Continuous Delivery in a Complex S.O.A.

Richard LennoxSenior Architect, Skyscannerwww.skyscanner.net

@richardlennoxwww.linkedin.com/in/rlennox

Skyscanner

Why Continuous Delivery?

Continuous Delivery“How long would it take your organisation to deploy a change that involved just a single line of code?” Do you do this on a repeatable, reliable basis?”

…is a set of practices and principles aimed at building, testing and releasing software reliably and repeatably at a necessary frequency.

Keeping systems production-ready throughout development, so that they can be released to users at any time

Goals of CD

Quality Cycle Time

Efficiency

Core Practices Continuous Integration Automated Testing [Automated] Configuration Management Deployment Pipelines

Continuous Integration

Continuous Integration Everyone Commits to the Mainline Every

Day Automate the Build Make Build Self Testing Every Commit triggers build on Integration

server Fail Fast, Feedback Faster

http://martinfowler.com/articles/continuousIntegration.html

Automated Testing

Build Quality In

“Cease dependence on mass inspection to achieve quality. Improve the process and build quality into the product in the first place”

W. Edwards Deming

Automated TestingCost of

Execution Time

Number of Tests

Unit Tests

Integration Tests

UI Tests

100% Automated

100% Manual

Acceptance Tests

Configuration Management

Configuration Management Stuff we make is valuable Not just the source code :

Application configurationOS setupMachine ConfigurationTestsDocumentation

Where possible should live with the code

Deployment Pipeline

Deployment Pipeline

8 Principles / Patterns Reliable & Repeatable delivery process Automate (almost) everything Take the pain early and more often Source control is king Done or Done, Done = Released, Build quality in Everybody is responsible Continuous improvement

Service Oriented Architecture

Definition:- software architecture design pattern- structured collections of discrete software

modules (the services)- collectively provide the complete functionality

of a large software application

Vision of Necessary State

Individual ServicesWorking of own heartbeat

Considerations for CD in SOA

Focus on 5 key areas- Partitioning the SOA into governed

Deployable Units- Consistent Deployment Pipelines- Just Enough Test Automation Coverage- Real Time Metrics- Aligning the Delivery Conditions

Deployable Units 1+ Services to be deployed Single, built once Package Comprising:

Releasable Software Tests Application Configuration“Install” / Rollback ScriptsAssets

One mainline (Trunk) per Deployable Unit Decoupled Deployments and Rollbacks Fits naturally with S.O.A.

But not necessarily 1:1 ratio

Not a 1:1 ratio?

Service Governance

a.k.a. Making sure people do the right things – Anne Thomas Manes, OOP2007

SLAs Versioning Fault Tolerance and Resilient Engineering

Service Compatibility Governance

Client(v1)

Client(v2)

Service(v1)

Service(v2)

Deployment

Deployment

Rollback

Rollback

Databases Services may have own DB

Versioned with

Some DBs act as integration pointsLegacy

Must be treated as any other ServiceSame levels of governance,Same SLAsSame Tolerance to failures

Consistent Deployment Pipelines

Early Integration not Late Integration Consistency, Consistency and Consistency

Build ScriptsTools of choice,Test Frameworks and UsageEverything where possible

Canary Release Patterns Aligning to a single flow for all components

Just Enough Test AutomationCost of

Execution Time

Number of Tests

Unit Tests

Integration Tests

Acceptance Tests

UI Tests

100% Automated

100% Manual

Dependency Test Triggers

C D E

B

A

Y

XX

ZI

Real Time Metrics Safety Net for canary release Coupled with Operational Metrics Individual Service defined

Asynchronous Data Loaders – throughputFailing Fast and Hard

Cascading Healthchecks1

F G D

E

A

H

C

I

B

2 3

Aligning Delivery Conditions

Culture Agile Practices First Breaking down Silos Getting over the fear of collaboration Trunk Based Development over Feature

Branching Discipline in Continuous Integration Dealing with breaks

Summary Architecture has a huge impact on the

ability to Continuously Deliver Comes with its own set of challenges and It is the right thing for modern web-based

businesses.

Thanks!

Richard LennoxSenior Architect, Skyscannerwww.skyscanner.net

@richardlennoxwww.linkedin.com/in/rlennox

Questions?