[helm] Add tabletServer.count configuration option

[morazow]

Purpose

Linked issue: close #2455

Brief change log

Enable setting the number tablet servers when deploying with helm charts.

Tests

API and Format

Documentation

Added parameter section in the helm deployment documentation.

[affo]

Thanks for your contribution, suggesting a more general way of treating tablet server's conf

[affo]

Just a suggestion, it looks to me that persistence is also a tablet server configuration.

Wouldn't it be better to have:

tablet:
  numberOfReplicas:
  storage:
    enabled:
    size:
    class:

[affo]

@swuferhong what do you think?

[swuferhong]

what means 'persistence' for fluss?

[morazow]

Hello @swuferhong,

In the tablet and coordinator servers we have option to enabled and attach persistent volume (PV), so that the storage is not transient when they are recreated.

For example, for tablet: https://github.com/morazow/fluss/blob/main/helm/templates/sts-tablet.yaml#L99-L109

This could be enabled for data volumes.

I agree with @affo, we should maybe separate these configurations per type since sizes and storage classes could be different for coordinator and tablet.

[affo]

@swuferhong persistence is the current key in values.yaml:

persistence:
  enabled: false
  size: 1Gi
  storageClass:

And it is a top-level key.

What I am suggesting here is to group multiple tablet-relevant configs under tablet.
In any case we would need:

tablet:
  numberOfReplicas:

coordinator:
  numberOfReplicas: # for HA

At this point, we may extend tablet to include the current persistence values.
Does this make sense to you?

[morazow]

Updated with numberOfReplicas suggestion, let's wait for @swuferhong input for moving persistence to each tablet & coordinator sections 🤝

[affo]

This looks like a flakey test: https://github.com/apache/fluss/actions/runs/21281906620/job/61447896522?pr=2456

[swuferhong]

LGTM

[affo]

That's great, this also adds separate configurations for storage for the coordinator, which definitely makes sense.

Truth be told, the coordinator does not need any storage as of now 🤝
Will probably need after Zookeeper removal.

Anyhow, the charts are generic enough, and storage for the coordinator is disabled by default.