You can call the CreateReadOnlyDBInstance operation to create a read-only instance for a primary ApsaraDB RDS instance.

Before you call this operation, take note of the following limits:
  • The primary instance cannot belong to a dedicated cluster and must run one of the following database engine versions and RDS editions:
    • MySQL 8.0 on RDS High-availability Edition or RDS Enterprise Edition
    • MySQL 5.7 on RDS High-availability Edition or RDS Enterprise Edition
    • MySQL 5.6
    • SQL Server 2017 EE
    • PostgreSQL 10, 11, or 12 on RDS High-availability Edition (If the primary instance runs PostgreSQL 10, it must use local SSDs.)
  • If the primary instance runs MySQL, you can create up to 10 read-only instances.
  • If the primary instance runs SQL Server, you can create up to seven read-only instances.
  • If the primary instance runs PostgreSQL with local SSDs, you can create up to five read-only instances. If the primary instance runs PostgreSQL with standard SSDs or enhanced SSDs (ESSDs), you can create up to 32 read-only instances.

Debugging

OpenAPI Explorer automatically calculates the signature value. For your convenience, we recommend that you call this operation in OpenAPI Explorer. OpenAPI Explorer dynamically generates the sample code of the operation for different SDKs.

Request parameters

Parameter Type Required Example Description
Action String Yes CreateReadOnlyDBInstance

The operation that you want to perform. Set the value to CreateReadOnlyDBInstance.

ClientToken String No ETnLKlblzczshOTUbOCzxxxxxxxxxx

The client token that is used to ensure the idempotence of the request. You can use the client to generate the value, but you must ensure that it is unique among different requests. The token can only contain ASCII characters and cannot exceed 64 characters in length.

RegionId String Yes cn-hangzhou

The ID of the region in which the read-only instance resides. The read-only instance and the primary instance must reside in the same region. You can call the DescribeRegions operation to query the most recent region list.

ZoneId String Yes cn-hangzhou-b

The ID of the zone to which the read-only instance belongs. You can call the DescribeRegions operation to query the most recent zone list.

DBInstanceId String Yes rm-uf6wjk5xxxxxxx

The ID of the primary instance.

DBInstanceClass String Yes rds.mys2.small

The instance type of the read-only instance. For more information, see Read-only ApsaraDB RDS instance types. We recommend that you specify an instance type whose specifications are higher than or equal to the specifications of the instance type of the primary instance. If the specifications of the read-only instance are lower than the specifications of the primary instance, the read-only instance may encounter issues such as high latency and heavy load.

DBInstanceStorage Integer Yes 20

The storage capacity of the read-only instance. Valid values: 5 to 3000. Unit: GB. The storage capacity increases in increments of 5 GB.

Note The storage capacity range that is supported varies based on the RDS edition that is run by the read-only instance. For more information, visit the ApsaraDB RDS buy page.
EngineVersion String Yes 5.6

The major engine version of the read-only instance. The read-only instance and the primary instance must run the same major engine version.

  • If the read-only instance runs MySQL, set this parameter to 5.6, 5.7, or 8.0.
  • If the read-only instance runs SQL Server, set this parameter to 2017_ent or 2019_ent.
PayType String Yes Postpaid

The billing method of the read-only instance. Valid values:

  • Postpaid: pay-as-you-go
  • Prepaid: subscription
DBInstanceDescription String No Test read-only instance

The description of the read-only instance. The description must be 2 to 256 characters in length and can contain letters, digits, underscores (_), and hyphens (-). The description must start with a letter.

Note The description cannot start with http:// or https://.
InstanceNetworkType String No Classic

The network type of the read-only instance. Valid values:

  • VPC
  • Classic

Default value: VPC. If you set this parameter to VPC, you must also specify the VPCId and VSwitchId parameters.

Note The network type of the read-only instance can be different from the network type of the primary instance.
VPCId String No vpc-uf6f7l4fg90xxxxxxxxxx

The ID of the virtual private cloud (VPC) to which the read-only instance belongs. If you leave the InstanceNetworkType parameter empty or set it to VPC, you must specify the VPCId parameter.

