kube-single-age/clusters/base/infra/storage-class-longhorn-retain/storageclass.yaml

apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: longhorn-retain
  annotations:
    storageclass.kubernetes.io/is-default-class: "true"
provisioner: driver.longhorn.io
reclaimPolicy: Retain
allowVolumeExpansion: true
parameters:
  numberOfReplicas: "3"
  staleReplicaTimeout: "30"