How to do it...

Let's see how to modify the Jenkins configuration.

1. In the top-level directory of Jenkins, look for the config.xml file. Edit the line with numExecutors, changing the number 2 to 3:

<numExecutors>3</numExecutors> 

1. Restart the server. You will see that the number of executors has increased from the default two to three.
2. Plugins persist their configuration through XML files. To prove this point, look for the thinBackup.xml file. You will not find it unless you have installed the thinBackup plugin.