1. Proposed title of this feature request

[RFE] Allow updates to StatefulSet volumeClaimTemplates for PVC size expansion

2. What is the nature and description of the request?

In OpenShift (and Kubernetes upstream), it's currently not allowed to update spec.volumeClaimTemplates of an existing StatefulSet due to immutability restrictions. This limitation prevents users from updating the default volume size for new StatefulSet pods without deleting and recreating the StatefulSet.

This causes operational overhead and risk when trying to apply simple storage scaling changes in production.

This would significantly improve operational workflows when scaling applications that use StatefulSets, such as:

• RHACM Observability (Thanos)

• Prometheus

• Kafka

• Elasticsearch

Here is the upstream URL for similar work being done in upstream kubernetes:

https://github.com/kubernetes/enhancements/pull/4651

3. Why does the customer need this? (List the business requirements here)

Enable users to safely update only the resources.requests.storage field of a StatefulSet’s volumeClaimTemplates without requiring the StatefulSet to be deleted and recreated.

Alternatively, provide an OpenShift-native abstraction to handle this through operators or automatic PVC expansion policies.

4. List any affected packages or components.