In this section, we will explore how to manage Jenkins nodes. Nodes are essential components in Jenkins that allow you to distribute the workload across multiple machines, improving performance and scalability. We will cover the following topics:

1. Understanding Jenkins Nodes
2. Adding a New Node
3. Configuring Node Properties
4. Managing Node Labels
5. Monitoring Node Performance

• Master Node: The main Jenkins server that handles:
  • Scheduling build jobs.
  • Dispatching builds to the worker nodes (agents).
  • Monitoring the agents.
  • Recording and presenting the build results.
• Agent Nodes: Machines that perform the actual build tasks. They can be physical, virtual, or cloud-based.

• Scalability: Distribute the build load across multiple machines.
• Isolation: Run builds in isolated environments to avoid conflicts.
• Performance: Improve build performance by leveraging multiple machines.

1. Navigate to Manage Jenkins:

   • Go to the Jenkins dashboard.
   • Click on "Manage Jenkins" from the left-hand menu.

2. Manage Nodes and Clouds:

   • Click on "Manage Nodes and Clouds".

3. Create a New Node:

   • Click on "New Node".
   • Enter a name for the node.
   • Select "Permanent Agent" and click "OK".

4. Configure Node Properties:

   • Description: Provide a description for the node.
   • Remote root directory: Specify the directory on the agent machine where Jenkins will store files.
   • Labels: Add labels to categorize the node.
   • Usage: Define how Jenkins should use the node (e.g., "Use this node as much as possible").
   • Launch method: Choose how Jenkins will connect to the agent (e.g., via SSH).

5. Save and Launch:

   • Click "Save".
   • Jenkins will attempt to connect to the agent using the specified launch method.

• Remote Root Directory: The directory on the agent machine where Jenkins will store files.
• Labels: Tags that help categorize and select nodes for specific jobs.
• Usage: Determines how Jenkins will utilize the node (e.g., "Use this node as much as possible" or "Only build jobs with label expressions matching this node").
• Launch Method: The method Jenkins uses to connect to the agent (e.g., SSH, JNLP, Windows service).

Labels are tags assigned to nodes that help categorize and select nodes for specific jobs. They are useful for:

• Targeting Specific Nodes: Run jobs on nodes with specific capabilities (e.g., OS type, installed software).
• Load Balancing: Distribute jobs across nodes with similar labels.

1. Navigate to the Node Configuration:

   • Go to "Manage Jenkins" > "Manage Nodes and Clouds".
   • Click on the node you want to configure.

2. Add Labels:

   • In the "Labels" field, enter the desired labels separated by spaces.
   • Click "Save".

Monitoring nodes helps ensure they are performing optimally and can handle the assigned workload. Key metrics to monitor include:

• CPU Usage: High CPU usage may indicate the need for more powerful hardware or additional nodes.
• Memory Usage: Insufficient memory can lead to build failures or slow performance.
• Disk Space: Ensure there is enough disk space for build artifacts and logs.

• Jenkins Node Monitoring Plugins: Plugins like "Monitoring" and "Node Usage Plugin" provide detailed insights into node performance.
• External Monitoring Tools: Tools like Nagios, Zabbix, or Prometheus can be integrated with Jenkins for comprehensive monitoring.

In this section, we covered the essentials of managing Jenkins nodes, including understanding their purpose, adding new nodes, configuring node properties, managing labels, and monitoring performance. Proper node management is crucial for optimizing Jenkins' performance and ensuring efficient build processes. In the next section, we will delve into configuring security in Jenkins to protect your CI/CD environment.