Scaling Jenkins with Docker and Apache Mesos @ O’Reilly Media

I will be delivering this online course for O’Reilly media, October 18, 2016 7:00pm CEST

Scaling Jenkins with Docker and Apache Mesos

Continuous integration and continuous delivery at scale

Join Carlos Sanchez for a study in running Jenkins at scale. He’ll share his experience using Docker and Apache Mesos to create one of the biggest Jenkins clusters to date. You’ll drill down into the details with Carlos to get a better understanding of how Apache Mesos works. Together you’ll explore the challenges of running containerized and distributed applications (particularly JVM ones) through a real-world use case. By the end of this course, you’ll have a solid grounding in using these popular open source technologies for continuous integration and continuous delivery at scale.

What you’ll learn—and how you can apply it

By the end of this live, online course, you’ll understand:

  • How Apache Mesos works and how Docker containers are executed in a Mesos cluster
  • How Jenkins can use a Mesos cluster as a provider to provision build agents on demand
  • How Java applications behave inside a Docker container

And you’ll be able to:

  • Create a Apache Mesos cluster for local development using Docker Compose
  • Create Jenkins jobs that are executed dynamically based on demand
  • Use Jenkins Pipelines to execute jobs in one or more Docker containers

This course is for you because…

  • You’re a build/release engineer or are interested in deploying Docker at scale
  • You work with Jenkins or other Java applications
  • You want to become a Docker expert!

JavaOne: From Monolith to Docker Distributed Applications

I’ll be speaking again this year at JavaOne: From Monolith to Docker Distributed Applications, sharing our experience running the Jenkins platform on Docker containers using Apache Mesos.

You can also find me in the CloudBees booth in the exhibitors area.

Docker is revolutionizing the way people think about applications and deployments. It provides a simple way to run and distribute Linux containers for a variety of use cases, from lightweight virtual machines to complex distributed microservice architectures.

But migrating an existing Java application to a distributed microservice architecture is no easy task, requiring a shift in the software development, networking, and storage to accommodate the new architecture.

This presentation provides insights into the experience of the speaker and his colleagues in creating a Jenkins platform based on distributed Docker containers running on Apache Mesos and Marathon and applicable to all types of applications, especially Java- and JVM-based ones.

Jenkins World 2016

Jenkins World will take place again this year (September 13-15) in Santa Clara, CA, and I will be speaking again about my experience with Jenkins and Docker in my session Scaling Jenkins with Docker: Swarm, Kubernetes or Mesos?

To register, go to and enter in code JWCSANCHEZ for a 20% discount.

This year in Jenkins World:

  • 50+ sessions from organizations such as: Electronic Arts, FINRA, GerritForge, Google, NPR, Riot Games, Shutterfly, Splunk and Verizon.
  • Keynotes from Kohsuke Kawaguchi, Sacha Labourey and Gary Gruver.
  • Free Jenkins and CloudBees Jenkins Platform certification exams.
  • Networking with the LARGEST gathering of Jenkins users in the world.



Next Events: DevOpsPro Vilnius, MesosCon, Boulder JAM & Docker meetups, Open DevOps Milan

I’ll be traveling in the following weeks, speaking at

DevOpsPro in Vilnius, Lithuania: From Monolith to Docker Distributed Applications (May 26th)

MesosCon North America in Denver, CO: CI and CD at Scale: Scaling Jenkins with Docker and Apache Mesos (June 1st)

Jenkins Area Meetup and Docker Boulder meetup in Boulder, CO: CI and CD at Scale: Scaling Jenkins with Docker and Apache Mesos (June 2nd)

Open DevOps in Milan, Italy: Continuous Delivery and the DevOps Way (June 22nd)

If you are around just ping me!

Webinar: Scaling Jenkins with Docker and Kubernetes

Webinar: Scaling Jenkins with Docker and Kubernetes

Check the video at

Scaling Docker with Kubernetes V1: Kubernetes, Google Container Engine, Jenkins at Scale

Scaling Docker with Kubernetes V1

My latest article at InfoQ, covering Kubernetes v1, Google Container Engine, Jenkins at scale and the Jenkins Kubernetes plugin.

Kubernetes is an open source project to manage a cluster of Linux containers as a single system, managing and running Docker containers across multiple hosts, offering co-location of containers, service discovery and replication control. It was started by Google and now it is supported by Microsoft, RedHat, IBM and Docker amongst others.

Building Docker images with Puppet

Docker-logoEverybody should be building Docker images! but what if you don’t want to write all those shell scripts, which is basically what the Dockerfile is, a bunch of shell commands in RUN declarations; or if you are already using some Puppet modules to build VMs?

It is easy enough to build a new Docker image from Puppet manifests. For instance I have built this Jenkis slave Docker image, so here are the steps.

The Devops Israel team has built a number of Docker images on CentOS with Puppet preinstalled, so that is a good start.

FROM devopsil/puppet:3.5.1

Otherwise you can just install Puppet in any bare image using the normal installation instructions. Something to have into account is that Docker images are quite simple and may not have some needed packages installed. In this case the centos6 image didn’t have tar installed and some things failed to run. In some CentOS images the centosplus repo needs to be enabled for the installation to succeed.

FROM centos:centos6
RUN rpm --import && \
    rpm -ivh

# Need to enable centosplus for the image libselinux issue
RUN yum install -y yum-utils
RUN yum-config-manager --enable centosplus

RUN yum install -y puppet tar

Once Puppet is installed we can apply any manifest to the server, we just need to put the right files in the right places. If we need extra modules we can copy them from the host, maybe using librarian-puppet to manage them. Note that I’m avoiding to run librarian or any tool in the image, as that would require installing extra packages that may not be needed at runtime.

ADD modules/ /etc/puppet/modules/

The main manifest can go anywhere but the default place is into /etc/puppet/manifests/site.pp. Hiera data default configuration goes into /var/lib/hiera/common.yaml.

ADD site.pp /etc/puppet/manifests/
ADD common.yaml /var/lib/hiera/common.yaml

Then we can just run puppet apply and check that no errors happened

RUN puppet apply /etc/puppet/manifests/site.pp --verbose --detailed-exitcodes || [ $? -eq 2 ]

After that it’s the usual Docker CMD configuration. In this case we call Jenkins slave jar from a shell script that handles some environment variables, with information about the Jenkins master, so it can be overriden at runtime with docker run -e.


#ENV JENKINS_MASTER http://jenkins:8080

CMD su jenkins-slave -c '/bin/sh /'

The Puppet configuration is simple enough

node 'default' {
  package { 'wget':
    ensure => present
  } ->
  class { '::jenkins::slave': }

and Hiera customizations, using a patched Jenkins module for this to work.

# Jenkins slave
jenkins::slave::ensure: stopped
jenkins::slave::enable: false

And that’s all, you can see the full source code at GitHub. If you are into Docker check out this IBM research paper comparing virtual machines (KVM) and Linux containers (Docker) performance.