Applying Agile Values to Enterprise Architecture

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Applying Agile Values to Enterprise Architecture

Software Architectural Trends
Past, Present, and Onwards

by: Benjamin Scherrey

Chief Systems ArchitectProteus Technologies, Co. Ltd.

Twitter: @proteusguyEmail: scherrey@proteus-tech.comhttp://proteus-tech.com

Architecture

Architecture is Form not Structure

Keeps the effort focused on Value

Identifies the Stable Parts of the System

Introduces Constraints (Architectural Drivers)

The result of tough decisions made now in order to make future decisions easier

Debate: Does Form follow Function (Behaviour) or does Function follow Form?Answer: Form follows failure. Architectural styles evolve after years of trial and error.What do we mean by form then?Jim Coplien offers the example of a bottle plant. The bottle is the structure. The form (mold) could be injected with a variety of materials and still provide it's value. The FORM is the bottle's ESSENSE. The space created gives it's use. Pleasing asthetics makes us want to use it. This is a BIG DEAL!

Value = Crossing the Chasm

Stability != StaticCodify Business processes so we don't have to worry about them.

Embodies the critical design decisions that typify a system.Constraints paradoxically give us freedom!

Significance of design decisions need to be understood and assessed.

Goals of Architecture

Reduce Cost of Change

Reduce Coupling/Increase Cohesion

Support Locality of Decision Making

Shared Vision Upon Which Whole Team Can Proceed

Reduces the significance of decisions because the hard decisions have been made and make the easy ones easier.Making easy decisions first constrain your options and make hard decisions harder.

Larry ConstantineCoupling is the degree to which each program module relies on each one of the other modules.Cohesion is a measure of how strongly-related or focused the responsibilities of a single module are.In a highly-cohesive system, code readability and the likelihood of reuse is increased, while complexity is kept manageable.

Loosely coupled systems allow for decomposition based on Time (when we need to know/decide) rather than strictly based on Code Structure.

Enterprise Architecture
Pitfalls

Bigger Budgets, Lowered Expectations

Throw It Over the Wall Design

Beautiful Works of Fiction

People confuse the rules of drawing with the rules of construction not realizing that they are not the same. -- Leon Battista Alberti Italian Renaissance Architect (1404-1472)

Never the intention (except perhaps for Vendors!) but often the result. Attaching the word Global to it almost guarantees it will never be delivered.

Distributed development means you can't silo your architecture decision making yet that's what most companies do with their Ivory Tower Architects.If your architects aren't producing code to back up their designs then you have a problem.Coplien's version of Conway's Law - "If the parts of an organization (e.g. teams, departments, or subdivisions) do not closely reflect the essential parts of the product, or if the relationship between organizations do not reflect the relationships between product parts, then the project will be in trouble. ... Therefore: Make sure the organization is compatible with the product architecture."

Blueprints document the FINAL decisions once completed.Not only Customers but also Designers get enthralled by the beautify of large UML diagrams so that they forget the Business Justifications. This is not a new problem.

Heavy documentation actually eliminates the ability to determine the significance of a decision.

Enterprise Architecture
Pitfalls

Magazine Architecture

Don't forget about the people who will besubjected to your system!

Magazine Architecture is pretty pictures of empty rooms before you put the people into them.

Keep it REAL.

Make it sustainable!

How Much Architecture?

Big Upfront Designvs.No Upfront Designvs.Rough Upfront Design

BUFD Classic Waterfall FAILDesign Movement from 1980s. ISO-9001CASE Tools Knowledgeware's ADW/ TI's IEFProgrammers would become obsolete once this code generation stuff started working.Couldn't deal with EMERGENT requirements.Presumed to know things we can't possibly have known therefore doomed to fail to deliver VALUE to stakeholders from the beginning.

NUFD suggested by early XP/TDD proponents. Basically a myth. Having 10-20 years domain knowledge helps but what if it's the first time you're doing this?

RUFD Rough sketch of map. Point out land marks and things to watch out for.Explore options.Result must be working code.

