Application configuration and service discovery

So far, we have explored quite a few of K8s features and resources, but how do we do application configuration? We could add configuration files or environment variables to the container images during the build, but this is wrong. If you do so, for even the smallest configuration change, you’ll have to rebuild container images. Also, where you need to have different settings for different environments, you’ll need to maintain multiple images of the same application. Things get messy, complicated, and error-prone, so don’t do this.

Instead, the better approach in Kubernetes is to use ConfigMaps and Secrets.

ConfigMap

A ConfigMap is a resource to store non-confidential data and configuration settings in key-value pairs that can be consumed inside Pods as environment variables, command-line arguments, or configuration files. ConfigMaps do not provide secrecy or encryption, so they are not suitable for keeping...