Persistent Volumes and Claims: Stateful Storage
Kubernetes excels at managing stateless applications, but production reality demands stateful workloads—databases, message queues, file storage systems. PersistentVolumes (PV) and PersistentVolumeClaims (PVC) provide the abstraction layer that makes stateful storage portable, durable, and manageable across cluster infrastructure. For the CKA exam, mastering storage represents 10% of your score and is essential for real-world Kubernetes administration.
The storage model in Kubernetes separates provisioning (administrator responsibility via PV) from consumption (developer responsibility via PVC). This decoupling enables platform teams to standardize storage offerings through StorageClasses while application teams request storage without infrastructure knowledge. Understanding the PV lifecycle—binding, mounting, releasing, and reclaiming—is critical for both exam success and production troubleshooting.
Modern Kubernetes storage leverages the Container Storage Interface (CSI), which replaced legacy in-tree volume plugins. CSI drivers from AWS, Google Cloud, Azure, NetApp, and others provide production-grade dynamic provisioning. The 2025 Kubernetes landscape includes ReadWriteOncePod access mode (v1.29+), enhanced volume expansion capabilities, and topology-aware scheduling via WaitForFirstConsumer binding mode.