[box type=”note” align=”” class=”” width=””]This article is an excerpt from a book by David Blomquist and Tomasz Janiszewski titled Apache Mesos Cookbook. From this book, you will get to know tips and tricks along with best practices to follow when working with Mesos.[/box]
In today’s tutorial, we will learn about building and enabling the Jenkins Mesos plugin.
Building the Jenkins Mesos plugin
By default, Jenkins uses statically created agents and runs jobs on them. We can extend this behavior with a plugin that will make Jenkins use Mesos as a resource manager. Jenkins will register as a Mesos framework and accept offers when it needs to run a job.
How to do it
The Jenkins Mesos plugin installation is a little bit harder than Marathon. There are no official binary packages for it, so it must be installed from sources:
- First of all, we need to download the source code:
curl -L
https://github.com/jenkinsci/mesos-plugin/archive/mesos-0.14.0.tar. gz | tar -zx
cd jenkinsci-mesos-plugin-*
- The plugin is written in Java and to build it we need Maven (mvn):
sudo apt install maven
- Finally, build the package:
mvn package
If everything goes smoothly, you should see information, that all tests passed and the plugin package will be placed in target/mesos.hpi.
Jenkins is written in Java and presents an API for creating plugins. Plugins do not have to be written in Java, but must be compatible with those interfaces so most plugins are written in Java. The natural choice for building a Java application is Maven, although Gradle is getting more and more popular. The Jenkins Mesos plugin uses the Mesos native library to communicate with Mesos. This communication is now deprecated, so the plugin does not support all Mesos features that are available with the Mesos HTTP API.
Enabling the Jenkins Mesos plugin
Here you will learn how to enable the Mesos Jenkins plugin and configure a job to be run on Mesos.
How to do it…
- The first step is to install the Mesos Jenkins plugin. To do so, navigate to the Plugin Manager by clicking Manage Jenkins | Manage Plugins, and select the Advanced tab. You should see the following screen:
- Click Choose file and select the previously built plugin to upload it. Once the plugin is installed, you have to configure it. To do so, go to the configuration (Manage Jenkins | Configure System). At the bottom of the page, the cloud section should appear. Fill in all the fields with the desired configuration values:
- This was the last step of the plugin installation. If you now disable Advanced On- demand framework registration, you should see the Jenkins Scheduler registered in the Mesos frameworks.
Remember to configure Slave username to the existing system user on Mesos agents. It will be used to run your jobs. By default, it will be jenkins. You can create it on slaves with the following command:
adduser jenkins
- Be careful when providing an IP or hostnames for Mesos and Jenkins. It must match the IP used later by the scheduler for communication. By default, the Mesos native library binds to the interface that the hostname resolves to. This could lead to problems in communication, especially when receiving messages from Mesos. If you see your Jenkins is connected, but jobs are stuck and agents do not start, check if Jenkins is registered with the proper IP. You can set the IP used by Jenkins by adding the following line in /etc/default/jenkins (in this example, we assume Jenkins should bind on 10.10.10.10):
LIBPROCESS_IP=10.10.10.10
We learnt about building and enabling Jenkins Mesos plugin. You can know more about how to configure and maintain Apache Mesos from Apache Mesos Cookbook.
