This document discusses how to scale Jenkins jobs as the number of jobs grows very large. It describes moving from individual Jenkins jobs to defining pipelines as code. The key steps are: 1) defining pipelines using a Job DSL plugin; 2) refactoring duplicated DSL code into reusable libraries; and 3) configuring pipelines through property files instead of code. This allows generating and securing pipelines for multiple projects through a seed job that is triggered by source code management hooks. The end result is "automation of automation" through self-service, secure, simple and extensible pipeline management.

1. JOB SCALABILITY IN JENKINS
GETTING OUT OF THE JOB JUNGLE
JBAM - June 1st 2017 - @DamienCoraboeuf

2. WHO AM I?
▸ Damien Coraboeuf (@DamienCoraboeuf)
▸ Born to Java in 1996
▸ Working in Continuous Delivery since 2008
▸ Automating pipelines @ FIS
I’ll be your guide on this journey

3. > 10 jobs?
> 100 jobs?
> 1000 jobs?
> 10000 jobs?

4. 2052
3244
4365
6668
10373
0
2000
4000
6000
8000
10000
12000
Oct-15 Jan-16 May-16 Aug-16 Nov-16 Mar-17 Jun-17
Jobs
10373 JOBS IN 3 YEARS

5. STORY OF A JOURNEY OUT OF THE JUNGLE

6. THE MAP Short introduction to Jenkins
Birth of a pipeline
Manual mode
The Job DSL
Branching and its consequences
Pipeline as code
Pipeline as not code
Automation of automation
We want to get there
Look, there is another
beach here!
Do not go there!
💀
There are traps here!
💀

7. x✔
Three years ago in the
jungle…

8. JENKINS - JOBS & FOLDERS

9. JENKINS - JOB CONFIGURATION
Let’s get some sources…
Let’s run some build…
Let’s trigger another job…

10. PIPELINES
▸ Defining jobs
▸ Linking them together
▸ Running them in parallel or in sequence
▸ Some triggers are automatic, other ones are manual
BUILD
DEPLOY ENV 1
DEPLOY ENV 2
DEPLOY ENV 3
PUBLICATION RELEASE

11. A PIPELINE IS BORN
BUILD
DEPLOY ENV 1
DEPLOY ENV 2
DEPLOY ENV 3
PUBLICATION RELEASE
BUILD
DEPLOY ENV 1
DEPLOY ENV 2
DEPLOY ENV 3
PUBLICATION RELEASE
BUILD
DEPLOY ENV 1
DEPLOY ENV 2
DEPLOY ENV 3
PUBLICATION RELEASE
Commit 1
Commit 2
Commit 3

12. SO FAR SO GOOD
“Look Ma, I’ve built a pipeline!”
“Lovely. Now, build one for your sister.”

13. THE STORY
Product A
Product B
Project C
Maintenance 11.8
Maintenance 11.9
Maintenance 11.10
Maintenance 7.2
Maintenance 8.0
Maintenance 5.0
Check
Publication
WAS JBoss …
Promotion for QA
QAWAS QAJBoss …
Promotion for NFT
Sonar Fortify Perf
Promotion for delivery
Delivery
Auto Manual
Pipeline
Products & Projects Branches
…

14. THE STORY
Jenkins team
> 10000 jobs and growing…

16. In order to scale, we want:
✔ Self service
✔ Security
✔ Simplicity
✔ Extensibility

17. “What are we?”
“Developers!”
“What do we do?”
“Code!”
“Why do we do it?”
“Automation!”

18. JOB DSL PLUGIN - START OF THE JOURNEY OUT OF THE JUNGLE
▸ Define a job using a Groovy based DSL!

19. JOB DSL PLUGIN
▸ Very well supported
▸ Very good documentation
▸ Supports most of the plugins
▸ Built-in extensibility: inline or DSL extensions

20. JOB DSL PLUGIN
▸ Folders & views
▸ … automatic triggers upon generation
▸ … using files in workspace

21. JOB DSL PLUG-IN
▸ This remains code…

22. JOB DSL PLUGIN - SEED JOB
▸ DSL based generation done from a job
▸ Can generate and/or update other jobs
▸ Can even run while jobs are running :)
SEED JOB GENERATED JOB(S)
DSL SCRIPT
Generates
Accesses (SCM or inline)
GENERATED JOB(S)
GENERATED JOB(S)

