NATS: Allow storage resizing of existing eventing-nats NATS cluster

[Teneroy]

Description: Enhance the Kyma managed eventing-nats NATS cluster to allow resizing of the disk storage for already existing clusters. This feature is crucial as the initial storage sizing may become inadequate over time due to changing usage patterns.

Additional Information:

• Current adjustments to Kubernetes resource requests/limits are possible, but the jetStream.fileStorage.size parameter in the eventing-nats NATS CRD is immutable once set.
• Error message from current implementation:

  $ kubectl apply -f eventing-nats.yaml
  The NATS "eventing-nats" is invalid:
  * spec.jetStream: Invalid value: "object": fileStorage is immutable once it was set
  * spec.jetStream.fileStorage: Invalid value: "object": fileStorage is immutable once it was set
  * spec.jetStream.fileStorage.size: Invalid value: "": fileStorage is immutable once it was set

Acceptance Criteria:

• [ ] Implementation of Resizing Functionality:

  • Modify the eventing-nats NATS Custom Resource Definition (CRD) to allow the jetStream.fileStorage.size parameter to be changed after the initial creation.
  • Ensure that the disk storage can be resized with minimal disruption to running services.

• [ ] Validation and Error Handling:

  • Validate that resizing operations do not interfere with the normal operation of the NATS cluster.
  • Implement error handling to manage scenarios where resizing may fail or be invalid.

• [ ] Documentation:

  • Update the documentation to guide users on how to resize the disk storage for an existing NATS cluster.
  • Include examples and best practices for determining the appropriate storage size and performing the resizing operation.

• [ ] Testing:

  • Develop unit and integration tests to cover the resizing functionality.
  • Conduct performance testing to ensure the resizing operation does not degrade the performance of the NATS cluster.

• [ ] Backward Compatibility:

  • Ensure that existing NATS clusters remain functional and can be resized without needing to be recreated.

[Teneroy]

• NATS wasn't designed to be used without eventing module
• research(we are not sure how can we resize pvcs for NATS)
• we don't know how to implement it properly
• we assume it would require a lot of time and resources to do that, but research might shot otherwise
• we have upper limit for throughput, if they want to use more, we would have to find the solution for this one as well

[github-actions[bot]]

This issue has been automatically marked as stale due to the lack of recent activity. It will soon be closed if no further activity occurs. Thank you for your contributions.

[github-actions[bot]]

This issue has been automatically closed due to the lack of recent activity. /lifecycle rotten