Integrating WS-Agreement with a Framework for Service- Oriented Infrastructures

Transcription

1 Integrating WS-Agreement with a Framework for Service- Oriented Infrastructures Run WS-Agreement services within the SLA@SOI Framework Date: 26/10/2010 Speaker: Peter Chronz, Philipp Wieder Organisation: TU Dortmund, Service Computing Group

2 Outline What offers Why syntax conversion? Methodological approach: The SLA* model Technical approach: A generic SLA manager Conversion example Open issues 2

3 Project Objectives & Solutions SLA management framework Harmonizing perspectives of relevant stakeholders (software/service/ infrastructure provider and customer) General methods for SLA specification and negotiation & systematic multilayer SLA management (planning, optimization, and provisioning), monitoring and accounting Adaptive SLA-aware infrastructures Well defined interfaces for adaptive infrastructures with harmonized access to different virtualization technologies. Advanced technologies for SLA enforcement on infrastructure level Engineering methods for predictable service-oriented systems Modelling techniques and prediction tools for SOA and SOI components Business management suite for e-contracting Covers complete business lifecycle of a service provisioning and delivery 3

4 The Framework Customer Service Provider Business Use Procurement Service Demand Business Assessment SLA (Re-)Negotiation Monitoring, Arbitration SLA Business Assessment SLA Orchestration/ Transformation/ Aggregation Contracting/ Sales SOA Monitoring Adjustment Alerting Service Demand Forecasting Software Provider Infrastructure Provider Provisioning Resource Consumption Forecasting virtual Mapping SOI physical 4

5 Reference Architecture framework core Customer <<customer_relations>> Business Manager <<provider_relations>> 3 rd Party <<negotiate>> Business SLA Manager <<control/track>> <<negotiate>> Software SLA Manager <<evaluate>> Service Evaluation <<prepare/ manage>> Infrastructure SLA Manager <<prepare/manage>> Software Service Manager Monitored Event Channel Infrastructure Service Manager deployed software service Manageability Agent <<adjust>> Software Service <<publish>> 5 Manageability Agent <<adjust>> Infrastructure Service deployed infrastructure service

6 An Application Scenario 6

7 Motivation for Syntax-Conversion Various types of renderings s SLA model allows various types of renderings XML RDF/OWL JSON Framework internal representation is Java Essential: Conversion between string-based representations and Java-based representations Various types of SLA models supports various types of SLAs Its own SLA model WS-Agreement with embedded content Potentially further models Framework internal model is SLA* required: Conversion between different SLA models 7

8 The Basis: s SLA Model Provides various representations XML, JSON, Java Uses vocabularies as extensions to the core model Business Terms Infrastructure Terms QoS Terms Validates content automatically Makes use of external vocabulary Validation included e.g. is the data-type right? Is the value in the predefined range? Has been developed based on WS-Agreement extensions Domain-specific extensions for certain domains targetting e.g. the infrastructure layer 8

9 Generic SLA Manager Syntax Converter Protocol Engine SLA Registry Provisioning And Adjustment Monitoring Manager SLA Template Registry Planning And Optimization 9

10 Syntax-Conversion in Action 10

11 Approach Ideal versus pragmatic Pragmatic approach has been chosen to ease the implementation Potential problems Semantics of mapping may not be clear directly Documentation essential for programmers/adopters Bi-lateral mapping necessary Realise domain-specific WS-Agreement extensions as SLA* elements SLA* provides in general simple solutions E.g. XPath for XML-based systems versus SLA* PATH 11

12 Example Mapping WS-Agreement ß à SLA* Top-level Name SLA identifier wsag:guaranteeterm to slasoi:guaranteed Obligated Precondition of a guaranteed state or action QualifyingCondition Also goes into the precondition of state/action ServiceLevelObjective Guaranteed state BusinessValueList No explicit support in SLA@SOI BusinessValueList to SLA* Penaltys/Rewards E.g. custom guaranteed action with AssessmentInterval and Count as precondition 12

13 Selected Conversion Issues Constraint expressions WS-Agreement uses XML-Schema-based constraints s model has its own constraint concept WS-Agreement constraints cannot be mapped to SLA* constraints in all cases Using as free-formed constraints in WS-Agreement is one solution (but then standard validation does not work) Business terms Only supported by via an external vocabulary Not included in core model Many minor issues Missing elements and attributes in need to be supported by complementary vocabularies Such extensions are foreseen in 13

14 Thank you! 14

15 Colour Scheme Main colours (according to branding scheme) R(255) R(0) R(150) R(0) G(255) G(0) G(150) G(153) B(255) B(0) B(150) B(255) R(0) R(103) R(221) R(77) G(51) G(204) G(221) G(77) B(102) B(255) B(221) B(77) Additional colours (to be used for fancy diagrams) R(204) R(255) R(255) R(255) G(204) G(255) G(204) G(153) B(255) B(153) B(153) B(102) R(204) G(255) B(204) 15