23. PIPELINE EVOLUTION
▸ One Seed DSL job is all very good but…
▸ Pipeline evolves with the code
Builds
this code
Builds
this code
W
ill fail for this code
New platform being
added
Job for the
new platform

24. BRANCHING
▸ One Seed DSL job is all very good but…
▸ Different pipelines for different
branches
develop
release/2.0
Pipelines for releases
might be more complex
Release job

25. PIPELINE VERSIONS
▸ Where do we put the DSL script?
develop
release/2.0
Pipelines for releases
might be more complex
DSL.GROOVY
DSL.GROOVY
DSL.GROOVY

26. PIPELINE AS CODE
▸ Your pipeline is linked to the code it builds
▸ Define your pipeline in your code
Project
src
pom.xml
job-dsl-script.groovy

27. PIPELINE CODE DUPLICATION
▸ We can now generate a pipeline for any branch, any commit
▸ It evolves with your branches and is merged like any other piece of code
▸ That’s good enough for 1 project
▸ With several (many) projects, the level of DSL code duplication explodes!
DEVELOP FEATURE/BIG RELEASE/1.0
DSL SCRIPT DSL SCRIPT DSL SCRIPT
DEVELOP FEATURE/BIG RELEASE/1.0
DSL SCRIPT DSL SCRIPT DSL SCRIPT
DEVELOP FEATURE/BIG RELEASE/1.0
DSL SCRIPT DSL SCRIPT DSL SCRIPT
DEVELOP FEATURE/BIG RELEASE/1.0
DSL SCRIPT DSL SCRIPT DSL SCRIPT
DEVELOP FEATURE/BIG RELEASE/1.0
DSL SCRIPT DSL SCRIPT DSL SCRIPT

28. PIPELINE CODE DUPLICATION
▸ Job DSL code duplication has the same issues than
production code duplication
DEVELOP FEATURE/BIG RELEASE/1.0
DSL SCRIPT DSL SCRIPT DSL SCRIPT
DEVELOP FEATURE/BIG RELEASE/1.0
DSL SCRIPT DSL SCRIPT DSL SCRIPT
DEVELOP FEATURE/BIG RELEASE/1.0
DSL SCRIPT DSL SCRIPT DSL SCRIPT
DEVELOP FEATURE/BIG RELEASE/1.0
DSL SCRIPT DSL SCRIPT DSL SCRIPT
✘ ✘ ✘ ✘ ✘ ✘
✘✘✘✘✘✘
DEVELOP FEATURE/BIG RELEASE/1.0
DSL SCRIPT DSL SCRIPT DSL SCRIPT
DEVELOP FEATURE/BIG RELEASE/1.0
DSL SCRIPT DSL SCRIPT DSL SCRIPT
✘✘✘✘✘✘
DEVELOP FEATURE/BIG RELEASE/1.0
DSL SCRIPT DSL SCRIPT DSL SCRIPT
DEVELOP FEATURE/BIG RELEASE/1.0
DSL SCRIPT DSL SCRIPT DSL SCRIPT
✘✘✘✘✘✘
DEVELOP
DSL SCRIPT
DEVELOP
DSL SCRIPT
✘
✘
DEVELOP
DSL SCRIPT
✘
DEVELOP
DSL SCRIPT
✘
LEASE/1.0
L SCRIPT
LEASE/1.0
L SCRIPT
LEASE/1.0
L SCRIPT
LEASE/1.0
L SCRIPT
DEVELOP FEATURE/BIG RELEASE/1.0 DEVELOP FEATURE/BIG RELEASE/1.0 DEVELOPLEASE/1.0

30. PIPELINE LIBRARIES TO THE RESCUE
▸ Pipeline is code
▸ Reuse of code through versioned libraries
DEVELOP FEATURE/BIG RELEASE/1.0
DSL SCRIPT DSL SCRIPT DSL SCRIPT
PIPELINE DSL LIBRARY
1.1 1.0
Normal project
Can be tested
Can be released

31. PIPELINE DSL LIBRARY B
PIPELINE LIBRARIES TO THE RESCUE
▸ DSL libraries as code libraries
DEVELOP FEATURE/BIG DEVELOP
DSL SCRIPT DSL SCRIPT DSL SCRIPT
PIPELINE DSL LIBRARY A
1.1 1.0
COMMON DSL LIBRARY
1.0
Dependencies
2.0

32. ARE WE DONE?
▸ We can describe a pipeline using a DSL
▸ The pipeline is defined together with the code it builds
▸ The DSL can use libraries to reduce code duplication
?

