language)

In the form of pairIn the form of pair (Atribute, value) (Atribute, value)

Resource metricResource metric or or configuration parameterconfiguration parameter

Used to specify requirements of the applicationUsed to specify requirements of the application

Executable, directory, stdin, stdout, …Executable, directory, stdin, stdout, …

Globusrun –r node –o “&(executable=/bin/ls)”Globusrun –r node –o “&(executable=/bin/ls)”

Resource allocationResource allocation

Deep knowledge ofDeep knowledge of– Client demandsClient demands

(computational and memory allocation demands)(computational and memory allocation demands)

– Offer of given resourceOffer of given resource(speed, available memory)(speed, available memory)

Work with Work with incomplete knowledgeincomplete knowledgemissing or just estimated informationmissing or just estimated information(computation power (computation power vs.vs. supposed lifetime) supposed lifetime)

Do not Do not know requirements of “future” clientsknow requirements of “future” clients

Mobile devices - restrictionsMobile devices - restrictions

Host resourcesHost resources(computation capability, memory, limited power sources)(computation capability, memory, limited power sources)

Network resourcesNetwork resources(narrow bandwidth, latency, lost of signal, costs)(narrow bandwidth, latency, lost of signal, costs)

Security issuesSecurity issues(security problems in wireless networks)(security problems in wireless networks)

InteroperabilityInteroperability(different OS, HW and SW equipment)(different OS, HW and SW equipment)

AvailabilityAvailability(power-loss, switching off initiated by the user)(power-loss, switching off initiated by the user)

Mobile agent supportMobile agent support

To obtain resource characteristicsTo obtain resource characteristics(need to gain more information then SDEs)(need to gain more information then SDEs)

To control the computation To control the computation instead of mobile device instead of mobile device(support for disconnected computing)(support for disconnected computing)

Perform some actions on the mobile device Perform some actions on the mobile device (computation, searching) (computation, searching) (MD as computation resource)(MD as computation resource)

System architectureSystem architecture

Home networkHome network, , Foreign networkForeign network

Grid environmentGrid environment – VO – VO

Home baseHome base inside Home network inside Home network

MA hosting environmentMA hosting environment available in available in resource nodes of the foreign networkresource nodes of the foreign network

Stationary agentStationary agent in MD – control in MD – control communication with home basecommunication with home base

Home baseHome base

One node in the home networkOne node in the home network(optionally visitors base in foreign network)(optionally visitors base in foreign network)

More nodes can be More nodes can be home base candidateshome base candidates (against the failure), communicate together to (against the failure), communicate together to know which one servers the given mobile deviceknow which one servers the given mobile device

Mobile device – a priority list of IPs, or DNS Mobile device – a priority list of IPs, or DNS names of the candidatesnames of the candidates

Home baseHome base

Main tasks:Main tasks:– Repository of agentsRepository of agents owned by the users that owned by the users that

could be sent to the networkcould be sent to the network– Agent management systemAgent management system– Messages queueMessages queue to collect notices and logs to collect notices and logs

for the client (MD), at the time it is for the client (MD), at the time it is disconnecteddisconnected

The model of interactionsThe model of interactions

Home network Foreign network

1,4

2

3

Mobile device (dynamic IP)

Home base (static IP)

The choice of most suitable resource1 request, 2 MA sent, 3 MA returns, 4 response

Control of the computation based on MAControl of the computation based on MA

ClientClient sends request to the home base sends request to the home base

Home baseHome base – agents repository, including: – agents repository, including:– Agents to find proper resource nodeAgents to find proper resource node– Agents capable to control comp. on the foreign node Agents capable to control comp. on the foreign node

(where they will be sent)(where they will be sent)

FeedbackFeedback – agent communicates with home – agent communicates with home base or directly with mobile nodebase or directly with mobile node

Using Using certificatescertificates (VO agreement) (VO agreement)

MD as computation resourceMD as computation resource

Mobile device as Mobile device as grid-enabledgrid-enabled node nodeMobile device includes Mobile device includes environment toenvironment tohost mobile agentshost mobile agents

Lifetime management Lifetime management (power down)(power down)

AccountingAccounting – e.g. communication costs – e.g. communication costs (WiFi connection) in foreign network can be paid (WiFi connection) in foreign network can be paid in the form of computational cycles in the form of computational cycles (powerful notebooks)(powerful notebooks)

Some problems and featuresSome problems and features

Availability of suitable Availability of suitable J2MEJ2ME (or (or J2SEJ2SE) ) environment for different kind of mobile devicesenvironment for different kind of mobile devices

Availability and stability of mobile agents hosting Availability and stability of mobile agents hosting environment for the mobile devicesenvironment for the mobile devices

Take care about robustness, security, Take care about robustness, security, communication overhead of the systemcommunication overhead of the system

ConclusionConclusion

Mobile devicesMobile devices– Demand for mobile access to the grids Demand for mobile access to the grids – They are more and more powerful They are more and more powerful

(source of information, computation cycles)(source of information, computation cycles)

Mobile agentsMobile agents– Agent based gridAgent based grid– Monitoring of gridsMonitoring of grids

Mobile gridsMobile grids– As energy outlets – just connected and obtain proper As energy outlets – just connected and obtain proper

computation power and resources anywhere anytimecomputation power and resources anywhere anytime

Thank You for Your AttentionThank You for Your Attention

pesicka@kiv.zcu.czpesicka@kiv.zcu.cz