According to the VMware Cloud Foundation 9.0.4 Architecture and Design Guide, vSphere Pods (which support VMware Kubernetes Service or VKS clusters) use three types of storage: ephemeral VMDKs, persistent volume VMDKs, and container image VMDKs.
The document explicitly states:
> “A vSphere Pod requires ephemeral storage to store such Kubernetes objects as logs, emptyDir volumes, and ConfigMaps during its operations. This ephemeral, or transient, storage lasts as long as the pod continues to exist.”
Ephemeral storage is non-persistent by design and is deleted once the pod lifecycle ends. It provides temporary space for data that doesn’t need to persist beyond the pod’s lifespan, such as application logs, temporary caches, or transient compute data. This aligns with Kubernetes’ ephemeral storage model integrated into vSphere infrastructure.
Persistent workloads, by contrast, utilize storage policies and vSphere CNS-backed persistent volumes. Therefore, ephemeral storage is the correct type for non-persistent pod data.
References (VMware Cloud Foundation documents):
VMware Cloud Foundation 9.0.4 — “Storage Policies for a Supervisor” (p. 5632–5633)
VMware Cloud Foundation 9.0.4 — “vSphere Pod Storage Types: Ephemeral, Persistent, and Container Image VMDKs.”
---
