Issue with Changing ZooKeeper StorageClass in Strimzi Kafka Helm Chart

[apolienko]

Issue with Changing ZooKeeper StorageClass in Strimzi Kafka Helm Chart

Environment

• Strimzi Kafka installed via Helm chart
• Current configuration: 3-node ZooKeeper cluster

What I'm Trying to Achieve

I want to change the StorageClass used by ZooKeeper PVCs from standard-rwo-retain to the default StorageClass without losing data or disrupting the cluster.

Steps Taken

1. I removed the storageClass line from values.yaml:

zookeeper:
  storageDeleteClaim: true
  # storageClass: standard-rwo-retain  <- removed this line
  replicas: 3
  resources:

2. Applied the changes with Helm, and the output confirmed the removal:

storage:
  type: persistent-claim
- class: "standard-rwo-retain"
  size: "20Gi"
  deleteClaim: true

Current Problem

After applying these changes, I've verified that the storageClass specification is no longer present in the Kafka custom resource. However, the ZooKeeper pods are still using the old PVCs with the previous StorageClass. No new PVCs were created with the default StorageClass.

Main Question

How can I properly perform maintenance on the ZooKeeper cluster to change the StorageClass?

Specifically, I want to achieve a rolling update that would:

1. Replace all PVCs and PVs in the ZooKeeper pods
2. Use the new default StorageClass (or any other class)
3. Preserve all data across the cluster
4. Maintain cluster stability during the transition (no downtime)

What is the correct procedure to make this change safely in a production environment with a 3-node ZooKeeper cluster?

[kyguy]

Hi @apolienko , from what I understand there is no standard/recommended approach on how to do this for Zookeeper PVs. Checkout the post here for more information [1]

For ZooKeeper, none of these are really possibly. There are only hacky ways how to change the storage type. But maybe you can use the KRaft-migration that you would anyway need to go through sooner or later as an opportunity to change the storage type.

[1] https://stackoverflow.com/questions/79181645/how-to-change-pv-storageclass-of-strimzi-kafka-cluster