Note
  • If the primary instance uses local SSDs, the read-only instance and the primary instance can belong to the same VPC or different VPCs.
  • If the primary instance uses standard SSDs or ESSDs, the read-only instance and the primary instance must belong to the same VPC.
VSwitchId String No vsw-uf6adz52c2pxxxxxxxxxx

The ID of the vSwitch to which the read-only instance belongs. If you leave the InstanceNetworkType parameter empty or set it to VPC, you must specify the VPCId parameter.

PrivateIpAddress String No 172.16.201.69

The private IP address of the read-only instance. The private IP address must be within the CIDR block that is supported by the specified vSwitch. The system automatically assigns a private IP address to the read-only instance based on the values of the VPCId and VSwitchId parameters.

ResourceGroupId String No rg-acfmyxxxxxxxxxx

The ID of the resource group to which the read-only instance belongs.

Category String No HighAvailability

The RDS edition of the read-only instance. Valid values:

  • Basic: Basic Edition.
  • HighAvailability: High-availability Edition. This is the default value.
  • AlwaysOn: Cluster Edition.
  • Finance: Enterprise Edition. This edition is available only on the China site (aliyun.com).
Note If the read-only instance runs PostgreSQL with standard SSDs or ESSDs, you must set this parameter to Basic.
DBInstanceStorageType String No local_ssd

The type of storage media that is used by the instance. Valid values:

  • local_ssd: local SSDs
  • cloud_ssd: standard SSDs
  • cloud_essd: ESSDs of performance level 1 (PL1)
  • cloud_essd2: ESSDs of PL2
  • cloud_essd3: ESSDs of PL3
Note
  • If the primary instance runs MySQL with local SSDs, you must set this parameter to local_ssd. If the primary instance runs MySQL with standard SSDs or ESSDs, you must set this parameter to cloud_ssd, cloud_essd, cloud_essd2, or cloud_essd3.
  • If the primary instance runs SQL Server, you must set this parameter to cloud_ssd, cloud_essd, cloud_essd2, or cloud_essd3.
DedicatedHostGroupId String No dhg-4nxxxxxxx

The ID of the dedicated cluster to which the read-only instance belongs. This parameter is valid when you create the read-only instance in a dedicated cluster.

TargetDedicatedHostIdForMaster String No i-bpxxxxxxx1

The ID of the host to which the read-only instance belongs. This parameter is valid when you create the read-only instance in a dedicated cluster.

GdnInstanceName String No None

A reserved parameter.

TddlBizType String No None

A reserved parameter.

TddlRegionConfig String No None

A reserved parameter.

InstructionSetArch String No None

A reserved parameter.

UsedTime String No 1

The subscription period of the read-only instance. Valid values:

  • If you set the Period parameter to Year, the value of the UsedTime parameter ranges from 1 to 5.
  • If you set the Period parameter to Month, the value of the UsedTime parameter ranges from 1 to 9.
Note If you set the PayType parameter to Prepaid, you must specify the UsedTime parameter.
Period String No Month

The renewal cycle of the read-only instance. Valid values:

  • Year
  • Month
AutoRenew String No true

Specifies whether to enable auto-renewal for the read-only instance. If you specify the subscription billing method for the read-only instance, you must specify this parameter. Valid values:

  • true: enables auto-renewal.
  • false: disables auto-renewal.
Note
  • If you set the Period parameter to Month, the auto-renewal cycle is one month.
  • If you set the Period parameter to Year, the auto-renewal cycle is one year.

Response parameters

Parameter Type Example Description
DBInstanceId String rr-uf6wjk5xxxxxxx

The ID of the read-only instance.

RequestId String 1E43AAE0-BEE8-43DA-860D-EAF2AA0724DC

The ID of the request.

Port String 3306

The internal port number that is used to connect to the read-only instance.

