StatefulSet

whoami/statefulset.yml

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: whoami-ss
  namespace: __NAME__
spec:
  selector:
    matchLabels:
      app: whoami-ss
  serviceName: whoami-ss
  replicas: 3
  template:
    metadata:
      labels:
        app: whoami-ss
    spec:
      containers:
        - name: whoami
          image: jwilder/whoami

And apply

https://kubernetes.io/docs/concepts/services-networking/service/#headless-services

whoami/service-headless.yml

apiVersion: v1
kind: Service
metadata:
  name: whoamis
  namespace: __NAME__
spec:
  clusterIP: None
  selector:
    app: whoami-ss
  ports:
    - port: 80
      targetPort: 8000

Test with

curl whoami-ss-0.whoamis
curl whoami-ss-1.whoamis

Prevent kubernetes autmatically re-creating by setting spec.updateStrategy.type

whoami/statefulset.yml

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: whoami-ss
  namespace: __NAME__
spec:
  updateStrategy:
    type: OnDelete
  selector:
    matchLabels:
      app: whoami-ss
  serviceName: whoami-ss
  replicas: 3
  template:
    metadata:
      labels:
        app: whoami-ss
    spec:
      containers:
        - name: whoami
          image: jwilder/whoami

You have reached the end of this section! Continue to the next section:

7. HorizontalPodAutoscaler