NFS Persisent Volume Config and Setup

September 28, 2022

This tutorials is useful for Kubernetes storage architecture and concepts. Specifically, this focuses on NFS. Running kubernetes On-Prem has its challenges. One of the challenges centers on using Persistent Volumes. While options exists like Gluster, Ceph etc. NFS works pretty well. It’s easy to setup and accomplishes a lot with minimal effort relative to the others. See my previous post on NFS Setup before continuing with this tutorial.

Connecting to NFS directly with Pod manifest

To connect to the NFS volume directly with Pod manifest, use the NFSVolumeSource in the Pod. Here is an example:

---
apiVersion: v1
kind: Pod
metadata:
  name: test-nfs-pod
  labels:
    app.kubernetes.io/name: alpine
    app.kubernetes.io/part-of: kubernetes-complete-reference
spec:
  containers:
  - name: alpine
    image: alpine:latest
    command:
      - touch
      - /data/test
    volumeMounts:
    - name: nfs-volume
      mountPath: /data
  volumes:
  - name: nfs-volume
    nfs:
      server: 192.168.1.50
      path: /data
      readOnly: no

Connecting using the PersistentVolume resource:

To create the PersistentVolume object for the NFS volume, use the following manifest.

---
apiVersion: v1
kind: PersistentVolume
metadata:
  name: nfs-volume
  labels:
    storage.k8s.io/name: nfs
    storage.k8s.io/part-of: kubernetes-complete-reference
spec:
  accessModes:
  - ReadWriteOnce
  - ReadOnlyMany
  - ReadWriteMany
  capacity:
    storage: 4Gi
  storageClassName: ""
  persistentVolumeReclaimPolicy: Recycle
  volumeMode: Filesystem
  nfs:
    server: 192.168.1.50 
    path: /data
    readOnly: no

Dynamic provisioning using StorageClass:

To provision PersistentVolume dynamically using the StorageClass, you need to install the NFS provisioner. The nfs-subdir-external-provisioner achieves that. Install with command below.

helm repo add nfs-subdir-external-provisioner https://kubernetes-sigs.github.io/nfs-subdir-external-provisioner

helm install nfs-subdir-external-provisioner nfs-subdir-external-provisioner/nfs-subdir-external-provisioner \
  --create-namespace \
  --namespace nfs-provisioner \
  --set nfs.server=192.168.1.50 \
  --set nfs.path=/data

To create the PersistentVolumeClaim use the following manifest:

---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: nfs-test
  labels:
    storage.k8s.io/name: nfs
    storage.k8s.io/part-of: kubernetes-complete-reference
spec:
  accessModes:
  - ReadWriteMany
  storageClassName: nfs-client
  resources:
    requests:
      storage: 5Gi

Reference Links

• https://itnext.io/kubernetes-storage-part-1-nfs-complete-tutorial-75e6ac2a1f77
• https://fabianlee.org/2022/01/12/kubernetes-nfs-mount-using-dynamic-volume-and-storage-class/
• https://medium.com/@myte/kubernetes-nfs-and-dynamic-nfs-provisioning-97e2afb8b4a9
• https://github.com/kubernetes-sigs/nfs-subdir-external-provisioner