StarRocksCluster Configuration Error: Unable to Mount emptyDir Volume at /tmp Path Without Specifying storageSize.

[kapilsingh421]

Describe the bug

When attempting to mount an emptyDir volume with a mount path of /tmp in a StarRocksCluster environment, the system does not seem to recognize or support this configuration. Instead, it appears to only support Persistent Volumes (PV). The configuration used is as follows:

- name: {{ .Values.starrocksFESpec.storageSpec.name }}-tmp
  mountPath: /tmp

After encountering issues with this setup, I deleted the Custom Resource (CR) and reapplied it, which led to the following error message:

StarRocksCluster.starrocks.com "kube-starrocks" is invalid: spec.starRocksFeSpec.storageVolumes[2].storageSize: Required value

This error suggests that a storageSize must be provided, indicating a reliance on Persistent Volumes. However, the requirement is to use emptyDir for the /tmp path.

To Reproduce

1. Define a volume mount in the StarRocksCluster configuration to use an emptyDir with a mount path of /tmp.
2. Apply the configuration to the cluster.
3. Observe that the system either does not recognize the configuration or throws an error requiring a storageSize to be specified, which is indicative of Persistent Volume usage, not emptyDir.**

Expected behavior

The expected behavior is for the StarRocksCluster to successfully mount an emptyDir volume at the /tmp path without requiring the specification of a storageSize. This would allow for temporary file storage that is not persistent across pod restarts.

Version

• Operator Version: [ latest]
• Chart Name: [kube-starrocks]

[kevincai]

thanks! will take a look how to support this ability.

[yandongxiao]

storageVolumes:
    - name: fedata-main
      storageSize: 15Gi
      mountPath: /opt/starrocks/fe
    - name: fedata-meta
      storageSize: 15Gi
      mountPath: /opt/starrocks/fe/meta
    - name: tmp-data
      mountPath: /tmp

Due to the limitation of StorageSize, it is indeed not supported to configure in this way (for tmp-data). Moreover, from the above semantics, it should create a PVC using the Default storage class, not an EmptyDir.

The implementation logic of the Operator is: for each configured item, a corresponding persistent volume will be created. If not configured, meta, log, an emptyDir will be configured under statefulset.spec.template.volumes.

[yandongxiao]

In Kubernetes, PersistentVolumeClaim (PVC) and emptyDir are two different types of volumes, and they cannot be used interchangeably. PVC is used to request storage resources and mount them into a Pod, while emptyDir is a temporary directory created after a Pod is assigned to a node.

[yandongxiao]

Based on the scenario you described, I think emptyDir is still the best choice. We can consider supporting emptyDir and hostPath.

[kapilsingh421]

Hello @yandongxiao

I've encountered an issue where our /tmp directory is currently not writable. I'm considering the use of a Persistent Volume (PV) for the frontend /tmp directory to resolve this.

Could you please advise if utilizing a PV for this purpose is a suitable solution? Additionally, if this approach is recommended, what would be the ideal storage size for the PV in this context?

or

Alternatively, is there an option to define a custom location for the temporary directory, such as /opt/starrocks/fe/tmp?"

[kapilsingh421]

ok that's great but do you have an ETA for supporting emptyDir ?

[yandongxiao]

Maybe Pull Request (PR) can be able to be merged this week. You may need to build the container image from the main branch yourself, but it's very simple.

[kapilsingh421]

yeah that's great no Problem I will build this image

[yandongxiao]

#324
You can try to use this PR

[kapilsingh421]

Thanks working