TheVMware Cloud Foundation 9.0 and vSphere with Tanzu documentationdescribes the Container Storage Interface (CSI) as follows:

“The vSphere CSI driver allows vSphere storage to be exposed as persistent storage to containerized applications running on Kubernetes clusters. The driver implements the Kubernetes CSI specification and enables dynamic provisioning, attach/detach, and snapshot operations for persistent volumes.”

Key points from the documentation:

CSI is not limited tovSphere object storage(A). It works with vSAN, VMFS, NFS, and other vSphere-supported datastores.

Its purpose is to providepersistent storage(B), so containerized workloads have data that outlives pod lifecycles.

CSI is not restricted to “cloud native storage only” (C); it is the standard interface for Kubernetes persistent storage.

CSI is not used forephemeral storage(D); ephemeral storage is provided by local container runtimes and does not require CSI.

Therefore, the correct description is that CSI is aplug-in that allows providers to expose storage as persistent storageto Kubernetes workloads running in vSphere Supervisor clusters.