I'm newbie in the Kubernetes world and I try to figure it out how a volumeClaim or volumeClaimTemplates defined in a StatefulSet can be linked to a specific PersistentVolume.

I've followed some tutorials to understand and set a local PersistentVolume. If I take Elasticsearch as an example, when the StatefulSet starts, the PersistantVolumeClaim is bound to the PersistantVolume.

Like you know, for a local PersistentVolume we must define the local path to the storage destination.

For Elasticsearch I've defined something like this

local:
  path: /mnt/kube_data/elasticsearch

But in a real project, there are more than one persistent volume. So, I will have more than one folder in path /mnt/kube_data. How does Kubernetes select the right persistent volume for a persistent volume claim?

I don't want Kubernetes to put Database data in a persistent volume created for another service.

Here is the configuration for Elasticsearch :

---
apiVersion: apps/v1beta1
kind: StatefulSet
metadata:
  name: elasticsearch-sts
spec:
  serviceName: elasticsearch
  replicas: 1
[...]
    containers:
    - name: elasticsearch
        image: docker.elastic.co/elasticsearch/elasticsearch:6.4.2
        volumeMounts:
        - name: elasticsearch-data
        mountPath: /usr/share/elasticsearch/data
volumeClaimTemplates:
- metadata:
    name: elasticsearch-data
  spec:
    accessModes: [ "ReadWriteOnce" ]
    storageClassName: local-storage
    resources:
        requests:
        storage: 10Gi
---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv-elasticsearch
spec:
  capacity:
    storage: 10Gi
accessModes:
- ReadWriteOnce
persistentVolumeReclaimPolicy: Retain
storageClassName: local-storage
local:
    path: /mnt/elasticsearch
nodeAffinity:
    required:
    nodeSelectorTerms:
    - matchExpressions:
        - key: node-role.kubernetes.io/master
        operator: Exists
---