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 The 25th International Conference on Software Engineering and Knowledge Engineering (SEKE'13) – Boston/MA – USA – June/2013 Architectural Design Spaces for Feedback Control Concerns in Self-Adaptive Systems Sandro S. Andrade and Raimundo J. de A. Macêdo Distributed Systems Laboratory (LaSiD) Department of Computer Science (DCC) Federal University of Bahia (UFBa) - Brazil {sandros, macedo}@ufba.br June/2013 Programa Multiinstitucional de Pós-Graduação em Ciência da Computação
17

Architectural Design Spaces for Feedback Control in Self-Adaptive Systems Concerns

May 11, 2015

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Sandro Andrade

Presented at 25th International Conference on Software Engineering and Knowledge Engineering (SEKE 2013) - Boston/MA - EUA.

A lot of current research efforts in self-adaptive systems community have been dedicated to the explicit modeling of architectural aspects related to system self-awareness and context-awareness. This paper presents a flexible and extensible representation of architectural design spaces for self-adaptation approaches based on feedback control loops. We have defined a generic representation for design spaces meta-modeling and have instantiated it in order to provide direct support for early reasoning and trade-off analysis of self-adaptation aspects with the aid of a set of feedback control metrics. The proposed approach has been fully implemented in a supporting tool and a case study with a distributed industrial data acquisition service has been undertaken. Whilst preliminary experiences with the proposed approach indicate useful reasoning support when comparing alternative design solutions for self-adaptation, further investigation regarding scalability aspects and automatic handling of conflicting goals has been identified as future work.
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Page 1: Architectural Design Spaces for Feedback Control in Self-Adaptive Systems Concerns

   The 25th International Conference on Software Engineering and Knowledge Engineering (SEKE'13) – Boston/MA – USA – June/2013

Architectural Design Spaces for Feedback Control Concerns in Self-Adaptive Systems

Sandro S. Andrade and Raimundo J. de A. Macêdo

Distributed Systems Laboratory (LaSiD)Department of Computer Science (DCC)

Federal University of Bahia (UFBa) - Brazil{sandros, macedo}@ufba.br

June/2013

Programa Multiinstitucional de Pós-Graduação em Ciência da Computação

Page 2: Architectural Design Spaces for Feedback Control in Self-Adaptive Systems Concerns

 The 25th International Conference on Software Engineering and Knowledge Engineering (SEKE'13) – Boston/MA – USA – June/2013

Context & Motivation

Self-AdaptiveSystems

More stringent demandsfor flexibility, dependability,energy-efficiency, ...

Applications thatweigh in at tens of

millions of lines of code

Complexity approachingthe limits of human

capability

Highly unpredictable andchanging operatingenvironments

Page 3: Architectural Design Spaces for Feedback Control in Self-Adaptive Systems Concerns

 The 25th International Conference on Software Engineering and Knowledge Engineering (SEKE'13) – Boston/MA – USA – June/2013

State of the ArtMAPE-K Autonomic Manager(Kephart & Chess; 2003)

3-layer Architecture for Self-Adaptation(Kephart & Chess; 2003)

Middleware-level self-adaptation(e.g.: Rainbow – Garlan et al; 2004)

Explicit Modeling of Control Loops(Hebig, Giese & Becker; 2010)

FORMS Reference Model(Weyns, Malek & Andersson; 2012)

Megamodels@runtime(Vogel & Giese; 2012)

Uncertainty in Self-Adaptive Software Systems(Esfahani & Malek; 2012)

Page 4: Architectural Design Spaces for Feedback Control in Self-Adaptive Systems Concerns

 The 25th International Conference on Software Engineering and Knowledge Engineering (SEKE'13) – Boston/MA – USA – June/2013

Current Challenges

Highly specialized domain andlarge design/solution space

Current effective solutions arehighly tailored to specific problems

Control Theory mechanisms may notdirectly apply in computer systems

Architectural Styles/PatternsReference Architectures

Architecture Design Handbooks

It's hard to support earlyreasoning of properties and

well-informed trade-off analysis

Domain-Specific ADL'sFormal Reference Models/Frameworks

Qualitative Architecture Analysis MethodsQuantitative Architecture Analysis Methods

Model-Based SW Design & DevelopmentSearch-Based Software Engineering

Software Architecture Design Knowledge

Systematic Literature ReviewsModel-Predictive Control

Hybrid Systems Control

Current Approaches

Page 5: Architectural Design Spaces for Feedback Control in Self-Adaptive Systems Concerns

 The 25th International Conference on Software Engineering and Knowledge Engineering (SEKE'13) – Boston/MA – USA – June/2013

