systems management systems – with GUI and w/o GUI

• https://en.wikipedia.org/wiki/List_of_systems_management_systems
• https://en.wikipedia.org/wiki/Foreman_(software) – a rather lively project as of 2021 – has a GUI – (apparently) cross-platform
• https://en.wikipedia.org/wiki/Spacewalk_(software) – the Spacewalk project was discontinued in May 2020 – has a GUI
• https://theforeman.org
• https://en.wikipedia.org/wiki/Ansible_(software) – (apparently) command line oriented
• https://en.wikipedia.org/wiki/Puppet_(software) – (apparently) command line oriented
• https://en.wikipedia.org/wiki/Chef_(software) – (apparently) command line oriented

The Foreman’s “currently” latest “Quickstart Guide”, amongst others for e.g. CentOS 7:

• https://theforeman.org/manuals/latest/quickstart_guide.html