Add doc for dynamic threadpool settings (opensearch-project#8588)

* Add doc for dynamic threadpool settings

Signed-off-by: Gaurav Bafna <[email protected]>

* Address comments

Signed-off-by: Gaurav Bafna <[email protected]>

* Update _install-and-configure/configuring-opensearch/index-settings.md

Co-authored-by: kolchfa-aws <[email protected]>
Signed-off-by: Gaurav Bafna <[email protected]>

* Update _install-and-configure/configuring-opensearch/index-settings.md

Co-authored-by: kolchfa-aws <[email protected]>
Signed-off-by: Gaurav Bafna <[email protected]>

* Update _install-and-configure/configuring-opensearch/index-settings.md

Co-authored-by: kolchfa-aws <[email protected]>
Signed-off-by: Gaurav Bafna <[email protected]>

* Update _install-and-configure/configuring-opensearch/index-settings.md

Co-authored-by: kolchfa-aws <[email protected]>
Signed-off-by: Gaurav Bafna <[email protected]>

* Update _install-and-configure/configuring-opensearch/index-settings.md

Co-authored-by: kolchfa-aws <[email protected]>
Signed-off-by: Gaurav Bafna <[email protected]>

* Update _install-and-configure/configuring-opensearch/index-settings.md

Co-authored-by: kolchfa-aws <[email protected]>
Signed-off-by: Gaurav Bafna <[email protected]>

* Apply suggestions from code review

Co-authored-by: Nathan Bower <[email protected]>
Signed-off-by: kolchfa-aws <[email protected]>

---------

Signed-off-by: Gaurav Bafna <[email protected]>
Signed-off-by: Gaurav Bafna <[email protected]>
Signed-off-by: kolchfa-aws <[email protected]>
Co-authored-by: kolchfa-aws <[email protected]>
Co-authored-by: Nathan Bower <[email protected]>

Author: 3 people

_install-and-configure/configuring-opensearch/index-settings.md

@@ -81,6 +81,16 @@ OpenSearch supports the following dynamic cluster-level index settings:
 
 - `cluster.default_number_of_replicas` (Integer): Controls the default number of replicas for indexes in the cluster. The index-level `index.number_of_replicas` setting defaults to this value if not configured. Default is `1`.
 
+- `cluster.thread_pool.<fixed-threadpool>.size` (Integer): Controls the sizes of both the fixed and resizable queue thread pools. Overrides the defaults provided in `opensearch.yml`.
+
+- `cluster.thread_pool.<scaling-threadpool>.max` (Integer): Sets the maximum size of the scaling thread pool. Overrides the default provided in `opensearch.yml`.
+
+- `cluster.thread_pool.<scaling-threadpool>.core` (Integer): Specifies the core size of the scaling thread pool. Overrides the default provided in `opensearch.yml`.
+
+
+Before tuning thread pool settings dynamically, note that these are expert-level settings that can potentially destabilize your cluster. Modifying thread pool settings applies the same thread pool size to all nodes, so it's not recommended for clusters with different hardware for the same roles. Similarly, avoid tuning thread pools shared by both data nodes and cluster manager nodes. After making these changes, we recommend monitoring your cluster to ensure that it remains stable and performs as expected.
+{: .warning}
+
 ## Index-level index settings
 
 You can specify index settings at index creation. There are two types of index settings: