Startup script to set the System Properties

Step 1:

• Locate the Jenkins home directory. You can look into the existing system properties for ‘jenkins_home’ or execute ‘echo $JENKINS_HOME’ inside the jenkins server to get the Jenkins home directory.
• Say if your Jenkins home directory is ‘/var/jenkins_home’. Create a new directory with name ‘init.groovy.d’.

Step 2:

• Now change your working directory to ‘/var/jenkins_home/init.groovy.d’
• Within init.groovy.d directory create a new groovy script. Say ‘startup-properties.groovy’

Step 3:

• Copy the below content to the ‘startup-properties.groovy’ file

import jenkins.model.Jenkins
import java.util.logging.LogManager

/* Jenkins home directory */
def jenkinsHome = Jenkins.instance.getRootDir().absolutePath
def logger = LogManager.getLogManager().getLogger("")

/* Replace the Key and value with the values you want to set.*/
/* System.setProperty(key, value)*/
System.setProperty("hudson.model.WorkspaceCleanupThread.disabled", "true")
logger.info("Jenkins Startup Script: Successfully updated the system properties. Script location: ${jenkinsHome}/init.groovy.d")

Visit https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/lang/System.html?is-external=true#setProperty(java.lang.String,java.lang.String) to see how to use setProperty.

Step 4:

Restart the Jenkins server, you can manually restart the server using :

<Jenkins-server-URL>/restart or <Jenkins-server-URL>/safeRestart

• Use safeRestart when you have some job still running. It will wait till all the jobs are completed.

Step 5:

Check the logs after Jenkins restart: Manage Jenkins → System Log. You can see while server is starting, its executing the startup-properties.groovy script which is inside init.groovy.d directory.

For example, run the below scripts in Script Console to check the System Properties, you will see the required key and values.

println(System.getProperty("hudson.model.WorkspaceCleanupThread.disabled"))