Templating and Kubernetes operators

On most modern platforms, we might have some kind of declarative configuration to describe the desired state of our applications. In the easiest case, this could be a YAML or JSON file. In such a configuration, we could find things such as the name of a platform object, the container that should be started, the number of replicas, and so on. In Kubernetes, a typical deployment configuration looks like this:

apiVersion: apps/v1kind: Deployment
metadata:
  name: my-cloudy-app
spec:
  replicas: 3
  selector:
    matchLabels:
      app: my-cloudy-app
  template:
    metadata:
      labels:
        app: my-cloudy-app
    spec:
      containers:
      - name: my-cloudy-app
    ...