QoS Contract Preservation through Dynamic Reconfiguration: A Formal Semantics Approach

Transcription

1 QoS Contract Preservation through Dynamic Reconfiguration: A Formal Semantics Approach Gabriel Tamura, Rubby Casallas, Anthony Cleve, Laurence Duchien 1

2 QoS Contract Preservation through Dynamic Reconfiguration : a Formal Semantics Approach 2

3 The Quest for Quality-of- Service in Software Services Software Services:! In everyday life! Massively accessed! Users increasingly depend on them... but also require increasing quality of service guarantees! QoS Software Contracts 3

4 4 Quality-of-Service Challenges in SaaS - Cloud Computing

5 A QoS Contract Example Challenges for Computing Infrastructures (e.g., IBM Websphere, Movistar, Tuboleta.com) Context Condition QoS Service Level Regular Days 100 T / min Thanksgiving Day 400 T / min Christmas Eve 900 T / min...? 5

6 Annual Uptime 99.95% (based on cumulative RUs) Context Condition Periods of 5 minutes («Region Unavailable» state) along a Year Outside the «Region Unavailable» state QoS Service Level No guarantees 100% Availability 6

7 QoS Contract Preservation Must be Reliable Amazon s Elastic Cloud Computing Crash Raises Reliability Questions Surrounding the Cloud, April 2011* Amazon.com, the world s largest online retailer Internet-based computing services, used by thousands of business customers to run their Web pages and store data, crashed this morning and knocked sites across the U.S. Offline: Netflix, Elli Lilly, Salesforce.com, Bestbuy, and others... bringing down a handful of well known websites. Amazon refunds you 10% of the bill on your next invoice, in case of contract unfulfillment * 7

8 8

9 9

10 Overview QoS-CARE: A Comprehensive Solution to Preserve QoS Contracts Reliably at Run-time n From a formal foundation n... to a concrete software architecture and implementation n and its validation: Theoretically, on the formal model properties to guarantee its reliability Experimentally, on its practical feasibility 10

11 11

12 12

13 13

14 14

15 15

16 16

17 17

18 18

19 19

20 20

21 21

22 22

23 23

24 24

25 25

26 26

27 27

28 28

29 29

30 30

31 31

32 32

33 33

34 34

35 35

36 36

37 37

38 38

39 39

40 40

41 41

42 42

43 43

44 44

45 45

46 46

47 Thank You! 47

48 Publications International Journals u Gabriel Tamura; Rubby Casallas; Anthony Cleve; Laurence Duchien. QoS Contract Preservation through Dynamic Reconfiguration: A Formal Semantics Approach, Science of Computer Programming, 94(3): , Elsevier, Book chapters n n n Gabriel Tamura, Norha M. Villegas, Hausi A. Müller, João P. Sousa, Basil Becker, Mauro Pezzè, Gabor Karsai, Serge Mankovskii, Wilhelm Schäfer, Ladan Tahvildari, and Kenny Wong. Towards Practical Runtime Verification and Validation of Self-Adaptive Software Systems. In: Software Engineering for Self-Adaptive Systems 2, LNCS Vol Norha M. Villegas, Gabriel Tamura, Hausi A. Müller, Laurence Duchien, and Rubby Casallas. DYNAMICO: A Reference Model for Governing Control Objectives and Context Relevance in Self-Adaptive Software Systems. In: Software Engineering for Self-Adaptive Systems 2,, LNCS Vol Rogerio de Lemos, Holger Giese, Hausi Müller, Mary Shaw, Jesper Andersson, Luciano Baresi, Basil Becker, Nelly Bencomo, Yuriy Brun, Bojan Cukic, Ron Desmarais, Schahram Dustdar, Gregor Engels, Kurt Geihs, Gabriel Tamura, et al. Software Engineering for Self-Adaptive Systems: A Second Research Roadmap. In: Software Engineering for Self- Adaptive Systems 2, LNCS Vol International Symposiums n Norha Villegas, Hausi Müller, Gabriel Tamura, Laurence Duchien, and Rubby Casallas. A Framework for Evaluating Quality-Driven Self-Adaptive Software Systems. Procs. of 6 th Intl. Symposium on Software Engineering for Adaptive and Self-Managing Systems, International Workshops n Thesis n Gabriel Tamura, Rubby Casallas, Anthony Cleve, and Laurence Duchien. QoS Contract-Aware Reconfiguration of Component Architectures Using E-Graphs. Procs. of 7th Intl. Workshop on Formal Aspects of Component Software, Selected also for publication on the LNCS Vol Formal Aspects of Component Software Gabriel Tamura QoS-CARE: A Reliable System for Preserving QoS Contracts through Dynamic Reconfiguration, Ph.D. dissertation, University of Lille 1 - Science and Technology, and Universidad de Los Andes,