opensearch-docs-cn/_api-reference/cluster-api/cluster-awareness.md

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Cluster routing and awareness

Introduced 1.0 {: .label .label-purple }

To control the distribution of search or HTTP traffic, you can use the weights per awareness attribute to control the distribution of search or HTTP traffic across zones. This is commonly used for zonal deployments, heterogeneous instances, and routing traffic away from zones during zonal failure.

Path and HTTP methods

PUT /_cluster/routing/awareness/<attribute>/weights
GET /_cluster/routing/awareness/<attribute>/weights?local
GET /_cluster/routing/awareness/<attribute>/weights

Path parameters

Parameter	Type	Description
attribute	String	The name of the awareness attribute, usually zone. The attribute name must match the values listed in the request body when assigning weights to zones.

Request body parameters

Parameter	Type	Description
weights	JSON object	Assigns weights to attributes within the request body of the PUT request. Weights can be set in any ratio, for example, 2:3:5. In a 2:3:5 ratio with 3 zones, for every 100 requests sent to the cluster, each zone would receive either 20, 30, or 50 search requests in a random order. When assigned a weight of 0, the zone does not receive any search traffic.
_version	String	Implements optimistic concurrency control (OCC) through versioning. The parameter uses simple versioning, such as 1, and increments upward based on each subsequent modification. This allows any servers from which a request originates to validate whether or not a zone has been modified.

In the following example request body, zone_1 and zone_2 receive 50 requests each, whereas zone_3 is prevented from receiving requests:

{ 
      "weights":
      {
        "zone_1": "5", 
        "zone_2": "5", 
        "zone_3": "0"
      }
      "_version" : 1
}

Example: Weighted round robin search

The following example request creates a round robin shard allocation for search traffic by using an undefined ratio:

Request

PUT /_cluster/routing/awareness/zone/weights
{ 
      "weights":
      {
        "zone_1": "1", 
        "zone_2": "1", 
        "zone_3": "0"
      }
      "_version" : 1
}

{% include copy-curl.html %}

Response

{
     "acknowledged": true
}

Example: Getting weights for all zones

The following example request gets weights for all zones.

Request

GET /_cluster/routing/awareness/zone/weights

{% include copy-curl.html %}

Response

OpenSearch responds with the weight of each zone:

{
      "weights":
      {
      
        "zone_1": "1.0", 
        "zone_2": "1.0", 
        "zone_3": "0.0"
      },
      "_version":1
}

Example: Deleting weights

You can remove your weight ratio for each zone using the DELETE method.

Request

DELETE /_cluster/routing/awareness/zone/weights

{% include copy-curl.html %}

Response

{
   "_version":1
}

Next steps

• For more information about zone commissioning, see Cluster decommission.
• For more information about allocation awareness, see Cluster formation.