Since our backend API is a stateless application, we don't need to deploy a StatefulSet like we did with Elasticsearch. We can simply use a simpler Kubernetes Object that we've encountered already—Deployment.

Create a new manifest at manifests/backend/deployment.yaml with the following content:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: backend
  labels:
    app: backend
spec:
  selector:
    matchLabels:
      app: backend
  replicas: 3
  template:
    metadata:
      labels:
        app: backend
    spec:
      containers:
      - name: backend
        image: d4nyll/hobnob:0.1.0
        ports:
        - containerPort: 8080
          name: api
        - containerPort: 8100
          name: docs
        env:
        - name: ELASTICSEARCH_HOSTNAME
          value: "http://elasticsearch"
        - name: ELASTICSEARCH_PORT
          value: "9200"
        ...

For the .spec.template.spec.containers[].env field, add in the same environment variables that we passed in to our Docker image from the previous chapter (the ones we stored inside our .env file). However, for the ELASTICSEARCH_PORT variable, hard-code it to "9200", and for ELASTICSEARCH_HOSTNAME, use the value "http://elasticsearch".