Jenkins Jenkins Agents and Distributed Builds

Question 1

What is a Jenkins agent (formerly called slave)?

Accepted Answer

A machine that connects to the Jenkins controller to run build jobs

Answer

A Jenkins agent is a machine (physical, virtual, or container) that connects to the controller and executes builds assigned to it.

Question 2

What protocol does Jenkins use by default to communicate with agents?

Accepted Answer

JNLP/Remoting protocol (TCP)

Answer

Jenkins uses the Remoting protocol over TCP (JNLP) by default for controller-to-agent communication, with WebSocket as an alternative.

Question 3

What is a Jenkins label used for in relation to agents?

Accepted Answer

Associating jobs or pipeline stages with specific agents or agent groups that have matching labels

Answer

Labels are applied to agents and referenced in jobs or pipeline `agent` directives to route builds to agents with specific capabilities.

Question 4

What does the `agent { label 'linux' }` directive do in a Declarative Pipeline?

Accepted Answer

Runs the pipeline on any agent with the 'linux' label

Answer

The `label 'linux'` agent directive tells Jenkins to run the pipeline on any available agent that has been tagged with the 'linux' label.

Question 5

What is the Jenkins agent.jar (remoting.jar) file?

Accepted Answer

The Java executable that runs on the agent machine and communicates with the controller

Answer

The agent.jar (remoting.jar) is the Java process launched on the agent machine that establishes and manages communication with the Jenkins controller.

Jenkins Practice Test

Jenkins Practice Test

Jenkins Jenkins Agents and Distributed Builds