Implementing the Third Principle of the 12-Factor App in Spring Boot and Kubernetes

Introduction In this article, we will implement the third principle of the 12-Factor Application methodology in a Spring Boot and Kubernetes environment. Doing so allows us to avoid common problems such as: Applications running with incorrect configuration for a specific environment Delegating the responsibility for correct configuration to the DevOps role rather than developers Minimizing risk related to misconfiguration When working across multiple environments with microservices, a common anti-pattern causes frequent issues — particularly in production. This pattern consists of assuming that everything has been compiled correctly with the right configuration. Instead, this tutorial demonstrates how to properly implement the third principle of the 12-Factor App methodology. As stated in the 12-Factor App documentation: "The twelve-factor app stores config in environment variables (often shortened to env vars or env). Env vars are easy to change between deploys without changing any co