[BUG] Updating some search backpressure settings crash the cluster

[gaobinlong]

Describe the bug

This issue comes from the forum: https://forum.opensearch.org/t/unable-to-start-opensearch-loop-failed-to-apply-settings-and-rate-must-be-greater-than-zero/20908.

When update the setting search_backpressure.cancellation_burst(deprecated), search_backpressure.search_task.cancellation_burst or search_backpressure.search_shard_task.cancellation_burst to an non-default value, the cluster fails to apply the settings and throws org.opensearch.OpenSearchException: java.lang.IllegalArgumentException: rate must be greater than zero, the cluster gets stuck in it and all operations on the master node fail, even restarting the cluster doesn't work.

Related component

Cluster Manager

To Reproduce

1. Update setting

PUT _cluster/settings
{
  "persistent": {
    "search_backpressure.search_task.cancellation_burst": 11
  }
}

, to avoid making your cluster never come back even after restarting it, you can change persistent to transient.

Expected behavior

Fix the bug.

Additional Details

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Host/Environment (please complete the following information):

• OS: [e.g. iOS]
• Version [e.g. 22]

Additional context
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[jainankitk]

@kaushalmahi12 - Can you look into this? While @gaobinlong already has PR for cancellation_burst setting, let us validate other settings for Search Backpressure and Workload Management

[rajiv-kv]

[Triage - attendees 1 2 3] - @jainankitk / @gaobinlong - Can we add more details/stacktraces around as to why the cluster-manager fails to come back after restart ?

[reta]

@gaobinlong mind please updating the documentation for these settings [1], thank you

[1] https://github.com/opensearch-project/documentation-website/blob/main/_tuning-your-cluster/availability-and-recovery/search-backpressure.md