Best way to share common data between multiple servers in c++

I am developing a c++ application that has 3 servers(each server acts as a node). These three servers need to communicate with each other to elect a leader among them. I am able to communicate with the servers but I am not sure how to count the max votes received for which server. Since the vote information is common for all three nodes I am not understanding what is the best way to implement that. I cannot use files or databases for this( I am implementing RAFT protocol). What would be the best way to implement this?