I have a Rails Server A in Country A, Rails Server B in Country B, and Rails Server C in Country C, all using Devise and Omniauth.
A user can sign up in all 3 servers. But when he logs in to Server A, that server should update Server B and C, updating the user's record there that he is currently logged into Server A. How can I do this in Rails? I've heard that this process requires interprocess communication and RPC and that RabbitMQ could be used for it.
Rather than doing something complicated with RPC and all that, why not just have Server A make a POST request to an API on Server B and C? You could simply POST the same data changed over to those and make the same update. That's what I would probably do.