PhD Student E&CE Department University of Waterloo Spring 2005

Transcription

1 Dynamic Adaptation CBSS Course Presentation Instructor: Dr. Ladan Tahvildari Provided by: Mazeiar Salehie PhD Student E&CE Department University of Waterloo Spring 2005 References Main references M. Sadjadi, P. McKinley and B. Cheng, Transparent Shaping of Existing Software to Support Pervasive and Autonomic Computing, In proc. of DEAS workshop, USA, 2005 McKinley, P. K., Sadjadi, S. M., Kasten, E. P., and Cheng, B. H Composing Adaptive Software. Computer 37, 7 (Jul. 2004), pp Philip K. McKinley, S. Masoud Sadjadi, Eric P. Kasten, and Betty H. C. Cheng. A taxonomy of compositional adaptation. Technical Report MSU-CSE-04-17, Department of Computer Science, Michigan State University, May S. M. Sadjadi, P. K. McKinley, R. E. K. Stirewalt, and B. H.C. Cheng. TRAP: Transparent reflective aspect programming. Technical Report MSU-CSE-03-31, Computer Science and Engineering, Michigan State University, Michigan, November S. M. Sadjadi and P. K. McKinley. ACT: An adaptive CORBA template to support unanticipated adaptation. Technical Report MSU-CSE-03-22, Department of Computer Science, Michigan State University, Michigan, August Further reading M. Aksit and Z. Choukair, Dynamic, Adaptive, and Reconfigurable Systems Overview and Prospective Vision, Proc. 23rd Int l Conf. Distributed Computing Systems Workshops (ICDCSW03), IEEE CS Press, May 2003, pp Maes, P. Concepts and experiments in computational reflection. In OOPSLA '87, USA, (Oct. 1987). Schmidt, D. C Middleware for real-time and embedded systems. Communication of ACM 45, 6 (Jun. 2002) S. M. Sadjadi and P. K. McKinley. Transparent self-optimization in existing CORBA applications. In Proceedings of the International Conference on Autonomic Computing (ICAC-04), pages 88-95, New York, NY, May S. Masoud Sadjadi and P. K. McKinley. Using transparent shaping and web services to support selfmanagement of composite systems. In Proceedings of the International Conference on Autonomic Computing (ICAC'05), Seattle, Washington, June S. M. Sadjadi, P. K. McKinley, and E. P. Kasten. MetaSockets: Run-time support for adaptive communication services. Technical Report MSU-CSE-02-22, Department of Computer Science, Michigan State University, East Lansing, Michigan, July Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 2

2 Outline Introduction Definition General Approaches Enabling Technologies Compositional Adaptation Where How When Sample Tools TRAP ACT Research Challenges Conclusion Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 3 Introduction Definition: A software application is adaptable if it can change its behavior dynamically (at run time) in response to transient changes in its execution environment or to permanent changes in its requirements. Two major drivers: Pervasive/Ubiquitous Computing: changing environments Autonomic Computing: self-managing systems Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 4

3 General Approaches Two general approaches have been used to realize dynamic adaptation: Parameter Adaptation Compositional Adaptation Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 5 Parameter Adaptation Parameter adaptation involves the modification of variables that determine program behavior. M. A. Hiltunen and R. D. Schlichting, Adaptive distributed and fault-tolerant systems, International Journal of Computer Systems Science and Engineering, vol. 11, pp , September A weakness of parameter adaptation is that it cannot adopt algorithms or components left unimplemented during the original design and construction of an application. Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 6

4 Compositional Adaptation Compositional adaptation results in the exchange of algorithmic or structural parts of the system with ones that improve a program s fit to its current environment. P. K. McKinley, U. I. Padmanabhan, N. Ancha, and S. M. Sadjadi, Composable proxy services to support collaboration on the mobile internet, IEEE Transactions on Computers (Special Issue on Wireless Internet), pp , June W.-K. Chen, M. A. Hiltunen, and R. D. Schlichting, Constructing adaptive software in distributed systems, in Proceedings of the 21st International Conference on Distributed Computing Systems (ICDCS-21), (Mesa, Arizona), pp , April In comparison to parameter adaptation, compositional adaptation enables an application to adopt new algorithms/components for addressing concerns unforeseen during original design and construction. Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 7 Outline Introduction Definition General Approaches Enabling Technologies Compositional Adaptation Where How When Sample Tools TRAP ACT Research Challenges Conclusion Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 8

