PatchMon
Linux Patch Monitoring Automation Platform
...It centralizes patch status information from many hosts into a single dashboard where users can view inventories of outdated packages, track repositories per host, and organize machines into logical groups for easier oversight. Agents installed on each server make outbound-only connections to the PatchMon server, improving security by avoiding open inbound ports, while the server side provides role-based access control, user management, and a REST API for integrations. PatchMon also supports a customizable dashboard, detailed per-host metrics, and one-line installers for quick self-hosted deployment, making it suitable for both small clusters and larger fleets.