PostgreSQL 12 High Availability Cookbook - Third Edition

How it works...

We start by downloading and installing etcd so that we have a distributed communication layer for Patroni to use. The file we download should contain the documentation as well, but we only need to install etcd and etcdctl. These two command-line utilities either launch etcd or send it arbitrary instructions while it's running.

Much like PostgreSQL, etcd also uses a write-ahead log (WAL) for data durability. Therefore, we need a storage location for this WAL data. By default, etcd will create a subdirectory from where it was launched, which we don't really want if our intent is to establish and interact with the same etcd cluster every time.

Now, we must configure etcd on all of the PostgreSQL servers that comprise the Patroni ...