5 Enabling Technologies Component-Based Design Compositional Adaptation Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 9 Component-Based Design Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 10

6 Enabling Technologies Separation of Concerns Component-based Design Compositional Adaptation Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 11 Separation of Concerns Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 12

7 Enabling Technologies Separation of Concerns Computational Reflection Component-based Design Compositional Adaptation Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 13 Behavioral Reflection Maes, P. Concepts and experiments in computational reflection. In OOPSLA '87, USA, (Oct. 1987). Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 14

8 Enabling Technologies Separation of Concerns Computational Reflection Component-based Design Compositional Adaptation Middleware Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 15 Middleware Schmidt, D. C Middleware for real-time and embedded systems. Communication of ACM 45, 6 (Jun. 2002) Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 16

9 Outline Introduction Definition General Approaches Enabling Technologies Compositional Adaptation Where How When Sample Tools TRAP ACT Research Challenges Conclusion Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 17 Where to Compose Client Program Server Program Application Layer Requester Component Interaction Provider Component Middleware Layer Operating System Network process boundaries Program component Flow of service request Hook A typical client/server application. Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 18

10 Where to Compose (2) Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 19 How to Compose Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 20

11 How to Compose (2) The role of composer Transparency: Is an application aware of the infrastructure needed for re-composition? Transparent shaping: supports the design and development of adaptable programs from existing programs without the need to modify the existing programs source code. Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 21 When to Compose Tunable software: prohibits modification of code for the business logic, only supports fine-tuning of cross-cutting concerns. Composition Type Mutable Tunable Configurable Customizable Hardwired Transparent Shaping Dynamic Static Develop. Time Compile Time Startup Time Run Time Time Hardwired Middleware: Electra, Totem, Horus, Isis Customizable Middleware: Personal/Embedded Java, Orbix/E Configurable Middleware: Eternal, IRL, FTS, TAO-LB, Rocks, Racks, Orbix, ORBacus, JacORB, QuO Tunable Middleware: TAO, ZEN, CIAO, DynamicTAO, UIC, OpenCORBA, ACE, FlexiNet, Iguana/J, MetaXa Mutable Middleware: Open ORB, Open COM Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 22

12 Dynamic Adaptation Phases Producing an adapt-ready program a program whose behavior can be adapted at run-time by insertion or removal of adaptive code (interceptor or hook ) at sensitive JoinPoints Run-time adaptation in which the composer switches the hook at sensitive joinpoints from original to alternative hooks. X 1 (adapt-ready program) X 0 (existing program) X 2 (adapt-ready program) First Step: at compile, startup, or load time X 3 X 4 X 5 X 6 X 7 Second Step: at run time X 8 S 1 S 2 X 9 X working program design decision reversible design decision subfamily boundary Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 23 Outline Introduction Definition General Approaches Enabling Technologies Compositional Adaptation Where How When Sample Tools TRAP ACT Research Challenges Conclusion Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 24

13 Sample Tools (1): Transparent Reflective Aspect Programming (TRAP) Original Application (.class files) A configuration file (contains a list of classes to become reflective) Existing program Selecting classes Generating hooks Weaving hooks TRAP/J at Compile Time Intercepting Aspect Generator Reflective Class Generator Intercepting Wrapper-Level MetaLevel Meta-Level BaseLevel Aspect Aspects Class Class Class Class AspectJ Compiler (ajc) Generated adapt-ready application (.class files) Data Flow A File A Process TRAP/J Boundary Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 25 Case study: Wireless Audio Streaming FEC stands for Forward Error Correction Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 26

