A StorageClass names a category of persistent storage available in a Kubernetes cluster. It specifies a provisioner and parameters for creating volumes in that category. When an application needs persistent storage, it requests a PersistentVolumeClaim (PVC), which can name a StorageClass; the pod then uses the claim rather than referring directly to a PersistentVolume. section 10.2.5 section 10.1.1
Choose a class for a claim
Run `kubectl get sc` to see available classes and identify one marked `(default)`. A PVC can request a specific class with `spec.storageClassName: premium-rwo`, alongside its storage request and access mode. If the field is omitted, the cluster uses its default class, if one exists. A claim naming a nonexistent class stays Pending; `kubectl describe` on the claim shows repeated ProvisioningFailed events. section 10.2.1
$ kubectl get sc standard-rwo -o yaml #1
allowVolumeExpansion: true
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
annotations:
components.gke.io/component-name: pdcsi
components.gke.io/component-version: 0.21.32
components.gke.io/layer: addon
storageclass.kubernetes.io/is-default-class: "true" #2
creationTimestamp: "2025-07-07T07:31:57Z"
labels:
addonmanager.kubernetes.io/mode: EnsureExists
k8s-app: gcp-compute-persistent-disk-csi-driver
name: standard-rwo
resourceVersion: "1751873517609007007"
uid: 6a6a1c0c-48e7-4c10-ab3c-63ad23e0a9a3
parameters: #3
type: pd-balanced #3
provisioner: pd.csi.storage.gke.io #4
reclaimPolicy: Delete #5
volumeBindingMode: WaitForFirstConsumer #6
The inspected `standard-rwo` class shows the provisioner, a parameter passed to it, the default-class annotation, a reclaim policy, and a volume binding mode. section 10.2.5
The binding mode determines when a volume is provisioned and bound to its claim. `Immediate` does this when the PVC is created. `WaitForFirstConsumer` waits for a pod that uses the claim. Classes can also differ in storage technology and supported access modes, such as ReadWriteOnce and ReadWriteMany. section 10.2.5
Represent a manually provided local volume
A local class can use `provisioner: kubernetes.io/no-provisioner` because its storage is provided manually, not dynamically created. Set `volumeBindingMode: WaitForFirstConsumer` so binding waits until the pod is scheduled. Create a separate local PersistentVolume that names this class and identifies the node and path holding the storage. section 10.3.1
