Defining the Consensus Problem

Most problems in distributed systems space share a common trait that characterizes most, if not all, of them.

It’s the fact that the various nodes of a distributed system try to reach an agreement on a specific thing.

• In the case of a distributed transaction, it’s whether a transaction has been committed or not.
• In the case of message delivery, it’s whether a message has been delivered or not.

This underlying property is common in many more problems in the distributed systems space.

As a result, researchers formally defined this problem and researched possible solutions, since these can then be used as building blocks for more complicated problems. This is known as the consensus problem.