Quality-awareSelf-ManagementforService
ProcessesinService-OrientedArchitectures
SteffenBleul
KasselUniversity,DistributedSystems,bleul@vs.uni-kassel.de
Abstract.OneofthesalientfeaturesofService-OrientedArchitectures
isthatservicescanbedeployedandremovedatruntime.ButservicereplacementandmanagementforserviceprocessesisademandingtaskincomplexIT-Systems,especiallyunderadditionalconstraintslikeop-timizingtheQualityofServiceofaserviceprocess.Aself-managingsystemisdesiredbutmissing.Wehavealreadyachievedself-healingandself-optimizationwithourservicebrokeringsystem.WeapplyontologiestodiscoverservicealternativesandtheirQoS.Inthispaperwenotonlypresentourworkonquality-awareservicediscoverybutalsoproposeaself-manageableinfrastructureforserviceprocesses.Theinfrastructurecanbedynamicallyinstantiated,configuredandboundtomanagementendpointswithsemanticservicediscovery.Theapproachnotonlyauto-matesthebindingofservicemanagementsystemsofmultiplevendorsbutalsotheSLAmonitoringandthead-hocintegrationofservicesinserviceprocesses.
1Introduction
AService-OrientedArchitecture(SOA)istheidealarchitectureforhighlydy-
namicsystemsespeciallyforcomplexenterpriseIT-Systems.Thebusinesslogic
ofanenterprisecanbedirectlyimplementedasservicesandarrangedtobusiness
processesintheformofservicecompositions.ASOAdirectlyreflectstheneedfor
easyintegration,reusabilityandchangewithoutaffectingthecourseofbusiness.
WhenitcomestoServiceManagement,anyarchitecturefordistributedappli-
cationsforfeitsitssalientadvantageswithoutsomekindofself-management.
Servicemanagementmustensureacertainlevelofqualitywhichrequiresfast
recognitionandhandlingofserviceproblemsthroughouttheSOA.
Animportantbuildingblockforaself-manageablesystemistheSemantic
Web.Wehavedevelopedontologiestodescribeserviceprocesses,servicesand
theirQoS.Theyallowautomaticquality-awarebindingofservicestoservice
processesatruntime[1].Whereassemanticservicediscoveryisimportantfor
ServiceManagementitisjustthefirststeptowardsself-management.Inthis
paperwepresentanapproachforaself-manageableinfrastructure.Newlyde-
ployedserviceprocesses,theirmanagementendpointsandmanagemententities
areautomaticallyinstantiatedandconnected.Weapplysemanticservicedis-
coveryinordertosupportautomaticconfigurationoftheinfrastructure.The
requiredmanagementmodelandcomponentsareintroducedinSection2.We38SteffenBleul
presentourachievementsonquality-awaresemanticservicediscoveryforservice
processesinSection3.InSection4wediscussrelatedworkandthepapercloses
withaconclusioninSection5.
2Self-ManagementforServiceProcesses
Ourachievements(seeSection3)alreadyenableself-propertiesinsideaSOA
andcanbeappliedtoself-management.Theoverallgoalisaself-managingdis-
tributedinfrastructureforquality-awareserviceprocessmanagementbyusing
semanticservicediscoverytoplugmanagementcomponentsofserviceconsumers
andservicevendorstogether.Serviceprocessesmustbedeployableatruntime
andservicesmustbedynamicallyfoundandboundtotheserviceprocess.More-
over,servicesmustbemanagedwithrespecttotheirQoSwhichalsorequires
dynamicinstantiationandmonitoringofServiceLevelAgreements(SLA).Man-
agementoftheseservicesmustbehandledinaplatform-andorganisational-
independentwaybyprovidingruntimeinformationtoandacceptingmanage-
mentactionsfromallparticipatingorganisations.Withoutdoubt,theimpactof
thisworkisdependentontheabilitytointegratetheresultingsystemincurrent
IT-Organisations.Therefore,thedynamicconfigurationoftheinfrastructurewill
havetheabilitytoinvolvethelocalorganisation’sreporting,changemanagement
ormanualadministration.
ThenecessarydistributedinfrastructureforSLAandservicemonitoringand
ServiceManagementmustevenbeabletobedynamicallyinstantiatedinorder
tosupportservicereplicationandintegrationofnewlyoutsourcedorboughtser-
vices.ThisrequiresageneralmodelforServiceManagement.WedescribeService
Managementasaninteractionbetweenmanagementinterfaces.Themanage-
mentinterfacesdealwithprovidinginformationaboutaservicestate,processing
serviceinformationortosubmitmanagementactionstochangeaservice’sstate.
Theinteractionbetweenmanagementinterfacesaredescribedbyitsexchanging
messagesconsistingofsensorinformationandmanagementactions.Moreover,
serviceprocessmanagementistheaccumulationofallmanagementinterfaces
andinteractionsoftheparticipatingservicesandservicemanagers.Aservice
processcanbemanagedinaplatform-andorganisational-independentwayby
routingsensoryinformationtoanarbitraryamountofmanagemententitiesand
byredirectingtheresultingmanagementactionstotheServiceManagementin-
terfaces.Inourmodelwedefinethreetypesofservicestoenableaself-managing
infrastructure:
–Sensor:Asensorisaservicethatproducesstateinformationaboutaservice
orserviceprocess.Asensorproducesitsoutputindependentlyofothersen-
sors(lowlevelsensors)orisinneedoftheinputofothersensors(highlevel
sensors).Forinstancealowlevelsensorsendstheavailabilityinformation
ofasingleservicetoshighlevelsensorthatevaluatestheavailabilityofthe
relatedserviceprocesses.
