Paxos
Simple paxos
Paxos is an algorithm used by distributed systems as a method of acheivng consensus. It consists of three entities: proposers, acceptors and learners. A proposer is responsible for... proposing values to the acceptors. Acceptors, receive values from propsers and reply to the proposers if they accepted the value or not. Finally, learners are responsible for storing the accepted value.
Starting with simple paxos, or the synod protocol; this describes a way for a group of nodes to agree on a single value, a ballot is started by a proposer by sending a proposed value to a group of acceptors. This proposal is identifiable by its proposal number.
An acceptor can accept or reject the proposed value. An acceptor can only accept at most one value. The value is accepted if and only if the proposal number is higher than any previous proposal number.
The value is determined to be chosen once a majority or quorum of acceptors have accepted the proposal. this ensures consistency