SARA: A tool for service levels aware contracts

Transcription

1 Universita del Salento Database and Information systems lab SARA: A tool for service levels aware contracts Prof. M. Bochicchio, Prof.ssa Antonella Longo, Ing. S. Giacovelli

2 Contents The scenario SARA: tool description Conclusions and future works 2

3 THE SCENARIO Provider VM or VWS Company B ecatalogue epayments Bank Company A eshop Client

4 THE SCENARIO Provider VM or VWS Company B ecatalogue epayments Bank Company A eshop Client

5 THE SCENARIO Provider VM or VWS Company B ecatalogue epayments Bank Company A eshop Client

6 PROBLEMDEFINITION Contract Managementand Composition in a Service-Oriented perspective Contract Management Process of systematically and efficiently managing contract creation, execution, and analysis aimed at maximizing performance and minimizing risks Service Level Agreement It includes description of parties, services, service levels specifications, and customer and provider obligations Service Level Management Process of managing 6 performance provided to the customer by optimizing tradeoff between costs and quality of services 6

7 PROBLEM DEFINITION Contract Management for IT Services Contract Management SLA Service Level Management Resources Management SLAis the glue between contracts, service levels and enterprise resources: it is, a portion of the contract, defines and regulates service levels, and is based on enterprise resources. 4

8 PROBLEM DEFINITION Contract Managementand Compositionin a Service-Oriented perspective Service Composition Contracts Composition Services Contracts Relations The process of derivation of a contract, obtained from the composition of other contracts, signed with different providers 7

9 RESEARCH QUESTIONS In contract composition we notice a lack of tools aided to support who must guarantee service levels. Given a service chain governed by several contracts, our purpose is to answer the following questions: Can an IT manager guarantee a certain service level to the final user? Given a number of contracts and related SLAs, what target can be guaranteed to the final users? What impact has the variation of a certain contract on the service level guaranteed to the finale user? What service level target has IT manager to negotiate with providers in order to guarantee a predefined service level? How service contracts are related to enterprise resources (i.e. human resources, IT resources, etc.) and IT service chains? 9

10 STATE OF THEART Models: - Contract Management process representation - Cloud services monitoring - Requirements specifications for SLA Frameworks: - Mode4SLA for services dependencies analysis - WSLA for SLs definition and monitoring -Cremona for services provision management through SLAs Contracts Specification Languages:WSOL, SLAng, WS-Agreement and WS-Negotiation 10 9

11 STATE OF THEART INDUSTRIALTOOLS Traditional Contract Management Tools Obligation Management Tools Resources Representation Tools Service-oriented Contract Management Tools 10

12 THE CHECK POINT MODEL(1/2) It is a method to measure and control IT multiple contracts dependencies in SLAs, based on real world scenarios, i.e. when multiple providers are accountable for interdependent services on one or more service chains. It is a descriptive model based on network diagrams, easily understandle by IT and business skill A service chain is a pool of network and services, which are combined to deliver a service to a final user. 12

13 THE CHECK POINT MODEL(2/2) A check point is a contractual border on the technical graph Name Description SLA specification Provider Service Level Indicatos(1 n) Formula Worikingperiod (i.e. the temporal window of observation) Tracking period (i.e. the temporal window for the SLA calculation) 13

14 SARA: A SERVICE-ORIENTED CONTRACTMANAGEMENT To design and implement a tool to generate dynamic resources representation and handle contracts mapping on services and resources with the following goals: to automatically generate diagrams from a data source; to allow the definition of different level of details for complex diagrams; to allow the user to save into the database changes made to the diagram; to represent the mapping between contracts, services and resources. 5

15 SARA:A SERVICE-ORIENTED CONTRACT MANAGEMENT Functionalities Contract Management Contractmappingon services and resources Syntactic Analysis Service Levels evaluation on check points Contract Composition Composition rules Feasibility Validation (parameters compliance) Result evaluation 11

16 SARA: REQUIREMENTSANALYSIS USERS FUNCTIONALITIES: 1. CONTRACTS MAPPING ON SERVICES AND RESOURCES 2. CONTRACTS COMPOSITION REPRESENTATION 3. SERVICE GRAPH REPRESENTATION 4. DETAILS VISUALIZATION AND 16 MODIFICATION 12

17 DATABASEMODELING RESOURCES 13

18 DATABASEMODELING CONTRACTS 18 Contract Information Service Levels 14

19 SOFTWARE, LANGUAGES AND LIBRARIES Software: Microsoft Visio as graphical environment Microsoft Access asdatabasemanagement System Languages: Visual Basic for Application(VBA) Structured Query Language(SQL) Libraries: Data Access Objecttohandleoperationson data sources with VBA 19 21

20 EVALUATION Apart from the usual usability guidelines, we validated the tool according to some principles for designing effective visual notations [5]: The principle of semiotic clarity is accomplished by the tool, as there is only one graphical structure corresponding to each semantic concept and vice versa. The principle of perceptual discriminability is taken into account to differentiate between refinements, having each kind of refinement a clearly distinct shape The principle of dual coding: we used text with the name to complement the graphics The principle of graphic economy: the number of different graphical symbols in the model is under the upper limit of six categories for graphics complexity The principle of complexity management is covered by the cluster functionality in the tool. The principle of cognitive integration: modules are combined by having the same box appearing in several diagrams [5] D. L. Moody. The Physics of Notations: Toward a ScientificBasis for Constructing Visual Notations in Software Engineering. IEEE Transactions on Software Engineering, 35(6): ,

21 CONCLUSIONS SARA ispart ofthe approachweare developingforservice- Oriented Contract Management Sara aims at helping managers to tame the complexity of IT scenarios and to understand the relationships between IT service architecture, contracting and (reachable) SLAs target objectives. Check points models are supported with primitives and macros. Graphical visualization of service and contract composition is derived by data stored in databases or CMDB. The link between the systems for managing resources and contracts terms and conditions improves service levels and helps in shaping clearer contracts. 23

22 Porting the tool on the Web FUTURE WORKS Adding models and features also to manage contract s administrative aspects. 22

23 THANK YOU FOR YOUR ATTENTION! 24

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