33. NOT QUITE…
▸ This is not enough to really scale
▸ We still have to write some DSL
▸ Self service ✔
▸ Security ✘
▸ Simplicity ✘
▸ Extensibility ✔

34. PIPELINE AS “NOT CODE”
▸ Let’s describe the pipeline using a properties file
▸ Which pipeline library & which version
▸ Configuration properties - specific to the library
▸ Property file format ubiquitous
▸ No code running on the master
▸ Can be used for reporting on all the pipelines!

35. PIPELINE AS PROPERTIES
seed.properties

36. PIPELINE AS… PROPERTIES
SEED JOB
SCM Repository
Jobs
Gets the
seed.properties
Gets the pipeline
library version
Configures and runs
the pipeline library

37. PIPELINE AS… PROPERTIES
SEED JOB

38. PIPELINE AS… METADATA
▸ The seed.properties files provide a wonderful way to
do reporting on all projects and branches
DEVELOP FEATURE/BIG RELEASE/1.0
SEED SEED SEED
DEVELOP FEATURE/NEW RELEASE/3.4
SEED SEED SEED
seed.properties seed.properties
“Give me all branches using JDK 6”
“Give me all projects having no SonarQube scan”
“…”

39. SEED PLUGIN
▸ Putting everything together
▸ https://github.com/jenkinsci/seed-plugin
▸ Allows to generate:
▸ projects folders
▸ branches pipelines
▸ based on seed files (properties and/or DSL)
▸ integration with hooks

40. SEVERAL INTEGRATION MODES
SEED.PROPERTIES
SEED PLUGIN
SEED.PROPERTIES
SEED.GROOVYSEED.GROOVY
PIPELINE LIBRARY PIPELINE LIBRARY
BRANCH PIPELINE
95% 4%
1%

41. GENERATION STRUCTURE
SEED
PROJECT GENERATOR
PROJECT FOLDER
BOOTSTRAPPING
BRANCH GENERATOR
BRANCH FOLDER
BRANCH JOB 1
BRANCH JOB 2
BRANCH JOB 3
BRANCH JOB 4
GENERATION
Project teamJenkins team

42. PIPELINE SECURITY
SEED
A FOLDER
A GENERATOR
BOOTSTRAPPING
A team
Jenkins team
B team
GENERATION
A BRANCHES
A PIPELINES
B FOLDER
B GENERATOR
B BRANCHES
B PIPELINES

43. GENERATION - HOW IT LOOKS LIKE
BOOTSTRAPPING
GENERATION
GENERATION

44. AUTOMATION

45. HOOKS
▸ Generations can be automated using hooks at SCM level
▸ Support for GitHub, BitBucket, generic HTTP calls (for SVN)
▸ Configurable. For example:
BRANCH CREATION
SCM EVENT
Seed plug-in
COMMIT
SEED CHANGED
BRANCH DELETION
PIPELINE EVENT
Generation
Triggers the pipeline
Regenerates the pipeline
Deletes the pipeline

46. RESPONSIBILITIES
Jenkins team
Pipeline libraries
Develops and
maintains
Development team
Seed files
Defines
Seed plug-in
SCM
Triggers

47. WHAT DID WE JUST ACHIEVE?
▸ Automation of automation
▸ Self service ✔
▸ Pipeline automation from SCM
▸ Security ✔
▸ Project level authorisations
▸ No code on the master
▸ Simplicity ✔
▸ Property files
▸ Extensibility ✔
▸ Pipeline libraries
▸ Direct job DSL still possible

48. OUT OF THE JUNGLE…

49. SEED & PIPELINE PLUGIN
▸ The Seed plugin will keep working
▸ It can already generate pipeline jobs (Job DSL)
▸ But overlap of functionalities
Branch pipelines
Pipeline as code
SEED
PIPELINE
Hook integration
Pipeline as properties
Community & support
Pipeline libraries
Pipeline script library

50. SEED IN PIPELINE PLUGIN
▸ The Seed plugin as extension of the Pipeline plugin
Branch pipelines
Pipeline as code
SEED
PIPELINE
Hook integrationPipeline as properties
Community & support
Pipeline libraries
Pipeline script library

51. THANKS YOU!
Thanks to the
Jenkins
Belgium Area
Meetup
Contact:
▸ http://nemerosa.com
▸ @DamienCoraboeuf