Root Fan

TL;DR: A repmgr cluster handles automatic failover — but applications still need to know which node is the current primary.

Keepalived solves this with a floating Virtual IP (VIP) that moves automatically to whichever node holds the primary role.

This guide adds a VIP to an existing PostgreSQL 18 + repmgr cluster on Ubuntu 24.04 using Keepalived 2.x.

Every step has been run live on a real cluster and the output verified.

PostgreSQL does not include automatic failover out of the box.
When the primary goes down, someone has to promote the standby manually — which means downtime.
repmgr adds an automatic failover daemon (repmgrd) that monitors the cluster and promotes the standby within seconds when the primary fails.
This guide walks through setting up a two-node PostgreSQL 18 cluster with streaming replication and automatic failover on Ubuntu 24.04, using repmgr 5.x.
Every step has been run live on a real cluster and the output verified.