Current Challenges

It's hard to support earlyreasoning of properties and

well-informed trade-off analysis

Current effective solutions arehighly tailored to specific problems

Control Theory mechanisms may notdirectly apply in computer systems

Architectural Styles/PatternsReference Architectures

Architecture Design Handbooks

Domain-Specific ADL'sFormal Reference Models/Frameworks

Qualitative Architecture Analysis MethodsQuantitative Architecture Analysis Methods

Model-Based SW Design & DevelopmentSearch-Based Software Engineering

Software Architecture Design Knowledge

Systematic Literature ReviewsModel-Predictive Control

Hybrid Systems Control

Our Approach

Highly specialized domain andlarge design/solution space

Page 6: Architectural Design Spaces for Feedback Control in Self-Adaptive Systems Concerns

 The 25th International Conference on Software Engineering and Knowledge Engineering (SEKE'13) – Boston/MA – USA – June/2013

Our Approach

Systematic representation ofdomain-specific design spaces

DuSE=

+

+

Metrics for evaluation of automaticallygenerated candidate architectures

A multi-objective optimization approachto explicitly elicit design trade-offs

SA:DuSE is a particularDuSE instance whichenables automatedarchitecture design inthe Self-AdaptiveSystems domain

Page 7: Architectural Design Spaces for Feedback Control in Self-Adaptive Systems Concerns

 The 25th International Conference on Software Engineering and Knowledge Engineering (SEKE'13) – Boston/MA – USA – June/2013

Our ApproachAutonomic Manager

KnowledgeMonitor

Analyse Plan

Execute

Managed Element

SA:DuSE provides an automatedprocess for off-line design &analysis of Autonomic Managerarchitectures

Usually designed off-line, butmay be re-designed (adapted)at runtime by the Autonomic Manager

DuSE enables:● Manual design space exploration● Automated search for best candidates (multi-objective optimization)

An initial annotated UMLmodel is provided to SA:DuSE

A lot of degrees of freedom involved:control law, tuning approach, MAPE-K deployment, …

1

2

3

4

5

Page 8: Architectural Design Spaces for Feedback Control in Self-Adaptive Systems Concerns

 The 25th International Conference on Software Engineering and Knowledge Engineering (SEKE'13) – Boston/MA – USA – June/2013

DuSE Metamodel

Page 9: Architectural Design Spaces for Feedback Control in Self-Adaptive Systems Concerns

 The 25th International Conference on Software Engineering and Knowledge Engineering (SEKE'13) – Boston/MA – USA – June/2013

SA:DuSE Design SpaceVP11: ProportionalVP12: Proportional-IntegralVP13: Proportional-Integral-DerivativeVP14: Static State FeedbackVP15: Precompensated Static State FeedbackVP16: Dynamic State Feedback

DD1: Control Law

VP31: Fixed Gain (no adaptation)VP32: Gain SchedulingVP33: Model Identification Adaptation Control

DD3: Control Adaptation

VP21: Chien-Hrones-Reswick, 0 OS, Dist. RejectionVP22: Chien-Hrones-Reswick, 0 OS, Ref. TrackingVP23: Chien-Hrones-Reswick, 20 OS, Dist. RejectionVP24: Chien-Hrones-Reswick, 20 OS, Ref. TrackingVP25: Ziegler-NicholsVP26: Cohen-CoonVP27: Linear Quadratic Regulator

DD2: Tuning Approach

VP41: Global ControlVP42: Local Control + Shared ReferenceVP43: Local Control + Shared Error

DD4: MAPE Deployment

Page 10: Architectural Design Spaces for Feedback Control in Self-Adaptive Systems Concerns

 The 25th International Conference on Software Engineering and Knowledge Engineering (SEKE'13) – Boston/MA – USA – June/2013

SA:DuSE Quality Metrics

M2: Average

Settling Time

ME2=allOwnedElements ()→ selectAsType(QParametricController )→sum(stime())

allOwnedElements()→selectAsType(QParametricController )→size ()

; where QParametricController : : stime()=−4

log(maxi∣p i∣);and max i∣pi∣is themagnitude of thelargest closed−loop pole

M1: Control

Overhead

ME1=allOwnedElements ()→ selectAsType (QController )→ collect(overhead ())→sum ()

allOwnedElements ( )→selectAsType (QController )→size()

;QController : : overhead( )increasingly penalizes VP32, VP33, VP41and VP43

M4: Control

Robustness

ME4=allOwnedElements ()→ selectAsType(QController )→collect (robustness())→sum ()

allOwnedElements()→selectAsType(QController )→size()

