E v o l u t i o n a r y A r c h i t e c t u r e

THE WHYS AND HOWSRebecca Parsons

Chief Technology OfficerThoughtWorks

@rebeccaparsons

WHY SHOULD I CARE?Why should we care?

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We’re good at requirements change.

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What about ecosystem change?

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How is long term planning possible under constant

change?

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How do we maintain this dynamic equilibrium?

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How do we know we’re maintaining our “ilities” over

time?

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WHAT IS EVOLUTIONARY ARCHITECTURE?What is evolutionary architecture?

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An evolutionary architecture supports guided incremental

change across multiple dimensions.

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An evolutionary architecture supports guided incremental

change across multiple dimensions.

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An evolutionary computing fitness function characterizes how close a solution is to the

desired result

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An architectural fitness function characterizes how

close a system is to the desired architectural

characteristics.

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TYPES OF FITNESS FUNCTIONS

▫ Atomic vs holistic▫ Static vs dynamic▫ Triggered vs continuous▫ Manual vs automated▫ Temporal▫ Domain-specific?

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EXAMPLE FITNESS FUNCTIONS

▫ Cyclic dependencies▫ Consumer driven contracts▫ Caching with staleness▫ Monitoring ▫ Synthetic transactions▫ Chaos Monkey

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An evolutionary architecture supports guided incremental

change across multiple dimensions.

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Two aspects of incremental change - application and

operations

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Application functionality

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Incremental from an operations perspective

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An evolutionary architecture supports guided incremental

change across multiple dimensions.

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accessibility reliability repeatabilityaccountability extensibility reproducibility

accuracy failure transparency resilienceadaptability fault-tolerance responsiveness

administrability fidelity reusabilityaffordability flexibility robustness

agility inspectability safetyauditability installability scalabilityautonomy integrity seamlessnessavailability interchangeability self-sustainability

compatibility interoperability serviceabilitycomposability learnability supportabilityconfigurability maintainability securabilitycorrectness manageability simplicitycredibility mobility stability

customizability modifiability standards compliancedebugability modularity survivabilitydegradability operability sustainability

determinability orthogonality tailorabilitydemonstrability portability testabilitydependability precision timelinessdeployability predictability traceability

discoverability process capabilities transparencydistributability producibility ubiquity

durability provability understandabilityeffectiveness recoverability upgradability

efficiency relevance usability

-ilities

PRINCIPLES

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PRINCIPLES OF EVOLUTIONARY ARCHITECTURE

▫ Last responsible moment▫ Architect and develop for evolvability▫ Postels Law▫ Architect for testability▫ Conway’s Law

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Last responsible moment

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Architect and develop for evolvability

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Postel’s Law

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Architect for testability

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Conway’s Law

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TECHNIQUES

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TECHNIQUES OF EVOLUTIONARY ARCHITECTURE

▫ Database refactoring

▫ Choreography

▫ Contract testing

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EVOLVABILITY OF DIFFERENT SOFTWARE ARCHITECTURESEvolvability of different software architectures 32

Big ball of mud

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Structured monolith

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Layered monolith

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Micro-kernel

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Microservices

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MECHANICS

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MECHANICS

▫ Define your architectural fitness function

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MECHANICS

▫ Define your architectural fitness function▫ Select a dimension you’re most worried about

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MECHANICS

▫ Define your architectural fitness function▫ Select a dimension you’re most worried about▫ Start improving on that dimension

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MECHANICS

▫ Define your architectural fitness function▫ Select a dimension you’re most worried about▫ Start improving on that dimension▫ Focus on what matters most

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MECHANICS

▫ Define your architectural fitness function▫ Select a dimension you’re most worried about▫ Start improving on that dimension▫ Focus on what matters most▫ Monitor trends, adapt and repeat

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THANK YOU@rebeccaparsons

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