Updated on 2026-09-02 GMT+08:00

Scaling In Nodes of a Specific Type

Function

This API is used to scale in instances of different types and reduce the storage capacity of a cluster.

Before scaling in, back up all key data to prevent data loss.

Calling Method

For details, see Calling APIs.

URI

POST /v1.0/extend/{project_id}/clusters/{cluster_id}/role/shrink

**Table 1** Path Parameters
Parameter	Mandatory	Type	Description
project_id	Yes	String	Definition Project ID. For details about how to obtain the project ID and name, see Obtaining the Project ID and Name. Constraints N/A Range Project ID of an account. The value contains 32 characters, consisting of lowercase letters and digits. Default Value N/A
cluster_id	Yes	String	Definition ID of the cluster to be scaled in. For details about how to obtain the cluster ID, see Obtaining the Cluster ID. Constraints N/A Range The value is a UUID containing 36 characters. Default Value N/A

Request Parameters

**Table 2** Request body parameters
Parameter	Mandatory	Type	Description
shrink	Yes	Array of ShrinkNodeReq objects	Definition Type and quantity of nodes you want to scale in. Constraints N/A
agency_name	No	String	Definition Agency name. You can create an agency to allow CSS to call other cloud services. Constraints VPC permissions required by the agency: "vpc:subnets:get","vpc:ports:". This parameter is mandatory when the new IAM plane is connected. This parameter is optional when the old IAM plane is connected. The agency name can contain at most 64 characters. Only letters, digits, underscores (_), and hyphens (-) are allowed. Range* N/A Default Value N/A
operation_type	No	String	Definition Scale-in type. Constraints N/A Range vm: Reduce nodes. Default Value vm
cluster_load_check	No	Boolean	Definition: Whether to check the cluster load. Constraints: N/A Value range: true: enable cluster load check. true: skip cluster load check. Default value: true

**Table 3** ShrinkNodeReq
Parameter	Mandatory	Type	Description
reducedNodeNum	Yes	Integer	Definition Number of nodes to be scaled in. Constraints After the scale-in, there must be at least one instance for each node type in each AZ. For cross-AZ clusters, the number of same-type nodes in different AZs must not differ by more than 1. For clusters with two AZs, at least two data nodes (ess) or cold data nodes (ess-cold) must be deployed in each AZ. For a cluster with no Master nodes, the number of removed data nodes (including cold data nodes and other types of nodes) in a scale-in must be fewer than half of the number of the original data nodes, and the number of remaining data nodes after a scale-in must be greater than the maximum number of index replicas. For a cluster with master nodes, the number of removed master nodes in a scale-in must be fewer than half of the number of the original master nodes. After scale-in, there has to be an odd number of master nodes, and there has to be at least three of them. Range N/A Default Value N/A
type	Yes	String	Definition Node type. Constraints N/A Range ess: data node ess-cold: cold data node ess-client: client node ess-master: master node lgs: Logstash node Default Value N/A

Response Parameters

Status code: 200

Request succeeded.

None

Example Requests

Scale in a cluster by specifying the node type and the number of nodes to be removed.

POST https://{Endpoint}/v1.0/extend/{project_id}/clusters/4f3deec3-efa8-4598-bf91-560aad1377a3/role/shrink

{
  "shrink" : [ {
    "type" : "ess",
    "reducedNodeNum" : 1
  } ]
}

Example Responses

None

Status Codes

Status Code	Description
200	Request succeeded.
400	Invalid request. Modify the request before retry.
409	The request could not be completed due to a conflict with the current state of the resource. The resource that the client attempts to create already exists, or the update request fails to be processed because of a conflict.
412	The server did not meet one of the preconditions contained in the request.

Error Codes

See Error Codes.

Parent topic: Modify Configuration