OpenSearch configuration

Most OpenSearch configuration can take place in the cluster settings API. Certain operations require you to modify opensearch.yml and restart the cluster.

Whenever possible, use the cluster settings API instead; opensearch.yml is local to each node, whereas the API applies the setting to all nodes in the cluster. Certain settings, however, require opensearch.yml. In general, these settings relate to networking, cluster formation, and the local file system. To learn more, see Cluster formation.

Update cluster settings using the API

The first step in changing a setting is to view the current settings:

GET _cluster/settings?include_defaults=true

For a more concise summary of non-default settings:

GET _cluster/settings

Three categories of setting exist in the cluster settings API: persistent, transient, and default. Persistent settings, well, persist after a cluster restart. After a restart, OpenSearch clears transient settings.

If you specify the same setting in multiple places, OpenSearch uses the following precedence:

1. Transient settings
2. Persistent settings
3. Settings from opensearch.yml
4. Default settings

To change a setting, just specify the new one as either persistent or transient. This example shows the flat settings form:

PUT _cluster/settings
{
  "persistent" : {
    "action.auto_create_index" : false
  }
}

You can also use the expanded form, which lets you copy and paste from the GET response and change existing values:

PUT _cluster/settings
{
  "persistent": {
    "action": {
      "auto_create_index": false
    }
  }
}

Configuration file

You can find opensearch.yml in /usr/share/opensearch/config/opensearch.yml (Docker) or /etc/opensearch/opensearch.yml (most Linux distributions) on each node.

The demo configuration includes a number of settings for the security plugin that you should modify before using OpenSearch for a production workload. To learn more, see Security.