This document discusses scaling a Jenkins master using Docker. It describes how the company Wyplay was using a single Jenkins master to manage over 500 jobs, which led to performance and reliability issues. It then explains how Wyplay set up multiple Docker containers running Jenkins masters to address these issues. It provides details on installing and configuring Jenkins in Docker containers, managing plugins, backups, and monitoring across multiple containerized masters. Finally, it discusses future directions like using orchestration tools and programmatically configuring Jenkins systems.

1. Scaling Your Jenkins Master with Docker
London, UK 23-24 June

2. #jenkinsconf
Contents
●
WHO: Wyplay
●
WHAT: Docker, Docker in Jenkins, Jenkins in Docker
●
WHY: Situation Before, Issues
●
HOW: Setup, Usage
●
WHERE: Future
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3. #jenkinsconf
Contents
●
WHO: Wyplay
●
WHAT: Docker, Docker in Jenkins, Jenkins in Docker
●
WHY: Situation Before, Issues
●
HOW: Setup, Usage
●
WHERE: Future
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4. #jenkinsconf
WHO am I
I Worked in Queueing Networks, Simulation,
Smartcards, now TV Software for Operators
– Develop Set-top-box OS (Canal+, Proximus, SkyIt,..)
– 80% of Developers
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5. #jenkinsconf
Contents
●
WHO: Wyplay
●
WHAT: Docker, Docker in Jenkins, Jenkins in Docker
●
WHY: Situation Before, Issues
●
HOW: Setup, Usage
●
WHERE: Future
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6. #jenkinsconf
WHAT: Docker
●
Company (Docker Inc)
●
Open Source (Apache license) platform for building,
shipping, running distributed applications
●
Technology: manage and run lightweight Linux
containers
– Isolation
– Portability, Shipping
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7. #jenkinsconf
WHAT: Docker in Jenkins
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●
Docker Plugin
– Dynamically provision
slaves
– Run build
– Tear-down slave
●
Slaves in the Cloud

8. #jenkinsconf
WHAT: Jenkins in Docker
●
Official Jenkins LTS
docker image
– From Cloudbees, sponsor
of DockerCon
– Open Source
https://github.com/jenkinsci/docker
– Easy to use
docker pull jenkins
docker run -p 8080:8080 jenkins
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9. #jenkinsconf
Contents
●
WHO: Wyplay
●
WHAT: Docker, Docker in Jenkins, Jenkins in Docker
●
WHY: Situation Before, Issues
●
HOW: Setup, Usage
●
WHERE: Future
9

10. #jenkinsconf
WHY: Situation Before
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●
One Master
– 34 attached slaves
– 527 jobs
– 78 plugins
– admin users
●
Fast-paced environment. No real control

11. #jenkinsconf
WHY: Issues
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●
Performance
●
Reliability
●
Inability to upgrade
●
Downtime
=> Projects spin-off masters
●
Security

12. #jenkinsconf
Contents
●
WHO: Wyplay
●
WHAT: Docker, Docker in Jenkins, Jenkins in Docker
●
WHY: Situation Before, Issues
●
HOW: Setup, Usage
●
WHERE: Future
12

13. #jenkinsconf
HOW: Setup for one master (1)
●
Three possibilities for /var/jenkins_home
– inside the container:
docker run -p 8080:8080 jenkins
– mounted from a host directory:
docker run -v <host-path>:/var/jenkins_home jenkins
– mounted from a data volume container:
docker run -v /var/jenkins_home --name=data busybox true
docker run --volumes-from=data jenkins
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14. #jenkinsconf
HOW: Setup for one master (2)
●
Summary for one master:
– pull the official Jenkins image:
$ docker pull jenkins
– create the data volume and master containers:
$ docker run -v /var/jenkins_home --name=frog-data
busybox true
– run the master container:
$ docker run -t -i -u root -p 8084:8080 -p 50004:50004
--volumes-from=frog-data --name=frog jenkins
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15. #jenkinsconf
HOW: Setup n masters
●
Launch an httpd dispatcher (e.g., Apache)
– 443 (https) → vhosts(name) → 808i
●
Launch docker containers:
– the Data Volume containers, with names
– the Jenkins masters containers linked with --volumes-
from and 808i / 5000i ports
– map each container port 8080 to host ports 8080+i
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16. #jenkinsconf
HOW: Usage
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Pressed
Json
DRAFT
Apache
cert.crt
privat.key
frog-data
polka-data
frog
Pressed
Json
DRAFT
pressed
.json
LIVE
Pressed
Json
DRAFT
Pressed
Json
DRAFT
polka
Pressed
Json
DRAFT
Pressed
Json
DRAFT
pressed
.json
LIVE
Pressed
Json
DRAFT
Pressed
Json
DRAFT
Frog.conf
ServerName
frog-ci.com
ProxyPass
localh:8084
X-F-Port443
g6-data
tools-data
443
8084
8080
8080
808i
--volumes
-from
--volumes
-from
50004
Slaves

17. #jenkinsconf
HOW: Admin Usage (1)
●
Install plugins (from /tmp/plugins)
$ docker run -t -i --rm --volumes-from=frog-data
-v /tmp:/tmp ubuntu bash
root@1a210c0a1846:/# cd /var/jenkins_home/plugins
root@1a210c0a1846:/# cp /tmp/plugins/* .
root@1a210c0a1846:/# exit
●
Similar technique for:
– full backup
– debug data (SCM Sync git repos, Plots csv, etc.)
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18. #jenkinsconf
HOW: Admin Usage (2)
●
Change image
– stop container, destroy, create a new one
$ docker stop frog
$ docker rm frog
$ docker run … --volumes-from=frog-data --name frog
$ docker logs -f frog
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19. #jenkinsconf
HOW: Admin Usage (3)
●
Three levels of backup
– Vmware: dump of entire docker server
– Docker: copy all Data Volume
– Jenkins: SCM Sync plugin
●
Three levels of monitoring
– Vmware, Docker, Jenkins
●
Security: Role Strategy plugin
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20. #jenkinsconf
Contents
●
WHO: Wyplay
●
WHAT: Docker, Docker in Jenkins, Jenkins in Docker
●
WHY: Situation Before, Issues
●
HOW: Setup, Usage
●
WHERE: Future
20

21. #jenkinsconf
WHERE: do we go from here?
● Orchestration
– manual setup ok for a few
– more => orchestration tool (e.g., Docker Compose)
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22. #jenkinsconf
WHERE: do we go from here?
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●
Docker vs Config/Automation tools (chef, puppet,
ansible, saltstack)
Before: use ansible to
setup hardware/VM,
install packages,
deploy code,
run app.
After: use ansible to setup
hardware/VM, install Docker,
run containers.
use Dockerfiles to install
packages, deploy code, run
app.

23. #jenkinsconf
WHERE: do we go from here?
●
Monitoring (docker level)
●
Find a way to “Configure System” programmatically
– LDAP
– Plugins upgrades
– TCP port for slaves
– Markup formatter
– SCM Sync, Roles, IRC, etc.
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24. #jenkinsconf
Thank You
@cmuller13 on twitter
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