AKS Storage and Persistence

Containers are ephemeral by design — when a pod restarts, any data stored in the container filesystem is lost. For stateful workloads like databases, message queues, and file storage, you need persistent volumes that survive pod restarts, rescheduling, and even node failures. This lesson covers how AKS handles storage through Kubernetes persistent volumes, Azure Disk, Azure Files, and CSI drivers.

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The Kubernetes Storage Model

Kubernetes abstracts storage through three key objects:

+-------------------+       +--------------------------+       +------------------+
| PersistentVolume  | <---- | PersistentVolumeClaim    | <---- |      Pod         |
| (PV)              |       | (PVC)                    |       |                  |
| The actual storage|       | A request for storage    |       | Mounts the PVC   |
+-------------------+       +--------------------------+       +------------------+

PersistentVolume (PV)

A PV represents a piece of storage in the cluster — an Azure Disk, an Azure Files share, or an NFS mount. PVs have a lifecycle independent of any pod.

PersistentVolumeClaim (PVC)

A PVC is a request for storage by a user. It specifies the size, access mode, and storage class. Kubernetes binds the PVC to an available PV (or dynamically provisions one).

StorageClass