I’m looking for a decentralized way to exchange messages (JSON) between two linux servers. The difficult thing is making sure the messages arrive in case of an outage. Its crucial, that no message gets lost and that connection is reastablished after an outage. So basically both servers need some kind of queue, which is saved on the hard drive. Additionaly, servers need to send ACK messages after a message arrives. Only after it’s certain, that the message arrived, can it be deleted.