Agile Values

"Programs must be written for people to read, and only incidentally for machines to execute."
Hal Abelson
(Structure and Interpretation of Computer Programs, Second Edition)

"Having the faculty of quick motion. Nimble. Active. Readiness." Oxford English Dictionary

An Architecture makes you Ready. James Coplien

Software Development is a Human Endeavor

Agile as a process recognizes and aligns itself with this realization better than any other.

So what is the CORRECT definition of Agile?

Agile is an adjective not a NOUN or VERB.

To be Agile you must first be strong.

How do we achieve readiness?

Agile Architecture

An Agile ModelThe Agile Manifesto Utah 2001

Individuals and interactions over processes and toolsWorking software over comprehensive documentationCustomer collaboration over contract negotiationResponding to change over following a plan

Agile is a Direction, not a Destination. There is more than one path!

Agile Architectural Values

Mayo-Smith Pyramid

Beware: Grandiose Designs Incur Grandiose RisksScope fixed, budget & schedule may suffer.

Focus: Immediate, practical functionality maximizes value of each increment while reducing risk. Scope flexible, budget, schedule under control.

Focus is on ALWAYS delivering VALUE to CUSTOMER.

To deliver value we must manage risk!

Classic Waterfall / Big Upfront Design

If you fix scope then budget & schedule become variables (and they never go down).

Pharoh StoryPharoh got two levels down and died... huge waste.

Deliver value early & often.

Fix your budget & schedule then focus on delivering incremental value as early as possible.

LEAN vs AGILE (OPTIONAL)

For our purposes they are equivalent. Difference is priority of focus when executing.

Initial reaction of an Agile team when encountering an obstable is to go around it.

Initial reaction of a Lean team when encountering an obstable is to remove it.

Agile Architecture How-to

Agile is a reaction against methodological excesses"Plans are useless, but planning is everything." Dwight D. Eisenhower

Put a Stick in the Ground

Design Lives in Code

Fight methodolofical excess. Rejects Ivory Tower Architects & Silo'd teams.Focus on DOING.Piecemeal growth, local adaption.

Sometimes reactions can go too far. Don't abandon planning when you abandon over detailed plans.

How to get started doing?It's OK to know stuff. Leverage local domain knowledge.Document your assumptions & be prepared to change them as you learn new things.Find the stable parts of the system (typically data)

Don't build big documents.Build shared (executable!) vision.Make docs that summarize what the code provides details for.Write an email don't call it a document!

Agile Architecture How-to

SCRUM (An actual discipline!)Everybody all together from the beginning.

Test Driven Development & Continuous IntegrationYou can't implement what you can't test.

SCRUM (Jeff Sutherland 1993) inspired by LEAN and the Toyota Way. High Innovation, High parallelism. Working on the edge of chaos.Time boxing, incremental & iterative development + standup meetings from Bell LabsDon't work overtime.Can't fit arbitrary work to an arbitrary schedule.

Small Cross functional teams - no silosWe will deliver what we can to an agreed upon level of quality.

Constant design. Everybody's an architect.Automation and frequent execution & feedback critical.

How else can you actually measure what value is being delivered or that you've met your agreed-upon quality levels?No more optional than double entry ledgers for accountants or clean room procedure for surgeons.

SPIKEsIdentify with certainty those things that are uncertain.As they are also User Stories and prioritized together there is local control over when this value/risk must be identified. Not all risk is equal. Managing risk mitigation is essential.

Iteration ReviewsFrequent reviews and feedback loops gets the project on track and also revaluates how well the process is working for us in the first place.

Architecture without the Architect

No Software Architects in Asia (Few Anywhere)

Think Like an Architect (identify value stream/fit into ecosystem)

Send out Scouting Parties (Fail Fast)

Hire a Guide (proper use of consultants)

(SKIP IF LESS THAN 15 MINUTES REMAINING)Takes 10-15 years of solid experience in a variety of technologies to become an architect.Zero Technical Career Paths == Lots of incredibly smart people with little experience and little exposure managing 20 other people one chapter behind them. This is an issue that will take 10-20 years to fix if we start today. No movement towards that however.Have to import them until then. Demand is insanely high. (Auto mechanic anecdote)