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Jeroen Jacobs
Asked: 2017-06-03 05:23:30 +0800 CST

kubernetes and sharing an nfs volume accross multiple pods

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I'm trying to figure out how I can use a single nfs share with k8s persistent volume claims.

For example, let's say I have a single nfs pv configured:

apiVersion: v1
kind: PersistentVolume
metadata:
  name: nfs-pv
spec:
  capacity:
    storage: 10Gi
  accessModes:
    - ReadWriteMany
  persistentVolumeReclaimPolicy: Retain
  storageClassName: nfs-storage
  nfs:
    path: /var/nfs_exports
    server: 10.9.0.205
    readOnly: false

Is it possible to create multiple volume claims that map to subdirectories within this single share?

For example again, let's say I create the following volume claims:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: influx-data
  namespace: kube-system
spec:
  storageClassName: nfs-storage
  accessModes:
  - ReadWriteMany
  resources:
     requests:
       storage: 5Gi
---

and:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: elasticsearch-data
  namespace: kube-system
spec:
  storageClassName: nfs-storage
  accessModes:
  - ReadWriteMany
  resources:
     requests:
       storage: 2Gi
---

I guess, that both claims will be bound to the pv, but there is no way to seperate the data of both elasticsearch and influxdb.

I hope you understand what I'm trying to do here (sorry, I find it difficult to explain). I just want to use a single nfs share that can be used by multiple pods, while still keeping their data seperate.

nfs

2 Answers

  1. In this case (sharing one PV using two PVCs in two different folders ), you may use the subPath option in the configuration of the volumeMounts of your containers:

    [...]
'spec': {
  'template': {
    'metadata': {'name': 'container_name'},
      'spec': {
        'restartPolicy': 'Never',
        'containers':[{
          'image': 'busybox',
          'name': 'example',
          'command': ['/bin/ash'],
          'args': ['-c', ls -l /data],
          'volumeMounts': [{
            'name': 'influx-vol-mount',
            'mountPath': '/data',
            'subPath': 'subpath_1',
            'readOnly': False
         },
         { 'name': 'es-vol-mount',
            'mountPath': '/data',
            'subPath': 'subpath_2',
            'readOnly': False
      }]
  }],
  'volumes': [
    {
    'name': 'influx-vol-mount',
    'persistentVolumeClaim': {'claimName': 'influx-data'}
    }, 
    {
    'name': 'store-vol',
    'persistentVolumeClaim': {'claimName': 'elasticsearch-data'}
    }
  ]
}
[...]
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