nginx-replica-set.yaml

apiVersion: v1
kind: Service
metadata:
  name: nginx
  labels:
    app: nginx
spec:
  ports:
  - port: 80
    name: web
  clusterIP: None
  selector:
    app: nginx
---
apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: web
spec:
  selector:
    matchLabels:
      app: nginx # has to match .spec.template.metadata.labels
  serviceName: "nginx"
  replicas: 3 # by default is 1
  template:
    metadata:
      labels:
        app: nginx # has to match .spec.selector.matchLabels
    spec:
      terminationGracePeriodSeconds: 10 # send SIGTERM > sleep 10 > send SIGKILL
      containers:
      - name: nginx
        image: k8s.gcr.io/nginx-slim:0.8
        ports:
        - containerPort: 80
          name: web
        volumeMounts:
        - name: www
          mountPath: /usr/share/nginx/html
  volumeClaimTemplates:
  - metadata:
      name: www
    spec:
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 1Gi

rs.md

A StatefulSet using 3 replicas

$ kubectl get pods
NAME                          READY   STATUS    RESTARTS   AGE
web-0                         1/1     Running   0          3m
web-1                         1/1     Running   0          2m
web-2                         1/1     Running   0          2m


$ kubectl get pv
NAME                                       CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM                         STORAGECLASS   REASON   AGE
pvc-c684e7b4-f2f7-11e8-a73a-42010a9c003e   1Gi        RWO            Delete           Bound    default/www-web-0             standard                3m
pvc-d32f5bd5-f2f7-11e8-a73a-42010a9c003e   1Gi        RWO            Delete           Bound    default/www-web-1             standard                2m
pvc-deff2743-f2f7-11e8-a73a-42010a9c003e   1Gi        RWO            Delete           Bound    default/www-web-2             standard                2m

$ kubectl get pvc
NAME                  STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
www-web-0             Bound    pvc-c684e7b4-f2f7-11e8-a73a-42010a9c003e   1Gi        RWO            standard       3m
www-web-1             Bound    pvc-d32f5bd5-f2f7-11e8-a73a-42010a9c003e   1Gi        RWO            standard       3m
www-web-2             Bound    pvc-deff2743-f2f7-11e8-a73a-42010a9c003e   1Gi        RWO            standard       3m