pg_auto_failover setup with two nodes

Learn how to build, configure, and test a practical PostgreSQL High Availability cluster using pg_auto_failover. This hands-on guide walks you through a complete 2-node Vagrant-based lab setup with AlmaLinux 9, PostgreSQL 16, and pg_auto_failover. You will learn how to configure the monitor node, create primary and standby PostgreSQL nodes, manage systemd services, verify cluster health, perform planned switchovers, simulate automatic failover, and validate data consistency after role changes. Designed for PostgreSQL DBAs, Linux admins, DevOps engineers, and database reliability engineers, this guide focuses on real implementation steps, operational commands, troubleshooting awareness, and production considerations such as authentication, SSL, client routing, HAProxy, pgBouncer, RPO/RTO planning, and monitor placement. By the end of this eBook, you will have a working PostgreSQL HA lab and a clear understanding of how pg_auto_failover manages PostgreSQL node promotion, demotion, recovery, and automatic failover.