Introduction

In Chapter 5, Pods, we learned that Pods are the minimal unit of deployment in Kubernetes. Pods can have multiple containers, and each container can have a container image associated with it. This container image generally packages the target application that you plan to run. Once the developers are satisfied that the code is running as expected, the next step is to promote the code to testing, integration, and production environments.

Easy, right? One problem, however, is that as we move our packaged container from one environment to another, although the application remains the same, it needs environment-specific data, for example, the database URL to connect to. To overcome this problem, we can write our applications in such a way that the environment-specific data is provided to the application by the environment it is being deployed into.

In this chapter, we will discover what Kubernetes provides to associate environment-specific data with our application...