© conchango 2006 Agile Architecture Microsoft Architect Insight Conference Howard van Rooijen ([email protected])

© conchango 2006 www.conchango.com

Agile Architecture

Microsoft Architect Insight Conference

Howard van Rooijen ([email protected])

http://blogs.conchango.com/howardvanrooijen

Simon Evans ([email protected])

http://blogs.conchango.com/simonevans


The Shift in Mentality

‘If I've got six months to build a system,

then I'll spend six months building it.

I'll also spend six months designing it,

and another six months testing it.

The good news is that it's the same six months.’

Ron Jeffries

http://www.xprogramming.com/


Failure Rates

The Methodology didn’t work

The Solution didn’t work


Feature Use


Agile Adoption in 2005

• Yes (37%)• No (45%)• Maybe (18%)


Manifesto for Agile Software Development

We are uncovering better ways of developing software by doing it

and helping others do it. Through this work we have come to value:

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.


Scrum Process


Why Do We Architect Solutions?

Reduce the risk in delivering solutions that are fit for purpose


Recipe for Successful Software

‘easy to use’

‘scalable’

‘accessible’‘perform well’

‘easy to maintain’

‘extensible’

‘secure’

‘cost effective’


Facets of Design

SOLUTION

“easy to use”

“scalable”

“performs well”“a

cces

sible

”

“easy to maintain”

“cost effective”“e

xtens

ible”

“secure”

END USER

PRODUCT OWNER

IT SUPPORT

DEVELOPER

SYS ADMIN


Designing Your Solution

• No two solutions are exactly the same• Assess how important each facet of design is to your project’s

success• Only make the solution as complex as it needs to be• Good design always means tradeoffs


Cost of Complexity

High Importance

Low Importance

Low Effort High Effort

Complex / Expensive

Easy / Cheap


Understanding Project Complexity

• Gain the vision for the project• Work only at the conceptual level

• Set out design goals for the project

• Assess likely solutions to the design goals

• Do not focus on a single solution or technology

• Assist in the creation of the product backlog• Propose preferred technologies• Gain commercial backing and trust• Scale the work to the project complexity• No prototypes

Sprint Zero


Breaking Down the Backlog

• Each item on the backlog must be a deliverable business feature that you can produce and demonstrate within one sprint

• The development team can add technical items to the backlog• The more granular the backlog, the more accurate the estimates …• … but more effort goes into estimating more granular backlogs• Keep product backlog items meaningful to the business• Do not be afraid of changing estimates again and again – the

estimates are as much for the team as for the business


Horizontal vs. Vertical Architecture (1)

FACADE

BUSINESS PROCESS

DATA ACCESS

ENTITIES

SQL Server



FACADE

BUSINESS PROCESS

DATA ACCESS

ENTITIES

SQL Server

FEATURE 1

FEATURE 2

FEATURE (X)



• Horizontal Architecture (Contract)+ Design interfaces that span the

breadth of the product backlog.

+ Devote time to selecting namespaces.

+ Consider component-level architectural dependencies.

- Do not code any implementation until the feature is started from the sprint backlog

- Writing implementation code before you start the feature will introduce waste and risk not completing the feature from the sprint backlog.

• Vertical Architecture (Feature)+ Complete demonstrable features that

will provide value to the business.

+ Ensure the team has a good understanding of related product backlog items in order to make informed decisions.

+ Assist the product owner in selecting high business impact and high technical risk features first.

- Do not attempt to deliver individual features before conducting group design and agreeing contracts.

- Failure to conduct enough group design sessions will cause software rewrites and force knowledge silos within the team.


Causes of Design Reworking

• Ineffective communication of the technical vision• Not enough group design sessions• Lack of clarity of requirements• Lack of team experience• Poor understanding of development / design standards• Pretending that completed work is ‘done’


Minimise Development Complexity

• Reuse as much as possible• Use existing frameworks• Use well-documented patterns and practices• Borrow other peoples’ ideas• Rely on your own experiences

• Invest in good engineering practices to reduce friction• The stub is your best friend

• ASP.net provider model


Group Design

• Timeboxed sessions for the whole team to contribute• Sessions should be conducted iteratively• Six minds are better than one• Conducted informally• Visual Studio 2005 class designer (via projector) provides stub

creation• Group design sessions should lead to pair programming and

working alone• Group design sessions avoid silos of knowledge


Consolidating Architecture

• Retrofit well-designed reusable components from projects with proven architectures

PROJECT 1 PROJECT 2 PROJECT 3

Security Component 1

Security Component 2

Security Component 3+


Pyramid of Engineering Practices


The ole of an Agile Architect

• Enable the team to deliver potentially shippable code. Every month.• Focus on delivery of features.• Communicate vision of the project.• Empower the team to make architectural decisions.• Be involved in the formation of the product backlog.• Eliminate irreversibility in software designs.• Minimise software waste.


Scrum for Team System

Sprint

Product Backlog Item



Sprint Backlog Item

Sprint Retrospective Item






Feedback / Questions

Find us at the conference or contact us via the methods below:

[email protected]

http://blogs.conchango.com/howardvanrooijen

[email protected]

http://blogs.conchango.com/simonevans

www.scrumforteamsystem.com

www.scrum-master.com

Documents

© conchango 2006 Agile Architecture Microsoft Architect Insight Conference Howard van Rooijen ([email protected])