Uyuni

Uyuni handles the unglamorous half of infrastructure work: patching, configuration and lifecycle management across a Linux estate. It is the upstream of SUSE Multi-Linux Manager, so this is enterprise systems management with the badge removed, not a weekend project.

GPL-2.0 and free. It manages SUSE, Red Hat, Debian, Ubuntu and openSUSE clients, handles content staging, and owns the software channels your servers pull packages from. Java underneath, and a substantial install that wants a dedicated server rather than a container on a laptop.

Solo and small teams: far too much machinery for the problem. Medium and large teams running dozens or hundreds of Linux hosts under a compliance requirement: this is the free version of something companies pay real money for.

The catch is weight. Uyuni is heavy to install, heavy to operate, and its documentation quietly assumes you already speak SUSE. Ansible or Foreman will get a smaller estate patched for a fraction of the setup cost.