Demo Dynamic Provisioning

We’ll step back and look at how storage works from a Kubernetes perspective (the same concepts apply in OpenShift). Kubernetes uses a plugin architecture called the Container Storage Interface (CSI) to allow the cluster to talk to external storage providers such as Azure Storage (Disks/Files), AWS (EBS/EFS), NetApp, and others. As long as a vendor provides a CSI driver, Kubernetes can provision and attach storage through that driver. The CSI spec: https://kubernetes.io/docs/concepts/storage/container-storage-interface/

How it works conceptually

The CSI driver is the plugin that actually talks to the external storage backend.
A StorageClass is a Kubernetes object that describes provisioning behavior and references the CSI provisioner.
PersistentVolumes (PVs) represent actual storage resources. PVs may be created statically by an administrator or dynamically by a StorageClass/provisioner.
PersistentVolumeClaims (PVCs) are requests for storage from pods. A PVC specifies size, access modes, and optionally a StorageClass. When dynamic provisioning is enabled, the StorageClass/provisioner creates a PV that satisfies the PVC.

Quick provisioning paths

Dynamic provisioning: PVC → StorageClass → CSI provisioner → provision storage → create PV → bind to PVC.
Static provisioning: Admin creates PV → PVC binds to existing PV.

The term “persistent storage” in OpenShift maps directly to Kubernetes PersistentVolumes. The StorageClass, PersistentVolume, and PersistentVolumeClaim objects behave the same in both platforms.

Kubernetes storage objects (at-a-glance)

Resource Type	Purpose	Example / Command
StorageClass	Describes how to provision storage and references a CSI provisioner	See `storage.k8s.io/v1` StorageClass in the YAML below
PersistentVolume (PV)	A piece of storage in the cluster (static or dynamically created)	Admin-created PV or provisioned by StorageClass
PersistentVolumeClaim (PVC)	Request for storage by a pod	`kubectl apply -f pvc.yaml`
Pod / Deployment	Consumes a PVC and mounts the volume into containers	`volumeMounts` + `volumes` in Pod/Deployment spec

Example: StorageClass + PVC + Deployment using Azure Files CSI

The StorageClass references the Azure Files CSI provisioner (file.csi.azure.com) and sets mount options and parameters (for example, SKU).
The PVC requests storage from that StorageClass.
The Deployment mounts the resulting volume into nginx containers.

# StorageClass using the Azure Files CSI driver
kind: StorageClass
apiVersion: storage.k8s.io/v1
metadata:
  name: azurefile-csi
provisioner: file.csi.azure.com
allowVolumeExpansion: true
mountOptions:
  - dir_mode=0777
  - file_mode=0777
  - uid=0
  - gid=0
  - mfsymlinks
  - cache=strict
  - actimeo=30
parameters:
  skuName: Premium_LRS
---
# PersistentVolumeClaim that requests 10Gi from the azurefile-csi StorageClass
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: azurefile
spec:
  accessModes:
    - ReadWriteMany
  storageClassName: azurefile-csi
  resources:
    requests:
      storage: 10Gi
---
# Deployment that mounts the PVC into containers
apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginxdeployment
spec:
  selector:
    matchLabels:
      app: nginxdeployment
  replicas: 2
  template:
    metadata:
      labels:
        app: nginxdeployment
    spec:
      containers:
      - name: nginx
        image: nginx:latest
        volumeMounts:
        - name: azure
          mountPath: /mnt/azure
      volumes:
      - name: azure
        persistentVolumeClaim:
          claimName: azurefile

Manifest explanation (component-by-component)

StorageClass (azurefile-csi)
- provisioner: file.csi.azure.com points to the Azure Files CSI driver.
- allowVolumeExpansion: true enables resizing the volume after provisioning.
- mountOptions and parameters such as skuName: Premium_LRS control how the Azure Files share is created and mounted.
PersistentVolumeClaim (azurefile)
- Requests 10Gi with ReadWriteMany access and explicitly references the azurefile-csi StorageClass.
- When the PVC is created, the StorageClass/provisioner dynamically provisions a backing PV and binds it to the PVC.
Deployment (nginxdeployment)
- Mounts the bound PVC at /mnt/azure in each nginx pod using volumeMounts and volumes.
- The claimName must match the PVC name.

Resources and further reading

Kubernetes Container Storage Interface (CSI): https://kubernetes.io/docs/concepts/storage/container-storage-interface/
StorageClass docs: https://kubernetes.io/docs/concepts/storage/storage-classes/
PersistentVolume and PersistentVolumeClaim: https://kubernetes.io/docs/concepts/storage/persistent-volumes/

This dynamic provisioning flow is identical in OpenShift: the cluster uses a StorageClass to talk to a CSI provisioner, which provisions storage and returns a PersistentVolume that satisfies the PersistentVolumeClaim — your pods then mount that volume.

Introduction

Pre-Requisite – Docker and Kubernetes

Getting Started with OpenShift

OpenShift Concepts – Projects and Users

Concepts – Builds and Deployments

Networks, Services, Routes and Scaling

Storage, Templates and Catalog

OpenShift Security

Conclusion and APPENDIX

Demo Dynamic Provisioning

Watch Video