Alert/message forwarding in distributed system

I need to design a message forwarding system in a distributed system of two or more servers.

Like out of all the group of servers in the distributed system, one will be primary server and rest all will be fallback/secondary servers. So if some message is generated on this secondary servers they should be forwarded to the primary server for further processing. A message can be anything like like some health related information or simple network connectivity status.

I am very new to distributed systems and haven't worked on inter server communication.

Please suggest some technologies/design that I might learn to solve this particular problem.