Ideally, infrastructure as code covers all aspects required to define the whole environment, including runtimes, networking, and configuration. Using container technologies and container orchestration greatly supports and simplifies this approach. As mentioned earlier, confidential content such as credentials should not be put under version control. This should be configured manually on the environment by an administrator.

Configuration that differs in several environments can be represented using multiple files in the project repository. For example, it makes sense to include subfolders for each environment. The following image shows an example:

The contents of the configmap.yaml file include the specific config map contents as well as potentially different namespace definitions. As mentioned in the previous chapter, Kubernetes namespaces are a way to differentiate environments. The following code shows an example of a specific production config map:

---
kind: ConfigMap
apiVersion: v1
metadata:
  name: hello-cloud-config
  namespace: production
data:
  application.properties: |
    hello.greeting=Hello production
    hello.name=Java EE
---