Agent connection methods (SSH, JNLP) in Jenkins - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is SSH in Jenkins agent connection?

SSH (Secure Shell) is a method Jenkins uses to connect to an agent by securely logging into the agent machine over the network using a username and password or SSH keys.

beginner

What does JNLP stand for and how does it work in Jenkins?

JNLP stands for Java Network Launch Protocol. Jenkins agents use JNLP to connect by running a Java program on the agent machine that connects back to the Jenkins controller.

intermediate

Which Jenkins agent connection method requires the agent to initiate the connection?

JNLP requires the agent to initiate the connection to the Jenkins controller, which is useful when the agent is behind a firewall or NAT.

intermediate

What are the security benefits of using SSH for Jenkins agents?

SSH provides encrypted communication and strong authentication using keys or passwords, reducing the risk of unauthorized access to the agent machine.

intermediate

When might you prefer JNLP over SSH for Jenkins agent connection?

You might prefer JNLP when the agent cannot accept incoming connections due to firewall restrictions or when you want the agent to connect to the controller on its own schedule.

Which Jenkins agent connection method requires the master to connect to the agent?

A Neither SSH nor JNLP

B JNLP

C Both SSH and JNLP

D SSH

SSH requires the Jenkins controller to connect to the agent machine, while JNLP agents connect back to the controller.

What protocol does JNLP use to launch the Jenkins agent?

A Java Network Launch Protocol

B FTP

C HTTP

D SSH

JNLP stands for Java Network Launch Protocol, which is used to start the Jenkins agent as a Java application.

Which method is better if the agent is behind a strict firewall blocking incoming connections?

A Both are equally good

B SSH

C JNLP

D Neither works

JNLP agents initiate the connection to the controller, so they work better behind firewalls blocking incoming connections.

What is a common authentication method used by SSH for Jenkins agents?

A Username and password

B Both A and C

C SSH keys

D No authentication

SSH supports both username/password and SSH key authentication for secure access.

Which Jenkins agent connection method requires Java to be installed on the agent machine?

A JNLP

B SSH

C Both SSH and JNLP

D Neither

JNLP agents run a Java program on the agent machine, so Java must be installed.

Explain the differences between SSH and JNLP agent connection methods in Jenkins.

Think about who initiates the connection and what protocols are used.

Describe scenarios where you would choose JNLP over SSH for Jenkins agent connection.

Consider network restrictions and agent environment.