LibreVault
Librevault is a data synchronization app, designed to keep files same on
different computers over the network.
You can run librevault-daemon on a headless server. It doesn’t require X
server. Configuration can be created using simple json files or using
GUI to connect to librevault-daemon as its controller.
https://librevault.com
https://github.com/Librevault/librevault
https://github.com/Librevault/librevault/issues/71
(from redmine: issue id 6472, created on 2016-11-21)