The article provides a detailed guide on setting up PostgreSQL database replication using Docker containers, specifically configuring a primary database and a hot standby database to mitigate the risk of downtime in a 3-tier web application architecture. It explains how database replication involves replicating data from a primary database to secondary databases, which can serve read operations when the primary database is down, thereby ensuring the application's availability. The tutorial further demonstrates connecting these databases to a Django application, where a database router is configured to direct read and write queries to the appropriate database. The guide also touches on creating a replication slot to maintain data consistency and offers insights into enhancing the setup with additional replicas or promoting a secondary database to primary status if needed. Moreover, the article encourages exploring tools like Earthly for build automation to optimize the development process.