Agile Architecture: Ideals, History, and a New Hope
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This document summarizes Gary Pedretti's presentation on Agile Architecture. It begins by defining architecture and discussing the ideals and principles of Agile Architecture, which come from the Agile Manifesto and ideas from Kent Beck, Martin Fowler, and Scott Ambler. It then discusses common misunderstandings, like thinking Agile means no planning or documentation. This has led to a backlash where some think heavy planning is needed. However, the presentation offers a new hope through tools like CRC cards and sacrificial architectures that align with Agile principles. It emphasizes communication, modeling, and organizational transformation to successfully adopt Agile Architecture.
![BUT FIRST – WHAT IS “ARCHITECTURE”?
“…the highest level concept of a system in its environment. The
architecture of a software system (at a given point in time) is its
organization or structure of significant components interacting
through interfaces, those components being composed of
successively smaller components and interfaces.” – RUP, IEEE
“…shared understanding of the system design…architecture only
includes the components and interfaces that are understood by
all the developers…architecture is a social construct” – Fowler
“Stuff that’s hard [expensive] to change later.” – Neal Ford and
others](https://image.slidesharecdn.com/agilearchitecture-idealshistoryandanewhope-150420094203-conversion-gate02/85/Agile-Architecture-Ideals-History-and-a-New-Hope-4-320.jpg)
Agile Architecture: Ideals, History, and a New Hope
- 1. AGILE ARCHITECTURE – IDEALS, HISTORY, AND A NEW HOPE Gary Pedretti
- 2. GARY PEDRETTI Owner, Sodoto Solutions SODOTO = See One, Do One, Teach One Professional Scrum Trainer, Scrum.org Over sixteen years in the software industry as a generalizing specialist: DBA, coder, BA, architect, tester, manager Scrum: Team member, Scrum Master, PO, Coach GaryPedretti.com @GaryPedretti http://www.linkedin.com/in/GaryPedretti http://www.slideshare.net/earl128 SpeakerRate: http://TinyUrl.com/GarysSpeakerRate
- 4. BUT FIRST – WHAT IS “ARCHITECTURE”? “…the highest level concept of a system in its environment. The architecture of a software system (at a given point in time) is its organization or structure of significant components interacting through interfaces, those components being composed of successively smaller components and interfaces.” – RUP, IEEE “…shared understanding of the system design…architecture only includes the components and interfaces that are understood by all the developers…architecture is a social construct” – Fowler “Stuff that’s hard [expensive] to change later.” – Neal Ford and others
- 5. BUT FIRST – WHAT IS “ARCHITECTURE”? “Architecture is about the important stuff. Whatever that is.” – Fowler
- 6. FRAMEWORK VS. APPLICATION VS. ENTERPRISE Neal Ford describes a “Framework-Level Architecture” – important because the unit of reuse in modern languages is the library or framework Application Architecture = building architecture Enterprise Architecture = city planning Service-Oriented Architecture (SOA) = very interesting as a blend of Application and Enterprise Architectural concerns
- 7. A LONG TIME AGO IN A GALAXY FAR, FAR AWAY… IDEALS AND PRINCIPLES
- 8. LITTLE KNOWN FACTS ABOUT HAN SOLO, THE IDEALIST
- 9. BUDDIES (BASED ON HAN’S PRINCIPLES AND IDEALS)
- 10. AGILE (ARCHITECTURE) HAS IDEALS TOO This is NOT your capital “A” Architects’ architecture!
- 11. AGILE ARCHITECTURE IDEALS, ETC. - SOURCES Ideals, Principles, Ideas => Techniques, Practices, Patterns Agile Manifesto and its Principles Kent Beck, Ward Cunningham, Ron Jeffries, et. al. from eXtreme Programming (XP) Martin Fowler Scott Ambler
- 12. THE MANIFESTO Individuals and interactions over processes and tools Working software over comprehensive documentation Customer collaboration over contract negotiation Responding to change over following a plan That is, while there is value in the items on the right, we value the items on the left more.
