ClearOS is a free and open source cloud-connected server, network, and gateway operating system. ClearOS is designed for small organizations and distributed environments. It offers an extensive list of features and integrated services. Based on CentOS and Red Hat Enterprise Linux, its source code is available mostly under the GPL version 2 software licence. ClearOS uses the CodeIgniter PHP framework to make life easier. See also Why ClearOS.
Most use cases covered by apps in various categories
FLOSS Weekly 168: Michael Proper and David Loper https://www.youtube.com/watch?v=EIBf9hE6hXQ