Having some Linux servers up and running I checked out monitoring tools like Nagios, Zabbix, Cockpit or Prometheus. For small setups, home labs, or lightweight environments, those solutions can feel like using a sledgehammer to crack a nut. In this post, I’ll show you how to build a lightweight monitoring agent using nothing more than a Bash script, MQTT, and Node-RED. The script collects key metrics from your server — disk usage, memory consumption, CPU load, and available package upgrades — then publishes them to an MQTT broker. From there, Node-RED visualizes the data in a clean, real-time dashboard. The result? A simple but powerful monitoring system that works across multiple servers, scales with your needs, and gives you instant visibility into the health of your infrastructure. And the best part: you control every piece of it.