14 Sample Tools (2): Adaptive CORBA Template (ACT) ACT uses CORBA portable interceptor, which can be incorporated into a CORBA program at startup time using a command-line parameter. Later at run-time, these hooks can be used to insert adaptive code into the adaptready program. Client Program Server Program Application Layer Middleware Layer Requester object ACT Core Generic Interceptor Client ORB Provider object ACT Core Generic Interceptor Server ORB Operating System Network process boundaries Program component Request flow Request flow Hook Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 27 Transparent Shaping Contributions & Artifacts Model... Transparent Shaping Programming Model Extensions.. TRAP ACT Prototypes... TRAP/J ACT/J Hooks. Wrappers & Metaobjects Generic Interceptors Core Assets adaptive code Coarse-Grained.. Fine-Grained Delegates: MetaSockets Filters: FEC, Encryption/Dec., Compression/Dec. Proxies: Generic Proxy Rules: Conn. Management,App. Integration Existing Applications... Audio Streaming App. Image Retrieval App. Frame Grabber App. Crosscutting Concerns.. QoS Security QoS vs. Energy Man. Self-Management/Optimization App. Integration instantiates provides uses is applied to supports Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 28

15 Relationships with other Contributions Adaptable Applications, Existing/Non-Adaptable Applications Application TRAP/J, Composition Filters, RNTL ARCAD, BBS, Domain-Specific Services Transparent Shaping QuO, OGS, ACT/J, IRL,FTS,TAO-LB, Java RMI, TAO,DynamicTAO,Orbix, JacORB, Squirrel,OpenCorba, OpenORB, Electra, Iguana/J, PROSE, Guaraná, MetaSockets, Java Net Package, ACE, Horus, Isis, Ensemble, Common Services Distribution Services Host-Infrastructure Services Middleware KMX, Eternal, Rocks, Racks, DEOS, GRACE, Graybox, Windows OS, Linux OS, Sun Solaris OS, Mac OS System Platform Transparent shaping boundary Hooks to incorporate adaptive code dynamically Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 29 Research Challenges Assurance Techniques are needed to ensure that the system still executes in an acceptable or safe manner during/after the adaptation process Certify all components for correctness with respect to their specification Security Hiding adaptation management from would-be intruders and prevent them from impeding or corrupting the adaptation process. Interoperability Tools and methods to integrate the operation of adaptive components across the layers of a single system, among multiple systems, and between different adaptive frameworks. Decision making Deciding how, when and where to adapt the system (by composer) Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 30

16 Conclusion Dynamic Adaptation (according to Aksit et al.) is a special case of self-configuring The focus is on realizing the idea of system families and variations at run-time Compositional Adaptation (Transparent Shaping) Separation of Concerns Component-Based Design Computational Reflection middleware There is no reference to dynamic architecture and ADLs There is no details on how and by which mechanism a composer can decide about the dynamic composition Using rule-based, policy-based, machine learning approaches or control theory similar to autonomic computing Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 31 Dynamic Adaptation CBSS Course Presentation Mazeiar Salehie PhD Student E&CE Department

17 Support Slides Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 33 TRAP Layered Run-time Model Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 34

18 TRAP/J Trap/J run-time support A simplified run-time class graph. Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 35 TRAP & ACT Rule-Based Interceptor rule dynamic interceptor generic interceptor MetaSocket filter pipeline pipeline delegate meta object read readsmall stub send close CORBA ORB send_request Generic Interceptor Java Socket Class InvokeMethod RemoveInterceptor InsertInterceptor GetStatus RemoveDelegate InsertDelegate GetStatus Image Client Interaction Network Image Server Application Layer Middleware Layer Operating System process boundaries Program object Flow of service request Hook ASA Sender Interaction Ad Hoc Network process boundaries ASA Receiver Application Layer Middleware Layer Operating System wrapper object WrapperLevel_Socket Program object Flow of service request Hook Thursday, July 21, 2005 Mazeiar Salehie, E&CE Dept., UWaterloo 36

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