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    PolarDB:CreateDBNodes

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    PolarDB:CreateDBNodes

    Last Updated:Dec 11, 2025

    Adds one or more read-only nodes to a PolarDB cluster.

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    RAM authorization

    The table below describes the authorization required to call this API. You can define it in a Resource Access Management (RAM) policy. The table's columns are detailed below:

    • Action: The actions can be used in the Action element of RAM permission policy statements to grant permissions to perform the operation.

    • API: The API that you can call to perform the action.

    • Access level: The predefined level of access granted for each API. Valid values: create, list, get, update, and delete.

    • Resource type: The type of the resource that supports authorization to perform the action. It indicates if the action supports resource-level permission. The specified resource must be compatible with the action. Otherwise, the policy will be ineffective.

      • For APIs with resource-level permissions, required resource types are marked with an asterisk (*). Specify the corresponding Alibaba Cloud Resource Name (ARN) in the Resource element of the policy.

      • For APIs without resource-level permissions, it is shown as All Resources. Use an asterisk (*) in the Resource element of the policy.

    • Condition key: The condition keys defined by the service. The key allows for granular control, applying to either actions alone or actions associated with specific resources. In addition to service-specific condition keys, Alibaba Cloud provides a set of common condition keys applicable across all RAM-supported services.

    • Dependent action: The dependent actions required to run the action. To complete the action, the RAM user or the RAM role must have the permissions to perform all dependent actions.

    Action

    Access level

    Resource type

    Condition key

    Dependent action

    polardb:CreateDBNodes

    create

    *dbcluster

    acs:polardb:{#regionId}:{#accountId}:dbcluster/{#dbclusterId}

    		 None None

    Request parameters

    Parameter

    Type

    Required

    Description

    Example
    ResourceGroupId

    string

    No

    The ID of the resource group.

    rg-************
    DBClusterId

    string

    Yes

    The cluster ID.

    pc-*************
    ClientToken

    string

    No

    A client token used to ensure the idempotence of the request. The client generates this token, but you must make sure that the token is unique among different requests. The token is case-sensitive and can contain up to 64 ASCII characters.

    6000170000591aed949d0f54a343f1a4233c1e7d1c5c******
    EndpointBindList

    string

    No

    The ID of the cluster endpoint to which the new node is to be added. Separate multiple endpoint IDs with commas (,).

    Note

    • You can call the DescribeDBClusterEndpoints operation to query the details of cluster endpoints, including the endpoint IDs.

    • You can specify the IDs of default and custom cluster endpoints.

    • If you leave this parameter empty, the new node is added to all cluster endpoints for which the Auto Add New Nodes feature is enabled. This means the AutoAddNewNodes parameter is set to Enable.

    pe-****************,pe-****************
    PlannedStartTime

    string

    No

    The earliest time to start the scheduled task to add the node. The time is in the YYYY-MM-DDThh:mm:ssZ format. The time is displayed in UTC.

    Note

    • The start time can be any point in time within the next 24 hours. For example, if the current time is 2021-01-14T09:00:00Z, you can set the start time to a value from 2021-01-14T09:00:00Z to 2021-01-15T09:00:00Z.

    • If you leave this parameter empty, the task to add the node is executed immediately.

    2021-01-14T09:00:00Z
    PlannedEndTime

    string

    No

    The latest time to start the scheduled task. The time is in the YYYY-MM-DDThh:mm:ssZ format. The time is displayed in UTC.

    Note

    • The latest start time must be at least 30 minutes later than the earliest start time.

    • If you specify PlannedStartTime but not this parameter, the latest start time of the task is PlannedStartTime + 30 minutes. For example, if you set PlannedStartTime to 2021-01-14T09:00:00Z and leave this parameter empty, the task starts no later than 2021-01-14T09:30:00Z.

    2021-01-14T09:30:00Z
    DBNode

    array<object>

    Yes

    The information about the new nodes.

    object

    No

    TargetClass

    string

    No

    The specifications of the new node. These must be the same as the specifications of the existing nodes. For more information, see the following documents:

    Note

    • You must specify at least one of `DBNode.N.ZoneId` and `DBNode.N.TargetClass`. N is an integer that starts from 1. The maximum value of N is 16 minus the number of existing nodes.

