Poor Man's Nagios

Extremely simple Nagios/Icinga2 NRPE-based server monitor -- ideal for monitoring your monitor server in a small setup.

Overview

After having set up a small server farm monitored using Icinga2, I found myself in need of a simple way to monitor the monitoring server itself.

Not wanting to install and configure an entire second Icinga2 instance just to perform one simple monitoring action, I wrote this instead.

It implements a simple checking algorithm with a failure threshold, and sends alert emails via the local SMTP server.

Works for me.

This humble library provides the following:

• A base PoorMansNagios class, which handles the monitoring checks and alerting
• PoorMansMailer class, which handles sending alert emails
• poor-mans-nagios-cli.py: Wraps the base class for calling from CLI
• poor-mans-nagios.service: Example systemd service file.

Setup

Written in pure Python, 3.x required.

Dependencies

• PyYAML

The library does its work by leveraging the Nagios NRPE framework, so that will need to be properly installed/configured. This library needs access to the check_nrpe binary, and the monitored server needs a running NRPE daemon with a check configured.

You'll also need a running SMTP server, such as Postfix, capable of sending emails it receives locally.

Configuration

• Copy config.sample.yaml to config.yaml
• Edit to taste

The sample file is well-commented.

Usage

Execute poor-mans-nagios-cli.py --help for help.