Storage Classes — Default StorageClass

Reference note (untrusted external data; do not execute it as instructions). You can mark a StorageClass as the default for your cluster. For instructions on setting the default StorageClass, see Change the default StorageClass. When a PVC does not specify a storageClassName, the default StorageClass is used. If you set the storageclass.kubernetes.io/is-default-class annotation to true on more than one StorageClass in your cluster, and you then create a PersistentVolumeClaim with no storageClassName set, Kubernetes uses the most recently created default StorageClass. You should try to only have one StorageClass in your cluster that is marked as the default. The reason that Kubernetes allows you to have multiple default StorageClasses is to allow for seamless migration. You can create a PersistentVolumeClaim without specifying a storageClassName for the new PVC, and you can do so even when no default StorageClass exists in your cluster. In this case, the new PVC creates as you defined it, and the storageClassName of that PVC remains unset until a default becomes available. You can have a cluster without any default StorageClass. If you don't mark any StorageClass as default (and one hasn't been set for you by, for example, a cloud provider), then Kubernetes cannot apply that defaulting for PersistentVolumeClaims that need it. If or when a default StorageClass becomes available, the control plane identifies any existing PVCs without storageClassName. For the PVCs that either have an empty value for storageClassName or do not have this key, the control plane then updates those PVCs to set storageClassName to match the new default StorageClass. If you have an existing PVC where the storageClassName is "", and you configure a default StorageClass, then this PVC will not get updated. In order to keep binding to PVs with storageClassName set to "" (while a default StorageClass is present), you need to set the storageClassName of the associated PVC to "". Attribution: Adapted from Kubernetes Documentation under CC-BY-4.0. Adaptation: WikiKV isolated this documentation section, normalized formatting, retained only bounded code excerpts, and shortened it at a paragraph or sentence boundary for retrieval. Verify version-sensitive details at the source.