The cluster settings operation lets you check the current settings for your cluster, review default settings, and change settings. When you update a setting using the API, OpenSearch applies it to all nodes in the cluster.
flat_settings | Boolean | Whether to return settings in the flat form, which can improve readability, especially for heavily nested settings. For example, the flat form of `"cluster": { "max_shards_per_node": 500 }` is `"cluster.max_shards_per_node": "500"`.
include_defaults (GET only) | Boolean | Whether to include default settings as part of the response. This parameter is useful for identifying the names and current values of settings you want to update.
cluster_manager_timeout | Time unit | The amount of time to wait for a response from the cluster manager node. Default is `30 seconds`.
timeout (PUT only) | Time unit | The amount of time to wait for a response from the cluster. Default is `30 seconds`.
Not all cluster settings can be updated using the cluster settings API. You will receive the error message `"setting [cluster.some.setting], not dynamically updateable"` when trying to configure these settings through the API.
For more information about transient settings, persistent settings, and precedence, see [OpenSearch configuration]({{site.url}}{{site.baseurl}}/install-and-configure/configuring-opensearch/).