- 13. PRINCIPLES BEHIND THE MANIFESTO Welcome changing requirements, even late in development. Agile processes harness change for the customer's competitive advantage. Build projects around motivated individuals. Give them the environment and support they need, and trust them to get the job done. Working software is the primary measure of progress. Continuous attention to technical excellence and good design enhances agility. Simplicity - the art of maximizing the amount of work not done - is essential. The best architectures, requirements, and designs emerge from self- organizing teams
- 14. A WORD ON “EVOLUTIONARY” VS. “EMERGENT” “If you accept the premise that architecture is about things hard to change later, it becomes difficult to allow an architecture to emerge.” – Neal Ford Jeff Sutherland and Rebecca Wirfs-Brock agree Words matter – this is about communication…remember architecture is a social construct…
- 15. XP – KENT BECK’S RULES FOR SIMPLE DESIGN 1. Test Everything (and run all the tests) 2. Eliminate Duplication (code) 3. Express All Ideas (that the author wants to express) 4. Minimize Entities (classes and methods)
- 16. EVOLUTIONARY DESIGN > BDUF No Big Design Up Front (BDUF) Replace with Evolutionary Design Where Evolutionary Design != “code and fix” or Cowboy Hacking
- 17. “ ” OPTIMISM IS AN OCCUPATIONAL HAZARD OF PROGRAMMING, FEEDBACK IS THE TREATMENT. Kent Beck FEEDBACK
- 18. MARTIN FOWLER Famous “Who Needs an Architect?” paper and “Is Design Dead?” blog post Significant emphasis on the untenable split between design and build with software (a technique that can work in engineering, manufacturing, buildings, etc.), with XP practices But in reality, encourages a healthy middle ground – doesn’t disown UML, patterns, design activities, etc. Used Pramod Sadalage’s DB work as an example of the “unchangeable” becoming fluid
- 19. SCOTT AMBLER In his “Agile Modeling,” lays out specific Values Principles Practices Builds off of core agile principles, and forges middle ground regarding UML, patterns, forethought, etc. Worked with Pramod Sadalage on Database Refactoring
- 22. HAN SHOT FIRST!!
- 24. AND SMUG, TOO!!
- 26. BUDDIES REMINDER: BASED ON HAN’S (SELFLESS) PRINCIPLES AND IDEALS
- 27. OH, SO MANY MISUNDERSTANDINGS Agile Principles…
- 28. FIRST, LET’S IMAGINE THE IDEALS ABUSED… XP The Manifesto
- 29. ABUSING XP PRINCIPLES NO BDUF!!! (and skipping the “no Cowboy Hacking, either” part)
- 30. ABUSING THE MANIFESTO NO DOCUMENTATION NECESSARY! NO PLANS! (ignoring the “while there is value in the items on the right” part completely) Individuals and interactions over processes and tools Working software over comprehensive documentation Customer collaboration over contract negotiation Responding to change over following a plan
- 31. ABUSING THE PRINCIPLES BEHIND THE MANIFESTO CODERS ARE GODS NOW – ME ME ME – what’s motivation again? What’s a stakeholder? WORKING SOFTWARE IS THE ONLY THING THAT MATTERS! SIMPLE is best – ALWAYS! Things emerge – I don’t need to think about them!!
- 32. “ ” ONE OF THE MORE INSIDIOUS AND PERSISTENT MYTHS OF AGILE DEVELOPMENT IS THAT UP-FRONT ARCHITECTURE AND DESIGN ARE BAD; THAT YOU SHOULD NEVER SPEND TIME UP FRONT…DESIGN FROM NOTHING, ONE TEST-CASE AT A TIME. PARDON ME, BUT THAT’S HORSE SHIT. “Uncle Bob” Martin WOW!
- 33. HAVE YOU BEEN HERE BEFORE???
- 34. (THE EMPIRE STRIKES BACK?) THE BACKLASH
- 35. GUESS I’M ON MY OWN, HAN…
- 36. CAN YOU BLAME HIM?
- 37. WE’VE SEEN A LOT OF BACKLASH FROM ALL THOSE MISUNDERSTANDINGS… Organizational Snapback New Frameworks to “Address the issue of…” Broken Trust
- 38. ORGANIZATIONAL SNAPBACK – THREE STEPS FORWARD, TWO STEPS BACK “Change Spasm” – Simon Rendl “Organizational Antibodies” – Michael Sahota
- 39. “ ” THERE COMES A POINT AT WHICH EMERGENT DESIGN IS AN INSUFFICIENT RESPONSE TO THE COMPLEXITY OF LARGE-SCALE SYSTEM DEVELOPMENT. From a newer framework Question: Is there a magical point at which waterfall, command/control, phase-gated, heavily plan-based methodologies suddenly just “start to work”?????
- 40. “ ” FOR THIS WE NEED SOME INTENTIONAL ARCHITECTURE—A SET OF PURPOSEFUL, PLANNED ARCHITECTURAL INITIATIVES TO ENHANCE SOLUTION DESIGN, PERFORMANCE AND USABILITY—AND WHICH PROVIDES GUIDANCE FOR INTER-TEAM DESIGN AND IMPLEMENTATION SYNCHRONIZATION. Read: Command and Control?? Funny, Mike Cohn used intentional at least back to 2009… From a newer framework
- 41. “ ” IN THE CASES WHERE NEW PLATFORMS ARE PARTICULARLY INNOVATIVE, OR IN THE CASE OF ENTIRELY NEW (GREENFIELD) DEVELOPMENT, IT IS COMMON THAT SYSTEM ARCHITECTS PLAY A ROLE IN THE INITIAL DEFINITION AND BUILD OUT OF THE RUNWAY. Read: Self-Organizing Teams Probably Can’t Be Trusted From a newer framework
- 42. I HAVE A QUESTION Is there a magical point at which waterfall, command/control, phase-gated, heavily plan-based methodologies suddenly just “start to work”????? But…what about nature?
