Slides from STV Tech Talks (Glasgow, UK) - 27 August 2013 -- Based on the experience of leading the current initiative to move towards Continuous Delivery at Skyscanner, I presented a view on 5 key focus areas that must be considered to make Continuous Delivery an achievable objective within a very complex Service Oriented Architecture.

1. Continuous Delivery
in a Complex S.O.A.
Richard Lennox
Senior Architect, Skyscanner
www.skyscanner.net
@richardlennox
www.linkedin.com/in/rlennox

2. Skyscanner

3. Why Continuous Delivery?

4. 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

5. Goals of CD
Quality Cycle Time

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

7. Continuous Integration

8. 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

9. Automated Testing

10. 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

11. Automated Testing
Cost of
Execution
Time
Number of Tests
Unit Tests
Integration Tests
UI Tests
100% Automated
100% Manual
Acceptance Tests

12. Configuration Management

13. Configuration Management
 Stuff we make is valuable
 Not just the source code :
 Application configuration
 OS setup
 Machine Configuration
 Tests
 Documentation
 Where possible should live with the code

14. Deployment Pipeline

15. Deployment Pipeline

16. 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

17. 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

18. Vision of Necessary State
Individual Services
Working of own heartbeat

19. 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

20. Deployable Units
 1+ Services to be deployed
 Single, built once Package Comprising:
 Releasable Software
 Tests
 Application Configuration
 “Install” / Rollback Scripts
 Assets
 One mainline (Trunk) per Deployable Unit
 Decoupled Deployments and Rollbacks
 Fits naturally with S.O.A.
 But not necessarily 1:1 ratio

21. Not a 1:1 ratio?

22. Service Governance
a.k.a. Making sure people do the right things –
Anne Thomas Manes, OOP2007
 SLAs
 Versioning
 Fault Tolerance and Resilient Engineering

23. Service Compatibility Governance
Client
(v1)
Client
(v2)
Service
(v1)
Service
(v2)
Deployment
Deployment
Rollback
Rollback

24. Databases
 Services may have own DB
 Versioned with
 Some DBs act as integration points
 Legacy
 Must be treated as any other Service
 Same levels of governance,
 Same SLAs
 Same Tolerance to failures

25. Consistent Deployment Pipelines
 Early Integration not Late Integration
 Consistency, Consistency and Consistency
 Build Scripts
 Tools of choice,
 Test Frameworks and Usage
 Everything where possible
 Canary Release Patterns
 Aligning to a single flow for all components

26. Just Enough Test Automation
Cost of
Execution
Time
Number of Tests
Unit Tests
Integration Tests
Acceptance Tests
UI Tests
100% Automated
100% Manual

27. Dependency Test Triggers
C D E
B
A
Y
XX
ZI

28. Real Time Metrics
 Safety Net for canary release
 Coupled with Operational Metrics
 Individual Service defined
 Asynchronous Data Loaders – throughput
 Failing Fast and Hard

29. Cascading Healthchecks
1
F G D
E
A
H
C
I
B
2 3

30. Aligning Delivery Conditions

31. 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

32. 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.

33. Thanks!
Richard Lennox
Senior Architect, Skyscanner
www.skyscanner.net
@richardlennox
www.linkedin.com/in/rlennox
Questions?