;QController : :robustness()increasingly penalizesVP31 andVP32

M3: Average

Maximum Overshoot

ME3=allOwnedElements()→selectAsType(QParametricController)→sum (maxOS ())

allOwnedElements()→selectAsType(QParametricController )→size ()

; where QParametricController : : maxOS ()={0 ;real dominant pole p1≥0

∣p1∣;real dominant pole p1<0

r π/∣θ∣;dominant poles p1, p2=r.e±j. θ}

Page 11: Architectural Design Spaces for Feedback Control in Self-Adaptive Systems Concerns

 The 25th International Conference on Software Engineering and Knowledge Engineering (SEKE'13) – Boston/MA – USA – June/2013

The DuSE Optimization ApproachA simple initial model with three loci of decision yields 54,010,152 candidates

With four loci of decision we get a space with 20,415,837,000 candidates

A search-based approach enables effective design space explorationand helps prevent false intuition and technology bias. The goal is to find

out a set of (locally) Pareto-optimal candidate architectures

Page 12: Architectural Design Spaces for Feedback Control in Self-Adaptive Systems Concerns

 The 25th International Conference on Software Engineering and Knowledge Engineering (SEKE'13) – Boston/MA – USA – June/2013

Case Study

Cloud-based mediaencoding service

Three loci of decision(controllable components)

Annotations from Qemu +Hadoop + CloudStackexperiments

Control goal: enforceencoding throughput

Page 13: Architectural Design Spaces for Feedback Control in Self-Adaptive Systems Concerns

 The 25th International Conference on Software Engineering and Knowledge Engineering (SEKE'13) – Boston/MA – USA – June/2013

Findings

Major trade-off betweenM

2 and M

3, but also M

2

and M4

M2/M

3 Pareto front:

● PI+CHR-20OS-DR● PID+CHR-0OS-DR● P+ZN

Page 14: Architectural Design Spaces for Feedback Control in Self-Adaptive Systems Concerns

 The 25th International Conference on Software Engineering and Knowledge Engineering (SEKE'13) – Boston/MA – USA – June/2013

Related Work

Automated Architecture Improvementfor Performance and other Attributes(Koziolek & Reussner; 2011)

Search-Based Software Architecture Design

A Meta-Framework for Design SpaceExploration(Saxena & Karsai; 2011)

+ Effective representation of architecture design knowledge- Limited extension to specific application domains

Explicit Modeling of Control Loops(Hebig, Giese & Becker; 2010)

FORMS Reference Model(Weyns, Malek & Andersson; 2012)

Megamodels@runtime(Vogel & Giese; 2012)

Actor-Based Adaptable Loops(Krikava et al; 2012)

Multiple Objective Self-Adaptation(Cheng, Garlan & Schmerl; 2006)

Software Engineering for Self-Adaptive Systems

+ Expressive constructs to model self- Adaptive aspects- No systematic knowledge representation- Low parsimony / No trade-off elicitation SA:DuSE

Page 15: Architectural Design Spaces for Feedback Control in Self-Adaptive Systems Concerns

 The 25th International Conference on Software Engineering and Knowledge Engineering (SEKE'13) – Boston/MA – USA – June/2013

Conclusion and Future Work

Limitations Requires an initial annotated architectural model

No guaranteed optimality (local-optimal Pareto fronts)

Still requires a posteriori preference articulation

Contributions Systematic gathering of architecture designknowledge in the field of Self-Adaptive Systems

A search-based approach for endowing architectureswith self-adaptative behaviour and explicit support

for well-informed design trade-off analysis

A supporting tool (DuSE-MT)

Current & Future Work Second case study

Resulting Parent front evaluation (indicators)

From Design Spaces to Design Theories

Page 16: Architectural Design Spaces for Feedback Control in Self-Adaptive Systems Concerns

 The 25th International Conference on Software Engineering and Knowledge Engineering (SEKE'13) – Boston/MA – USA – June/2013

DuSE-MT

Page 17: Architectural Design Spaces for Feedback Control in Self-Adaptive Systems Concerns

   The 25th International Conference on Software Engineering and Knowledge Engineering (SEKE'13) – Boston/MA – USA – June/2013

Thank you !Questions ?

Sandro S. Andrade and Raimundo J. de A. Macêdo

Distributed Systems Laboratory (LaSiD)Department of Computer Science (DCC)

Federal University of Bahia (UFBa) - Brazil{sandros, macedo}@ufba.br

June/2013

Programa Multiinstitucional de Pós-Graduação em Ciência da Computação