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

Adding Instances and Expanding Instance Storage Capacity

Function

If a cluster struggles to maintain performance in the face of rapid data growth or sustained high memory usage, you can add more nodes to it or increase the storage capacity of its existing nodes.

Constraints

The node storage capacity of a cluster can only be increased—not decreased. Select an appropriate node storage capacity based on the data volume and projected data growth.
For a pay-per-use cluster, you cannot increase the number of nodes and node storage capacity at the same time. .
The storage capacity of the master and client nodes in a cluster cannot be expanded.
The storage capacity of data nodes that use local disks cannot be expanded.
For a Logstash cluster, you can only add more nodes, but cannot increase the storage capacity of its nodes.

Calling Method

For details, see Calling APIs.

URI

POST /v1.0/{project_id}/clusters/{cluster_id}/role_extend

**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 out. 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
grow	Yes	Array of RoleExtendGrowReq objects	Definition Description of the cluster scale-out request, including fields such as type, nodesize, and disksize, which are used to specify the type of nodes to be added, number of instances, and storage capacity. Constraints N/A

**Table 3** RoleExtendGrowReq
Parameter	Mandatory	Type	Description
type	Yes	String	Definition Type of the node to be added. Constraints You can only add instances, rather than increase storage capacity, on nodes of the ess-master, ess-client, and lgs types. The value must be a valid node type and can contain only lowercase letters and hyphens (-). Range ess: data node ess-master: master node ess-client: client node ess-cold: cold data node lgs: Logstash nodes in Logstash clusters You can select multiple node types, but cannot select the same node for different roles. NOTE: lgs cannot be combined with other options. Default Value N/A
nodesize	Yes	Integer	Definition Number of instances to be added. Constraints After scaling, the number of nodes of each type must meet the following requirements: Data nodes: If the cluster does not have master nodes, the value ranges from 1 to 32. Otherwise, the value ranges from 1 to 200. Master nodes: 3, 5, 7, or 9 (must be an odd number from 3 to 9) Client nodes: 1 to 64 Cold data nodes: 1 to 32 Logstash nodes: 1 to 100 Range N/A Default Value N/A
disksize	Yes	Integer	Definition Storage capacity to be added, in GB. Constraints The sum of the original instance storage capacity plus the expanded instance storage capacity cannot exceed the default upper limit of storage capacity set during cluster creation. If there is no need to add more instances, set this parameter to 0. The scale-out step of ess and ess-cold nodes is 20. The storage capacity of ess-master and ess-client nodes cannot be expanded. Logstash does not support storage capacity expansion. Range N/A Default Value N/A

Response Parameters

Status code: 200

**Table 4** Response body parameters
Parameter	Type	Description
id	String	Definition: Cluster ID. Value range: N/A

Example Requests

Change the number of instances and storage capacity of the current cluster.

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

{
  "grow" : [ {
    "type" : "ess",
    "nodesize" : 0,
    "disksize" : 40
  } ],
  "is_auto_pay" : 1
}

Example Responses

Status code: 200

Request succeeded.

{
  "id" : "4f3deec3-efa8-4598-bf91-560aad1377a3"
}

Status Codes

Status Code	Description
200	Request succeeded.
400	Invalid request. Modify the request before retry.
404	The requested resource could not be found. Modify the request before retry.

Status Code

Description

200

Request succeeded.

400

Invalid request.

Modify the request before retry.

404

The requested resource could not be found.