Dynamic provisioning autoscaling test

Kubernetes manifests

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: mysc
provisioner: kubernetes.io/gce-pd
reclaimPolicy: Delete
volumeBindingMode: WaitForFirstConsumer
parameters:
---
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:
  serviceName: "nginx"
  replicas: 4
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      affinity:
        podAntiAffinity:
          requiredDuringSchedulingIgnoredDuringExecution:
          - labelSelector:
              matchExpressions:
              - key: app 
                operator: In
                values:
                - nginx
            topologyKey: kubernetes.io/hostname
      containers:
      - name: nginx
        image: nginx
        ports:
        - containerPort: 80
          name: web 
        volumeMounts:
        - name: www 
          mountPath: /usr/share/nginx/html
  volumeClaimTemplates:
  - metadata:
      name: www 
    spec:
      accessModes: [ "ReadWriteOnce" ]
      storageClassName: mysc
      resources:
        requests:
          storage: 10Gi

Output

$ k get nodes
NAME                                       STATUS   ROLES    AGE   VERSION
gke-cluster-1-default-pool-3a7dec17-ckfp   Ready    <none>   53m   v1.17.15-gke.800
gke-cluster-1-default-pool-3ee48415-s84m   Ready    <none>   53m   v1.17.15-gke.800
gke-cluster-1-default-pool-bd049a27-28nt   Ready    <none>   53m   v1.17.15-gke.800

$ k apply -f statefulset-autoscale-test.yaml
service/nginx created
statefulset.apps/web created

$ k get nodes
NAME                                       STATUS   ROLES    AGE   VERSION
gke-cluster-1-default-pool-3a7dec17-cgr9   Ready    <none>   94s   v1.17.15-gke.800
gke-cluster-1-default-pool-3a7dec17-ckfp   Ready    <none>   77m   v1.17.15-gke.800
gke-cluster-1-default-pool-3ee48415-s84m   Ready    <none>   77m   v1.17.15-gke.800
gke-cluster-1-default-pool-bd049a27-28nt   Ready    <none>   77m   v1.17.15-gke.800

$ k get pods -o wide
NAME       READY   STATUS    RESTARTS   AGE   IP          NODE                                       NOMINATED NODE   READINESS GATES
web-0      1/1     Running   0          21m   10.76.2.4   gke-cluster-1-default-pool-3ee48415-s84m   <none>           <none>
web-1      1/1     Running   0          20m   10.76.0.4   gke-cluster-1-default-pool-bd049a27-28nt   <none>           <none>
web-2      1/1     Running   0          20m   10.76.1.9   gke-cluster-1-default-pool-3a7dec17-ckfp   <none>           <none>
web-3      1/1     Running   0          20m   10.76.3.2   gke-cluster-1-default-pool-3a7dec17-cgr9   <none>           <none>

$ k get pvc
NAME        STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
www-web-0   Bound    pvc-5f6fd0d0-198d-4d05-87f3-9cce7a4ac990   10Gi       RWO            mysc           23m
www-web-1   Bound    pvc-522116c1-3ee7-4f52-8181-1cafb75d555b   10Gi       RWO            mysc           22m
www-web-2   Bound    pvc-b6b0af29-7cd7-4a31-bece-40a3d881097c   10Gi       RWO            mysc           21m
www-web-3   Bound    pvc-10e1af63-d362-4f80-9005-8bc0ad00491b   10Gi       RWO            mysc           21m

$ k get sc
NAME                 PROVISIONER            RECLAIMPOLICY   VOLUMEBINDINGMODE      ALLOWVOLUMEEXPANSION   AGE
mysc                 kubernetes.io/gce-pd   Delete          WaitForFirstConsumer   false                  46m
standard (default)   kubernetes.io/gce-pd   Delete          Immediate              true                   97m