A PostgreSQL primary loses power at 2am. Writes resume in under thirty seconds. The on-call engineer reads the alert in the morning, sees that the cluster healed itself, and goes back to coffee. That is the outcome PostgreSQL high availability is supposed to deliver.A working Patroni cluster, on its own, gets you partway there. The leader election runs. A standby gets promoted. The cluster state in etcd stays consistent. Then the application keeps trying to reach an IP address that points at the wrong node now, the old primary needs a manual rejoin, and the on-call engineer is on a conference bridge instead of in bed.