Interview › Kubernetes, Docker, Helm & Podman
What is a PersistentVolume, a PersistentVolumeClaim, and a StorageClass?
Kubernetes, Docker, Helm & Podman · Basic level
Answer
A PersistentVolume is a cluster storage resource, a PersistentVolumeClaim is a user's request for storage, and a StorageClass defines how storage should be dynamically provisioned. Together they decouple app manifests from the storage backend implementation.
Technical explanation
StorageClass volumeBindingMode matters; WaitForFirstConsumer helps choose storage in the same zone as the scheduled Pod.
ReclaimPolicy controls whether the underlying volume is deleted or retained after the PVC is deleted.
Kubernetes workload controllers encode different lifecycle guarantees: interchangeable replicas, stable identities, node-local agents, or finite tasks.
Storage decisions must align with durability, access mode, zone placement, backup, restore, and failover behavior.
Autoscaling should be designed with metrics, scheduling constraints, PDBs, and node capacity together.
Hands-on example
1. Deploy a workload for this exercise using kubectl apply and a small test image such as nginx, busybox, or a purpose-built app: create a PVC from a StorageClass and inspect the provisioned PV.
2. Inspect ownerReferences, events, Pods, PVCs, PVs, EndpointSlices, and metrics depending on the resource being tested.
3. Create a realistic disruption: delete a Pod, scale replicas, restart a node, fill a queue, or recreate storage attachment in a test environment.
4. Write the runbook entry covering expected behavior, safe rollback, and what alarms should exist.
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