How to perform a minor update of PostgreSQL in a Patroni cluster?

Minor PostgreSQL update in a Patroni cluster is usually performed with high availability and minimal downtime in mind. The main steps:

1. Update replicas one by one:

   • Stop Patroni on the replica.
   • Update PostgreSQL to the required minor version.
   • Start Patroni and wait for synchronization with the master.

2. After updating all replicas, perform a switchover to make one of the updated replicas the master.

3. Update the former master in a similar manner.

Thus, the update occurs without stopping the entire cluster. It is important to check compatibility beforehand and make a data backup.