Jenkins : Slave Setup Plugin

Plugin Information

View Slave SetupPlugin on the plugin site for more information.

This plugin prepares slaves for build execution by letting you copy files and execute scripts before the slave gets used.

It also allows you to start and stop slaves on demand from the master node.

Label-based setup

The slave setup plugin gets executed for a slave, if the given label expression matches and on:

  • Jenkins startup as a slave gets connected.
  • Save of the Jenkins configuration page if the "deploy on save now" checkox is checked.
  • New or re-connection of a slave.

When you install this plugin, it adds a new system configuration section that lets you specify a list of slave setup items. Each of them have to following properties:

Property

Description

Example

pre-launch script

Name of a pre-launch script relative to the jenkins home directory. This can be used to start the slave machine, before Jenkins tries to ssh it.

./prelaunch.sh

prepare script

Name of a prepare script relative to the jenkins home directory (not the setup files directory, this has changed in v1.6). This can be used to aggregate files into the setup files directory, patch them, pack them, and so on...

./prepare_files.sh

setup files directory

Absolute path to the directory that will be copied to the slave.  The contents of this directory are copied to the home directory of the slave.

/var/jenkins/devSlaveFiles

setup script after copy

Name of the script that should be executed on the slave after all files are copied. The script should be part of the files to copy.

./slave_setup.sh

deploy on save now

If checked, this slave setup item will be executed on save of the jenkins configuration page.

checked

Label Expression

Like jobs a slave setup item can be configured to be executed only on the slaves that match the Label Expression.

"slaves", "!selenium", "slave1 OR slave2"

First the directory gets copied, then the script gets run. The execution of the script is reported to the slave log. When it fails, the slave is not marked as online, so ill-prepared slaves never enter the slave pool.

This provides the administrator of the system an opportunity to prepare slaves to the state suitable for build execution. This works particularly well in conjunction with tools like Puppet that has higher-level support for this kind of task.

On-demand slave setup 

This plugin also provides you a per-slave "start" and "stop" script configuration specific for on-demand slaves.

Once installed, you will have an additional "Launch method" (1) for this case: 

this one lets you specify the "Start" (2) and "Stop" (3) scripts, and on top of that you will be able to specify the "conventional" connection (4) method for reaching the slave after it has been started.

You will likely also want to specify that you want this node to be online only when Jenkins needs it (5).

The figure below shows the configuration that you may want to use if your on-demand slave is an Amazon EC2 instance.

(show full size)

NOTE: if your jobs need the slave to be up for being scheduled, you may end up in a situation where no jobs are scheduled because the slaves are offline, and the slaves are not started because no jobs are scheduled.

A common cause of this situation might be that you are polling Git by the Git plugin, and "Fast remote polling" (polling from the master instead of the slave) is disabled or not working. See the Git plugin documentation on how to get the "Fast remote polling" working.

Changelog

Version 1.10 (July 1, 2016)

  • Fixed JENKINS-31175 - License missing in source code
  • Added per-slave start & stop scripts specifically for on-demand slaves. This also resolves JENKINS-20489 - start slave on demand and don't power off afterwards

Version 1.9 (June 17, 2015)

  • Fixed JENKINS-28297 - NPE in pre-launch Script for Jenkins Versions bigger than 1.609

Version 1.8 (September 23, 2014)

  • Fix a bug when Slave could not be started of no labels of the pre-launch Scripts match.

Version 1.8 (September 23, 2014)

  • Fix a bug when Slave could not be started of no labels of the pre-launch Scripts match.

Version 1.7 (September 22, 2014)

  • Expose NODE_TO_SETUP_NAME and NODE_TO_SETUP_LABELS (JENKINS-24107)
  • Help files are displayed now
  • Possibility to add pre-launch scripts which will be executed before the slave is launched

Version 1.6 (July 2, 2012)

  • Fixed error on using empty Slave Setup Config Item.

Version 1.5 (June 18, 2012)

  • Added the possibility to create a list of slave setup items to support different setups.
  • Added field for prepare script to provide the possibility to prepare the files to be copied to a slave.

Version 1.4 (Mar 08, 2012)

  • Added checkbox to enable setup deployment on save of the system configuration page.
  • Added label field to filter slaves to be used for setup deployment.

Version 1.0 (Sep 17, 2011)

  • Initial version