Table Of ContentService Level Agreement Mediation,
Negotiation and Evaluation for
Cloud Services in Intercloud Environments
vorgelegtvon
M.Sc. Dipl.-Ing. (FH)
AlexanderStanik
geb. inBerlin
vonderFakulta¨tIV-ElektrotechnikundInformatik
derTechnischenUniversita¨tBerlin
zurErlangungdesakademischenGrades
DoktorderIngenieurwissenschaften
-Dr.-Ing. -
genehmigteDissertation
Promotionsausschuss:
Vorsitzender: Prof. Dr.-Ing. StefanTai
Gutachter: Prof. Dr. habil. OdejKao
Prof. Dr.-Ing. GeroMu¨hl
Prof. Dr. MatthiasHovestadt
TagderwissenschaftlichenAussprache: 11. April2016
Berlin2016
Acknowledgement
I would like to thank all the people who supported me during my studies and made this PhD
thesis possible. I especially want to thank my advisor Odej Kao for his guidance and inviting
metoworkinhisgroup. Thanksformakingthisjobprobablythebestinmylife. Specialthanks
also go to the entire working group “Complex and Distributed IT Systems” at TU Berlin for
the awesome past five years. I also thank my former colleague Matthias Hovestadt for his
guidance for finding this topic of my PhD thesis. And also many thanks go to Anto´nio Cruz,
Gregory Katsaros, Mareike Ho¨ger, Andreas Kliem, Marc Ko¨rner, Florian Feigenbutz, Fridtjof
Sander,OliverWa¨ldrich,AndreasWeissandWolfgangZieglerforinsightfuldiscussionsabout
theresearch.
Aspecialthankstomyfamilyfortheirsupportduringallthetime. Wordscannotexpresshow
gratefulIamtomymotherIreneandmyfatherRobertforallofthesacrificesthatyou’vemade
on my behalf. You educated me and have made me to the person who I am today. Thanks for
alwaysofferingsupportandlove,moreover,helpingmewheneverIneededyou.
Finally, special thanks goes to my dear wife Jeanette and my kids Maximilian, Charlotte, and
Anastasia for their endless love and patience especially during writing this thesis. You spent
sleepless nights with and unfortunately also sometimes without me. You were always my
supportinthemomentswhentherewasnoonetoanswermyqueries. Imarriedthebestperson
out there for me. These past several years have not been an easy ride, both academically and
personally, but you and our kids were always there and unconditionally loved me during my
goodandbadtimes. Thanks!
Abstract
The management of today’s service level agreements on the cloud market is often nontrans-
parent and inefficient for the customer and the provider. However, service level agreements
arecrucialforestablishingtrustbetweenallparticipants,especiallyforcompanieswhosesuc-
cess depends on the purchased cloud service with its appropriated service quality. This thesis
aims to improve the current situation on the cloud market in terms of providing architectural,
methodological,andfunctionalapproacheswithstandard-basedprotocolspecificationsfordy-
namic and situational service level agreement management. Therefore, this thesis analyses
and presents current service level agreement standards and existing implementations. Based
on these results, a set of concepts and approaches for agreement and service mediation are
developedandexperimentallyevaluated.
However, all of these existing approaches either target a specific community or implement
broker services with just a closed product portfolio for services delivered by a small set of
providers. In order to establish a trusted provider overlay network as global marketplace for
cloud services, where all participants can federate by nature, expose their product offer, and
reachawidercustomercommunity,thisthesisintroducesanovelconceptforintercloudagree-
ment mediation. The Agreement-Mediators in this global provider network act as neutral and
autonomous entities in the cloud market and rise trust between independent providers and be-
tweenprovidersandcustomers. Thelanguageandprotocolforsearching,negotiating,andes-
tablishingservicelevelagreementsisspecified,developed,andevaluated. Theoutcomesofthis
thesis aim to increase efficiency and effectiveness for discovering cloud services of indepen-
dent providers and the management of service level agreements established for each business
relationship. The experimental results show significant improvements in terms of efficiency,
scalability,andflexibility.