ConnectionString String rr-xxxxx.mysql.rds.aliyuncs.com

The internal endpoint that is used to connect to the read-only instance.

OrderId String 10078937xxxxx

The ID of the order.

Examples

Sample requests

http(s)://rds.aliyuncs.com/?Action=CreateReadOnlyDBInstance
&RegionId=cn-hangzhou
&ZoneId=cn-hangzhou-b
&DBInstanceId=rm-uf6wjk5xxxxxxx
&DBInstanceClass=rds.mys2.small
&DBInstanceStorage=20
&EngineVersion=5.6
&PayType=Postpaid
&VPCId=vpc-uf6f7l4fg90xxxxxxxxxx
&VSwitchId=vsw-uf6adz52c2pxxxxxxxxxx
&<Common request parameters>

Sample success responses

XML format

HTTP/1.1 200 OK
Content-Type:application/xml

<CreateReadOnlyDBInstanceResponse>
    <OrderId>10078937xxxxx</OrderId>
    <ConnectionString>rm-uf6wjk5xxxxxxx.mysql.rds.aliyuncs.com</ConnectionString>
    <DBInstanceId>rm-uf6wjk5xxxxxxx</DBInstanceId>
    <Port>3306</Port>
    <RequestId>1E43AAE0-BEE8-43DA-860D-EAF2AA0724DC</RequestId>
</CreateReadOnlyDBInstanceResponse>

JSON format

HTTP/1.1 200 OK
Content-Type:application/json

{
  "CreateReadOnlyDBInstanceResponse" : {
    "OrderId" : "10078937xxxxx",
    "ConnectionString" : "rm-uf6wjk5xxxxxxx.mysql.rds.aliyuncs.com",
    "DBInstanceId" : "rm-uf6wjk5xxxxxxx",
    "Port" : 3306,
    "RequestId" : "1E43AAE0-BEE8-43DA-860D-EAF2AA0724DC"
  }
}

Error codes

HTTP status code Error code Error message Description
400 InvalidEngineVersion.Malformed The specified parameter "EngineVersion" is not valid. The error message returned because the specified database engine version is invalid.
400 InvalidSecurityIPList.Malformed The specified parameter "SecurityIPList" is not valid. The error message returned because the IP address whitelist of the read-only instance is invalid.
400 InvalidSecurityIPList.Duplicate The Security IP address is not in the available range or occupied. The error message returned because the specified IP address is in use or is not within the valid range. Specify a valid IP address and try again.
400 InvalidParameter The specified parameter "dbInstanceId" is not valid. The error message returned because the specified instance ID is invalid. Specify a valid instance ID and try again.
400 OperationDenied VPC IP is in use, please check. The error message returned because the specified VPC IP address is in use.
400 InvalidZoneId.NotSupported The Specified vpc Zone not supported. The error message returned because the specified zone does not allow you to create an instance in a VPC. Specify a different zone and try again.
400 CDDC.AvailableHostsNotEnoughInZone Not enough available hosts are in the target zone. The error message returned because no hosts are available in the specified zone. Create a host in the zone and try again.
403 OperationDenied.PrimaryDBInstanceStatus The operation is not permitted due to status of primary instance. The error message returned because the instance belongs to a dedicated cluster and is not in the Running state.
404 IncorrectDBInstanceConnType Current DB instance conn type does not support this operation. The error message returned because this operation is not supported by the network connection type of the instance.
500 CannotDecreaseEssdPerfLevel cannot decrease cloud essd performance level. The error message returned because the storage type change fails verification. The storage type of an instance that runs SQL Server with cloud disks can be converted only to a different type of cloud disk. An instance that runs SQL Server with standard SSDs can be upgraded to use standard SSDs or ESSDs with the new specifications.
500 InvalidEssdStorageSize invalid cloud essd storage size. The error message returned because the specified instance type is invalid. Select a valid instance type and try again.

For a list of error codes, visit the API Error Center.