PostgreSQL 12 High Availability Cookbook - Third Edition

The stack

By the time we're finished with this chapter, our complete architecture diagram will be far different from what we might normally expect:

We can see that each Patroni element only communicates with its own local Postgres instance. It also communicates with etcd and HAProxy in order to maintain the cluster in a healthy state. Because each of these vertical elements operates independently, we could continue adding Postgres nodes with managing Patroni elements almost indefinitely.

But first, we have to build it.

You can refer to the following links for more information: The Raft Consensus Algorithm: https://raft.github.io/HAProxy