local-path-provisioner

 

The local-path-provisioner is a persistent volume provisioner dedicated for a kind based kubernetes cluster. Using it both simplifies helm charts and provides a better compatibility with EKS gp2 and gp3 storage clasess. In this post we will see how to use it.

Working Without a Provisioner

In case we don't have a provisioner we need to manually handle the persistent volume creation as part of the helm chart. This can be done using a new dedicated storage class for our kind development cluster. For example:

{{- if eq .Values.data.storageClass "development-storage" }}
apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv-1
  labels:
    type: local
spec:
  storageClassName: development-storage-class
  capacity:
    storage: 10G
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: "/mnt/hostpath/data"
{{- end }}

Then we need to specify this storage class as part of the persistent volume claim:

  volumeClaimTemplates:
    - metadata:
        name: my-pvc
      spec:
        accessModes: [ "ReadWriteOnce" ]
        storageClassName: "development-storage-class"
        resources:
          requests:
            storage: 10G

Using The Local-Path-Provisioner

To use the local-path-provisioner we install it:

kubectl apply -f https://raw.githubusercontent.com/rancher/local-path-provisioner/master/deploy/local-path-storage.yaml

And then all we need it to specify local-path as the storage class, for example:

  volumeClaimTemplates:
    - metadata:
        name: my-pvc
      spec:
        accessModes: [ "ReadWriteOnce" ]
        storageClassName: "local-path"
        resources:
          requests:
            storage: 10G

We not only gain this simpler helm chart, but also permissions respectful provisioner. This simplifies life for pods that use modified security context such as grafana and clickhouse:

      securityContext:
        runAsUser: 50001
        runAsGroup: 50001
        fsGroup: 50001
        fsGroupChangePolicy: OnRootMismatch

Final Note

Actually, I guess I've got used to using the old method without the local-path-provisioner that I took it as is. Now that I know the local-path-provisioner, I think to myself, well why the complexity, I should have known it earlier.