The latest Jenkins LTS disposes of the term master for the main node, from the release notes:
Replace the term "master" for the main Jenkins application with "controller" or "built-in node" in user interface strings and documentation. New installations get the new node and label immediately. Existing installations do not change the node name (e.g. NODE_NAME environment variable) or label of the built-in node until an administrator explicitly performs the migration. If a job definition, Pipeline definition, or tool installer reference must be tied to the built-in node, it should use the label "built-in". (Upgrade guide - Built-In Node Name and Label Migration)
And in the web UI of release-jenkins the following note is displayed:
The word "master" is being retired as the term for the main Jenkins process and the built-in node. The main process is now called "controller" and the built-in node is called just "built-in node". The UI has been updated with these changes. The following features are also affected:
- The implicit label of the built-in node changes from master to built-in.
- The built-in node's NODE_NAME environment variable also changes from master to built-in.
These changes could affect build behavior, so are not applied automatically. Before you apply these changes, you should do the following:
Review label assignments in job configurations and tool installers for uses of master label. Any such label assignments will not match the built-in node after migration. Besides updating these assignments, you could also explicitly add the master label to the built-in node.
Review use of the NODE_NAME environment variable in build scripts.
For the CI Jenkins, that might well affect the Gearman plugin which comes hardcoded with the term master in its code :-\