- 43. CAN PEOPLE BE TRUSTED TO MAKE DECISIONS AT THE LAST RESPONSIBLE MOMENT? Or will they typically conflate responsible with possible? Rebecca Wirfs-Brock said “yes” at Agile 2013 – granted, her blog backs this idea with one psychological study
- 44. “ ” THE PROBLEM IS THAT EMPOWERED TEAMS ARE STILL HUMAN, THEY DO WHAT THEY ARE INCENTED TO DO. ARE THEY BEING REWARDED FOR QUALITY? OR ARE THEY BEING REWARDED FOR PRODUCTIVITY? HOW MUCH RECOGNITION IS THE TEAM GETTING FOR GOOD CODE QUALITY? HOW MUCH ARE THEY GETTING FOR DELIVERING WORKING FEATURES? “Uncle Bob” Martin CAREFUL OF THE INCENTIVES
- 45. CAN YOU BE TRUSTED?
- 46. A NEW HOPE…?
- 48. WE HAVE A NEW HOPE TOO…BACK TO PRINCIPLES
- 49. MISUSE AND ABUSE OF PRINCIPLES I’ve already covered some typical misuses…including where they deviate and what to concentrate on…
- 50. MISUSE AND ABUSE OF PRINCIPLES Let’s look at some other things to get us back to principles…
- 51. TOOLS – FROM THE OBVIOUS TO THE LEAST-EXPECTED
- 52. CRC CARDS AND RESPONSIBILITY- BASED MODELING Play the game with a cross-functional team 1. “Is it really the responsibility of this object to handle this request?” 2. “Is it its responsibility to keep track of all that information?” “The best architectures, requirements, and designs emerge from self-organizing teams.”
- 53. SACRIFICIAL ARCHITECTURES Mike Brittain and Etsy’s Lean Startup experimentation approach: architecture is irrelevant until a feature is proven to be wanted by some pilot demographic, in which case you rebuild it in a sustainable fashion Fowler coined the term “Sacrificial Architecture” in October 2014 to describe these throwaways – “often the best code you can write now is code you'll discard in a couple of years time” Safely enables YAGNI++ “Simplicity - the art of maximizing the amount of work not done - is essential.”
- 54. NON-FUNCTIONAL REQUIREMENTS ARE ACTUALLY FEATURES “Performance is a feature“ – Jeff Atwood What does your product vision actually say about size of market, globalization, user appetite for risk, etc.? Realize any one answer is temporal…it will evolve “Our highest priority is to satisfy the customer through early and continuous delivery of valuable software.”
- 55. UNIFIED MODELING LANGUAGE (UML) AND MODEL-DRIVEN ARCHITECTURE (MDA) “Forward Engineering” – code generation from model “Reverse Engineering” – model extraction from code These approaches enable Ambler’s Agile Modeling Practices of: Single Source of Information Discard Temporary Models Iterate to Another Artifact Prove it with Code Update Only When it Hurts “Deliver working software frequently, from a couple of weeks to a couple of months, with a preference to the shorter timescale.”
- 56. EVEN MORE TOOLS TO DIG INTO
- 57. MENTORSHIP Communities of Practice Lunch and Learns Pairing and Swarming Remember that quote about Architecture fundamentally being a social construct? “Continuous attention to technical excellence and good design enhances agility.”
- 58. COMMUNICATION AND HAVING DIFFICULT CONVERSATIONS “Business people and developers must work together daily throughout the project.”
- 59. “ ” SOFTWARE IS NOT LIMITED BY PHYSICS, LIKE BUILDINGS ARE. IT IS LIMITED BY IMAGINATION, BY DESIGN, BY ORGANIZATION. IN SHORT, IT IS LIMITED BY PROPERTIES OF PEOPLE, NOT BY PROPERTIES OF THE WORLD. “WE HAVE MET THE ENEMY, AND HE IS US. Ralph Johnson YOUR METAPHORS ARE FUNDAMENTALLY BROKEN
- 60. ORGANIZATIONAL TRANSFORMATION “Build projects around motivated individuals. Give them the environment and support they need, and trust them to get the job done.”
