I have several node servers running on AWS (but they might be running anywhere).

An admin user can trigger a database save on one server (via an Express endpoint) which will in turn require all servers to reload that particular record. So, a particular server needs to be able to trigger an event onto N other servers.

Since the node processes are potentially on different servers, I can't use a Unix socket. And since I don't know in advance how many servers there are, I assume I will need to have one specific server which will "orchestrate" all of the other ones (see: each server "registers" and "pushes" events to that particular server).

What is the easiest, simplest solution to achieve this? I am talking about minimal amount of code and moving parts.