Agent availability and offline handling in Jenkins - Mini Project: Build & Apply

Agent availability and offline handling

📖 Scenario: You are managing a Jenkins server that uses multiple agents (nodes) to run jobs. Sometimes agents go offline due to maintenance or network issues. You want to track which agents are online and which are offline to manage your builds better.

🎯 Goal: Build a simple Jenkins pipeline script that lists all agents, checks their availability status, and prints whether each agent is online or offline.

📋 What You'll Learn

Use Jenkins pipeline Groovy script syntax

Access Jenkins instance to get all agents

Check each agent's availability status

Print agent name and status (online/offline)

💡 Why This Matters

🌍 Real World

In real Jenkins environments, agents can go offline due to maintenance or network issues. Monitoring their availability helps keep builds running smoothly.

💼 Career

DevOps engineers and Jenkins administrators need to manage agent availability to ensure continuous integration and delivery pipelines are reliable.

1

Get all Jenkins agents

Write a Jenkins pipeline Groovy script line to get all agents from the Jenkins instance and store them in a variable called agents.

Jenkins

// Your code here to get all Jenkins agents and assign to agents

Need a hint?

Use Jenkins.instance.nodes to get the list of all agents.

2

Prepare a status map

Create an empty map called agentStatus to store each agent's name and its online/offline status.

Jenkins

def agents = Jenkins.instance.nodes
// Create an empty map called agentStatus

Need a hint?

Use [:] to create an empty map in Groovy.

3

Check each agent's availability

Use a for loop with variable agent to iterate over agents. Inside the loop, check if agent.getComputer().isOnline() is true. If yes, set agentStatus[agent.getNodeName()] = 'online', else set it to 'offline'.

Jenkins

def agents = Jenkins.instance.nodes
def agentStatus = [:]
// Loop over agents and set their status in agentStatus map

Need a hint?

Use agent.getComputer().isOnline() to check if the agent is online.

4

Print agent availability status

Use a for loop with variables name and status to iterate over agentStatus. Print each agent's name and status in the format: Agent: <name> is <status>.

Jenkins

def agents = Jenkins.instance.nodes
def agentStatus = [:]
for (agent in agents) {
    if (agent.getComputer() != null && agent.getComputer().isOnline()) {
        agentStatus[agent.getNodeName()] = 'online'
    } else {
        agentStatus[agent.getNodeName()] = 'offline'
    }
}
// Print each agent's name and status

Need a hint?

Use println("Agent: ${name} is ${status}") to print the status.