- 63. RESOURCES AND CITATIONS Neal Ford http://www.ibm.com/developerworks/java/library/j-eaed1/index.html Martin Fowler http://martinfowler.com/ieeeSoftware/whoNeedsArchitect.pdf http://martinfowler.com/articles/evodb.html http://martinfowler.com/articles/designDead.html Ron Jeffries http://xprogramming.com/xpmag/expEmergentDesign Scott Ambler http://www.agilemodeling.com/practices.htm “Uncle Bob” Martin https://sites.google.com/site/unclebobconsultingllc/home/articles/the-scatology-of-agile- architecture Rebecca Wirfs-Brock http://wirfs-brock.com/blog/2011/05/12/agile-architecture-myths-3-good-architecture- emerges/ http://wirfs-brock.com/blog/2013/08/13/architecture-at-agile-2013/ Mike Cohn http://www.mountaingoatsoftware.com/blog/agile-design-intentional-yet-emergent
Editor's Notes
- #2: Application and Enterprise Architecture has been put through its paces in the agile world over the years: Ideals (architectural work inside the development team, shortening the design-to-implementation loop as much as possible) Misinterpretations and misunderstandings ("We don't need no stinking Architects!" screamed the Keyboard Cowboys) The inevitable backlash of misinterpretations, lack of craft, and the inertia of the status quo (Architectural Epics continuing to encourage a split between business and IT, command-and-control capital-"A" Architects). Where are we now? What have we learned? More importantly, what have we forgotten? Now more than ever, we need to go back to the core principles of agility and emergent architecture. Let's talk.
- #4: This is a tour of Agile Architecture history in rough chronological order, followed by ideas and tools In “A New Hope,” I will talk about specific techniques and mindsets that can help you go forward with success.
- #9: In the Star Wars “expanded universe” of books and comics… Solo loses his commission and is dishonorably discharged when he refuses an order to skin Chewbacca for commandeering a ship carrying Wookiee children destined for slavery; Chewbacca, in turn, swears a "life-debt" to Solo. - Ann C. Crispin's The Han Solo Trilogy (1997–1998)
- #10: Buddies by principle – Chewie’s sworn “life debt” on Han’s principled actions
- #12: Roughly chronological order, going from mid-90s forward
- #20: Values: communication, simplicity, feedback, courage, humility Principles: Assume Simplicity, Embrace Change, Enabling the Next Effort is Your Secondary Goal, Incremental Change, Maximize Stakeholder ROI, Model With a Purpose, Multiple Models, Quality Work, Rapid Feedback, Working Software Is Your Primary Goal, Travel Light Supplementary: Content is More Important Than Representation, Open and Honest Communication Practices: Display Models Publicly, Iterate to Another Artifact (where artifacts are models, diagrams, code, conversations) Active Stakeholder Participation, Apply the Right Artifact(s), Collective Ownership, Create Several Models in Parallel, Create Simple Content, Depict Models Simply, Display Models Publicly, Iterate to Another Artifact, Model in Small Increments, Model With Others, Prove it With Code, Single Source Information, Use the Simplest Tools Supplementary: Apply Modeling Standards, Apply Patterns Gently, Discard Temporary Models, Formalize Contract Models, Update Only When It Hurts
- #26: Greedo was clearly going to hurt Han, looking at the dialogue: HAN: Even I get boarded sometimes. Do you think I had a choice? Han Solo slowly reaches for his gun under the table. GREEDO: You can tell that to Jabba. He may only take your ship. HAN: Over my dead body. GREEDO: That's the idea. I've been looking forward to killing you for a long time. HAN: Yes, I'll bet you have.
- #27: Despite Solo’s swashbuckling, mercenary, out-for-myself appearances, remember that by the time we meet him in Star Wars: A New Hope, he is where he is based on a stand on his principles and ideals Buddies by principle – Chewie’s sworn “life debt” on Han’s principled actions
- #32: Build projects around motivated individuals. Give them the environment and support they need, and trust them to get the job done. – autonomy, mastery, and purpose Working software is the primary measure of progress. Simplicity - the art of maximizing the amount of work not done - is essential. The best architectures, requirements, and designs emerge from self-organizing teams
- #36: Maybe Han is all about the “Solo”?
- #46: Self-Organizing = anarchy, right? NO. Choosing “hows” in contexts of well-defined “whys” and at least partial “whats” Often backlash here when there never was a “why,” nor a will to create one
- #53: Class – Responsibility – Collaborators “Is it really the responsibility of this object to handle this request?” “Is it its responsibility to keep track of all that information?” Play the CRC/RBD game with a cross-functional team!!! This ultimately moves towards DDD, ubiquitous language, strong business/dev relations, etc.
- #56: Star UML, Sparx Enterprise Architect, Argo UML, Borland Together, Visual Studio Ultimate Architecture Tools
- #60: Calls back to the Fowler ideas of fundamental split between manufacturing/design/build and software develpment Speaking of communication… Buildings Engineering Assembly Lines “Architecture” itself!!!