Contents
1. Introduction 1
1.1. ProblemDefinition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2. Contribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3. OutlineoftheThesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2. SLA Fundamentals and Definitions 9
2.1. Disambiguation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2. ApproachesforServiceLevelAgreements . . . . . . . . . . . . . . . . . . . . 11
2.3. WS-Agreement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.3.1. WS-AgreementModel . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.3.2. WS-AgreementProtocol . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.3.3. WS-AgreementFactoryService . . . . . . . . . . . . . . . . . . . . . 15
2.3.4. WS-AgreementAgreementService . . . . . . . . . . . . . . . . . . . 16
2.3.5. WS-AgreementLanguage . . . . . . . . . . . . . . . . . . . . . . . . 16
2.4. WS-AgreementNegotiation . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.4.1. WS-AgreementNegotiationModel . . . . . . . . . . . . . . . . . . . 20
2.4.2. WS-AgreementNegotiationProtocol . . . . . . . . . . . . . . . . . . 22
2.4.3. WS-AgreementNegotiationLanguage . . . . . . . . . . . . . . . . . . 23
3. Standards and Implementation Analysis 25
3.1. WS-AgreementDependencyAnalysis . . . . . . . . . . . . . . . . . . . . . . 26
3.2. WS-AgreementApplicabilityAnalysis . . . . . . . . . . . . . . . . . . . . . . 27
3.2.1. Participantroles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3.2.2. ProtocolVariants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
3.2.3. ServiceTerms. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
3.3. WSAG4JFrameworkAnalysis . . . . . . . . . . . . . . . . . . . . . . . . . . 30
3.4. RESTasanalternativetoWSRF . . . . . . . . . . . . . . . . . . . . . . . . . 32
3.4.1. HistoryandMotivation . . . . . . . . . . . . . . . . . . . . . . . . . . 34
3.4.2. Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
3.4.3. Interoperability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
3.4.4. NetworkLoadandPerformance . . . . . . . . . . . . . . . . . . . . . 36
3.4.5. RelatedWork . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
3.5. PerformanceEvaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
3.5.1. TestScenarios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
3.5.2. TestInfrastructure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
3.5.3. ImpactofSecurityTechnology . . . . . . . . . . . . . . . . . . . . . . 40
3.5.4. MeasurementResults . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
3.5.5. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
3.6. FurtherREST-basedCloudStandards . . . . . . . . . . . . . . . . . . . . . . 45
3.6.1. CloudApplicationManagementforPlatforms . . . . . . . . . . . . . . 45
3.6.2. CloudInfrastructureManagementInterface . . . . . . . . . . . . . . . 46
3.6.3. OpenCloudComputingInterface . . . . . . . . . . . . . . . . . . . . 47
4. Agreement Mediation Approaches 51
4.1. RegistryApproach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
4.1.1. ServiceVisibilityandDiscovery . . . . . . . . . . . . . . . . . . . . . 54
4.1.2. ComplexityandAutomation . . . . . . . . . . . . . . . . . . . . . . . 55
4.2. BrokerApproach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
4.2.1. AdvertisingSLATemples . . . . . . . . . . . . . . . . . . . . . . . . 56
4.2.2. DiscoveringandComparingserviceoffer . . . . . . . . . . . . . . . . 58
4.2.3. Feedinginmonitoringdata . . . . . . . . . . . . . . . . . . . . . . . . 59
4.2.4. GettingnotifiedaboutSLAevents . . . . . . . . . . . . . . . . . . . . 59
4.3. ESBApproach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
4.3.1. Architecture. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
4.3.2. SLAEngine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
4.3.3. On-BoardingProcess . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
4.3.4. SLAInheritance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
4.4. FederationApproach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
4.4.1. Architecture. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
4.4.2. SLAAggregation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
4.4.3. ExpectedAggregationCount . . . . . . . . . . . . . . . . . . . . . . . 73
4.5. RelatedApproaches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
4.6. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
5. Intercloud SLA Management 79
5.1. XMPP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
5.2. RelatedWork . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
5.3. RESTwithXMPP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
5.3.1. ResourceExploration . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
5.3.2. ResourceAccess . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
5.3.3. ImplementationConcept . . . . . . . . . . . . . . . . . . . . . . . . . 96
5.3.4. PerformanceEvaluation . . . . . . . . . . . . . . . . . . . . . . . . . 100
5.4. RESTwithXMPPRendering . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
5.4.1. ClassificationRendering . . . . . . . . . . . . . . . . . . . . . . . . . 105
5.4.2. RepresentationRendering . . . . . . . . . . . . . . . . . . . . . . . . 108
5.4.3. ImplementationConcept . . . . . . . . . . . . . . . . . . . . . . . . . 109
5.5. IntercloudAgreement-Mediators . . . . . . . . . . . . . . . . . . . . . . . . . 110
5.6. ProtocolExtensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
5.6.1. MonitoringModel . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
5.6.2. ServiceLevelAgreementModel . . . . . . . . . . . . . . . . . . . . . 121
5.6.3. EventProcessingModel . . . . . . . . . . . . . . . . . . . . . . . . . 131
6. Intercloud Prototyping and Evaluation 135
6.1. Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
6.1.1. CommunicationPattern . . . . . . . . . . . . . . . . . . . . . . . . . 138
6.1.2. ServiceDiscovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
6.1.3. ServiceCatalog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
6.1.4. ComplexEventProcessing . . . . . . . . . . . . . . . . . . . . . . . . 142
6.2. Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
6.2.1. UseCaseTesting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
6.2.2. LoadTesting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
6.2.3. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
7. Concluion and Future Work 153
Bibliography 155
A. Appendix 171
A.1. XWADLSchema . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
A.2. REST-XMLSchema . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174
A.3. ClassificationSchema . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
A.4. XML-RenderingSchema . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
A.5. EventLogSchema . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
A.6. EvaluationRecording . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183
Description:negotiations bring better price conditions, customers are often unhappy with negotiated con- tracts .. cally negotiate, renegotiate, create and monitor bi-lateral service level agreements in distributed systems. CloudScale [105], CumuloNumbo [106], GEYSERS [107], Helix Nebula [108], MCN [109],.
