Nagios Plugins - Monitoring

1. Introduction

Nagios is an open-source monitoring system that enables organizations to identify and resolve IT infrastructure issues before they affect critical business processes. Nagios plugins are scripts or executable programs that extend Nagios's monitoring capabilities by providing checks on various resources, services, or applications.

2. Key Concepts

3. Installation

To install Nagios plugins, follow these steps:

1. Download the latest Nagios plugins from the official site.
2. Extract the downloaded tarball.
Note: Use the command tar -xzf nagios-plugins-x.x.x.tar.gz to extract.
3. Change to the extracted directory.
4. Run the configuration script:

./configure

5. Compile and install:

make && sudo make install

4. Creating Custom Plugins

Creating a custom plugin involves writing a script that adheres to the Nagios plugin API. Below is a simple example of a shell script that checks disk usage:

#!/bin/bash
                THRESHOLD=80
                USAGE=$(df / | grep / | awk '{ print $5 }' | sed 's/%//g')

                if [ "$USAGE" -gt "$THRESHOLD" ]; then
                    echo "CRITICAL - Disk usage is above ${THRESHOLD}%"
                    exit 2
                else
                    echo "OK - Disk usage is at ${USAGE}%"
                    exit 0
                fi

Make sure to make your script executable:

chmod +x your_script.sh

5. Best Practices

To ensure efficient monitoring with Nagios plugins, consider the following best practices:

• Always check return codes (0 for OK, 1 for WARNING, 2 for CRITICAL).
• Log outputs for troubleshooting.
• Use descriptive names for custom plugins.
• Test plugins locally before deploying to Nagios.
• Document your plugins for future reference.

6. FAQ