Help Center/ Distributed Database Middleware/ API Reference/ APIs (Recommended)/ DDM Instances/ Scaling Out a DDM Instance (a V3 API)
Updated on 2026-05-30 GMT+08:00
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Scaling Out a DDM Instance (a V3 API)

Function

This API is used to scale out a specified DDM instance. Pay-per-use and yearly/monthly instances are all supported.

Constraints

Make sure that the associated RDS instances are available and not undergoing other operations.

URI

  • URL format

    POST /v3/{project_id}/instances/{instance_id}/nodes

  • Parameter description
    Table 1 URI parameters

    Parameter

    Mandatory

    Type

    Description

    project_id

    Yes

    String

    Project ID of a tenant in a region

    To obtain this value, see Obtaining a Project ID.

    instance_id

    Yes

    String

    DDM instance ID

Request Parameters

Table 2 Request header parameters

Parameter

Mandatory

Type

Description

X-Auth-Token

Yes

String

User token.

You can obtain the token by calling the IAM API used to obtain a user token.
Table 3 Request body parameters

Parameter

Mandatory

Type

Description

group_id

No

String

Group ID, which specifies the group that is scaled out. This parameter must be specified if there are more than one node group.

subnet_id

No

String

Subnet ID. This parameter is mandatory when there are more than one subnet in the node group.

is_auto_pay

No

Boolean

Whether to automatically pay with your account. This parameter can be specified when nodes are added for a yearly/monthly instance.

  • true: indicates that the order is automatically paid from the account.
  • false: indicates that the order is manually paid from the account. The default value is false.

nodes

Yes

Array of Table EnlargeNodeInfo objects

Node information list.

The list can include at least one node.

The list can include a maximum of 32 nodes.
Table 4 EnlargeNodeInfo

Parameter

Mandatory

Type

Description

available_zone

Yes

String

AZ where the node is located. The value cannot be empty. For details, see Regions and Endpoints.

Example Request

Scaling out a pay-per-use DDM instance. The number of nodes to be added is 1.

POST https://{endpoint}/v3/{project_id}/instances/{instance_id}/nodes
{
     "nodes": [
        {
            "available_zone": "az1"
        }
    ]
}

Scaling out a pay-per-use DDM instance that has more than one group. Each group has multiple subnets. The number of nodes to be added is 1.

POST https://{endpoint}/v3/{project_id}/instances/{instance_id}/nodes
{
    "group_id": "efd077a3a50e460c8ba62e1956363299gr09",
    "subnet_id": "ead1e945-ca89-45dd-bcce-4a30b2054c22",
     "nodes": [
        {
            "available_zone": "az1"
        }
    ]
}
Scaling out a yearly/monthly DDM instance. The number of nodes to be added is 1, and the order is paid from your account balance. 
POST https://{endpoint}/v3/{project_id}/instances/{instance_id}/nodes
{
    "is_auto_pay" : true,
     "nodes": [
        {
            "available_zone": "az1"
        }
    ]
}

Response

  • Normal response
    Table 5 Response body parameters

    Parameter

    Type

    Description

    job_id

    String

    ID of a node scale-out task.

    This parameter is returned only for node scale-out of a pay-per-use instance.

    order_id

    String

    Order ID. This parameter is returned only for node scale-out of a yearly/monthly instance.
  • Normal response example

    Buying a pay-per-use instance:

    {
  "job_id": "eff1d289-4d03-4942-8b9f-463ea07c000c"
}

    Buying a yearly/monthly instance:

    {
  "order_id" : "CS1810251738L8VVD" 
}

Status Codes

Error Codes

For details, see Error Codes.

Parent topic: DDM Instances