    • Currently, you can add multiple read-only nodes to only a PolarDB for MySQL cluster at a time. You can add a maximum of 15 read-only nodes.

    • This parameter is required for PolarDB for PostgreSQL (Oracle Compatible) clusters and PolarDB for PostgreSQL clusters. This parameter is optional for PolarDB for MySQL clusters.

    polar.mysql.x4.medium
    ZoneId

    string

    No

    The zone ID of the new node. The new node must be in the same zone as the existing nodes. You can call the DescribeRegions operation to query the zone ID.

    Note

    • You must specify at least one of `DBNode.N.ZoneId` and `DBNode.N.TargetClass`. N is an integer that starts from 1. The maximum value of N is 16 minus the number of existing nodes.

    • Currently, you can add multiple read-only nodes to only a PolarDB for MySQL cluster at a time. You can add a maximum of 15 read-only nodes.

    • This parameter is required for PolarDB for PostgreSQL (Oracle Compatible) clusters and PolarDB for PostgreSQL clusters. This parameter is optional for PolarDB for MySQL clusters.

    cn-qingdao-c
    DBNodeType

    string

    No

    The node type. Valid values:

    • RO

    • STANDBY

    • DLNode

    Valid values:

    • DLNode :

      AI node

    • STANDBY :

      Standby node

    • RO :

      Read-only node

    RO
    ImciSwitch

    string

    No

    Specifies whether to enable the In-Memory Column Index (IMCI) feature. Valid values:

    • ON: Enables IMCI.

    • OFF: Disables IMCI. This is the default value.

    Note

    This parameter is not supported by PolarDB for PostgreSQL (Oracle Compatible) or PolarDB for PostgreSQL.

    ON
    CloudProvider

    string

    No

    ENS
    AutoUseCoupon

    boolean

    No

    PromotionCode

    string

    No

    727xxxxxx934

    Response elements

    Element

    Type

    Description

    Example

    object

    DBNodeIds

    object

    DBNodeId

    array

    The list of created node IDs.

    string

    The ID of a created node.

    pi-***************
    RequestId

    string

    The request ID.

    E053E730-5755-4AA9-AA9D-A47867******
    DBClusterId

    string

    The ID of the database cluster.

    pc-***************
    OrderId

    string

    The order ID.

    2148126708*****

    Examples

    Success response

    JSON format

    {
  "DBNodeIds": {
    "DBNodeId": [
      "pi-***************"
    ]
  },
  "RequestId": "E053E730-5755-4AA9-AA9D-A47867******",
  "DBClusterId": "pc-***************",
  "OrderId": "2148126708*****"
}

    Error codes

    HTTP status code

    Error code

    Error message

    Description
    400 ORDER.ARREARAGE 您有欠费账单，不符合购买条件，请先结清账单后再购买 You must settle the overdue payments for your account before you can make a purchase.
    400 InvalidDBNodeNum.Malformed The number of parameter DBNode.N is not valid. The specified number of database nodes is invalid.
    400 InvalidDBNode.Malformed The specified parameter DBNode.N is not valid. The specified DBNode.N parameter is invalid.
    400 OperationDenied.CreateDBNodesWithStrictConsistencyOn 3AZ cluster does not allow create db nodes. Nodes cannot be added for multi-zone clusters.
    400 InvalidZoneId.Malformed The specified parameter ZoneId is not valid. The specified ZoneId parameter is invalid.
    403 OperationDenied.ClusterCategory The operation is not permitted due to cluster category. This series is not supported by the cluster.
    403 OperationDenied.DbVersion The operation is not permitted due to DbVersion. This operation is not supported by the database version.
    404 InvalidDBClusterId.NotFound The DBClusterId provided does not exist in our records. The specified DBClusterId parameter does not exist in the current record.
    404 InvalidDBClusterId.Malformed The specified parameter DBClusterId is not valid. The specified DBClusterId parameter is invalid.

    See Error Codes for a complete list.

    Release notes

    See Release Notes for a complete list.