Day 28: Exploring Jenkins Agents for Distributed Builds

In today’s task, we delve into Jenkins Agents, an essential component for scaling and optimizing your CI/CD pipeline. By setting up a Jenkins agent, we can distribute workloads, making builds faster and more efficient. Let’s break down the tasks for today.

Task 01: Setting Up a Jenkins Agent

1. Creating a New Agent Node

To distribute builds, the first step is setting up a new agent node in Jenkins. This involves configuring the master server to communicate with the agent node.

2. Setting Up an AWS EC2 Instance

• Launch a new AWS EC2 instance to act as your Jenkins agent.
• Use a lightweight instance type (e.g., t2.micro) to keep costs minimal while testing.
• Ensure the instance has Java installed as Jenkins requires Java to operate.

3. Establishing Master-Agent Communication

• Key Pair Exchange: Generate an SSH key pair and copy the public key to the agent's ~/.ssh/authorized_keys. Test the connection using the ssh command from the master to the agent.
• Node Configuration:Go to Manage Jenkins > Nodes and Clouds > New Node on the Jenkins dashboard.Provide the node details, such as name, labels, and SSH credentials.Save and verify that the agent successfully connects to the master.

4. Verifying Agent Status

Check the agent's status in Manage Jenkins > Nodes. A successful setup will show the node as online and ready for builds.

Task 02: Leveraging the Agent for Jobs

1. Running Previous Jobs on the Agent

With the agent node operational, revisit the Jenkins jobs created in Day 26 and Day 27:

• The Declarative Pipeline from Day 26.
• The Docker-Integrated Pipeline from Day 27.

Modify the pipeline configuration to specify the new agent by adding a label:

pipeline {
    agent { label 'docker-agent' }
    stages {
        stage('Build') {
            steps {
                sh 'docker build -t trainwithshubham/django-app:latest .'
            }
        }
    }
}        

2. Labeling and Build Triggers

• Assign a label (e.g., docker-agent) to the new agent in the node configuration.
• Update the Jenkins jobs to use this label, ensuring they execute on the correct node.

Benefits of Using Jenkins Agents

1. Scalability: Distribute workloads across multiple nodes.
2. Isolation: Use dedicated agents for specific jobs, e.g., Docker builds or resource-intensive tasks.
3. Optimized Resources: Reduce the load on the master node by offloading builds to agents.

Conclusion

Setting up a Jenkins agent is a vital step toward scaling your DevOps infrastructure. By distributing builds and assigning specific tasks to agents, you enhance efficiency and keep your CI/CD pipeline robust. Use today’s experience to refine your setup and prepare for more advanced Jenkins configurations! ??

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