Zero-Downtime PostgreSQL Major Version Upgrades in Containers: The Problem Nobody Talks About

Running PostgreSQL in containers is one of the smartest infrastructure decisions a team can make — until the day you need to upgrade across a major version. Then it becomes one of the most painful ones. This post walks through why major PostgreSQL upgrades are uniquely hard in containerized environments, the common approaches teams reach for (and why they hurt), and how pg-upgrade — a Docker-native upgrade toolkit — turns a weekend-long migration into a reproducible, CI-validated three-step proc