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.
master_timeout | Time | The amount of time to wait for a response from the master node. Default is 30 seconds.
timeout (PUT only) | Time | The amount of time to wait for a response from the cluster. Default is 30 seconds.
## Request body
The GET operation has no request body options.
For a PUT operation, the request body must contain `transient` or `persistent`, along with the setting you want to update:
For more information about transient settings, persistent settings, and precedence, see [OpenSearch configuration]({{site.url}}{{site.baseurl}}/opensearch/configuration/).