Create read-only instance - API Reference| Alibaba Cloud Documentation Center

Before you call this operation, make sure that the following requirements are met:

The primary instance must not 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 or Enterprise Edition
- MySQL 5.7 on RDS High-availability or Enterprise Edition
- MySQL 5.6
- SQL Server 2017 on RDS Cluster Edition
- PostgreSQL 10, 11, or 12 with local SSDs
If the primary instance runs MySQL, the number of existing read-only instances does not reach the specified limit:
- If the memory capacity of the primary instance is greater than or equal to 64 GB, up to 10 read-only instances are allowed.
- If the memory capacity of the primary instance is less than 64 GB, up to 5 read-only instances are allowed.
If the primary instance runs SQL Server, the number of existing read-only instances does not reach 7.
If the primary instance runs PostgreSQL with local SSDs, the number of existing read-only instances does not reach 5. If the primary instance runs PostgreSQL with standard or enhanced SSDs, the number of existing read-only instances does not reach 32.

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.
DBInstanceClass	String	Yes	rds.mys2.small	The type of the read-only instance. For more information, see Primary instance types. We recommend that the specifications of the read-only instance be higher than or equal to those of the primary instance. If the specifications of the read-only instance are lower than those of the primary instance, the read-only instance may encounter high latency or heavy load issues.
DBInstanceId	String	Yes	rm-uf6wjk5xxxxxxx	The ID of the primary instance.
DBInstanceStorage	Integer	Yes	20	The storage capacity of the read-only instance. Valid values: 5 to 3000. The value of this parameter must be a multiple of 5. Unit: GB. Note The supported storage capacity range varies based on the used RDS edition. For more information, go to the ApsaraDB RDS console.
EngineVersion	String	Yes	5.6	The version of the database engine that the read-only instance runs. The read-only instance must use the same database engine version as the primary instance. If the read-only instance runs MySQL, set the value to one of the following values: 5.6 5.7 8.0 If the read-only instance runs SQL Server, set the value to 2017_ent.
PayType	String	Yes	Postpaid	The billing method of the read-only instance. Valid value: Postpaid: pay-as-you-go Prepaid: subscription
RegionId	String	Yes	cn-hangzhou	The region ID of the read-only instance. The read-only instance must reside in the same region as the primary instance. You can call the DescribeRegions operation to query the most recent region list.
ZoneId	String	Yes	cn-hangzhou-b	The zone ID of the read-only instance. You can call the DescribeRegions operation to query the most recent zone list.
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.
DBInstanceDescription	String	No	Read-only instance for test	The description of the read-only instance. The description must be 2 to 256 characters in length. It can contain letters, digits, underscores (_), and hyphens (-). It 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.
VPCId	String	No	vpc-uf6f7l4fg90xxxxxxxxxx	The ID of the VPC to which the read-only instance belongs.
VSwitchId	String	No	vsw-uf6adz52c2pxxxxxxxxxx	The ID of the vSwitch associated with the specified VPC.
PrivateIpAddress	String	No	172.16.201.69	The private IP address of the read-only instance. The private IP address must fall within the Classless Inter-Domain Routing (CIDR) block that is supported by the specified vSwitch. The system automatically assigns a private IP address based on 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: the RDS Basic Edition. HighAvailability: the RDS High-availability Edition. AlwaysOn: the RDS Cluster Edition. Finance: the RDS Enterprise Edition. Note If the primary instance runs PostgreSQL with standard or enhanced SSDs, you must set this parameter to Basic.
DBInstanceStorageType	String	No	local_ssd	The type of storage media that is used by the read-only instance. Valid values: local_ssd or ephemeral_ssd: local SSD. cloud_ssd: standard SSD. cloud_essd: enhanced SSD. Note MySQL only supports local SSDs, whereas SQL Server supports both standard and enhanced SSDs.
DedicatedHostGroupId	String	No	dhg-4nxxxxxxx	The ID of the dedicated cluster to which the primary instance belongs if you create the read-only instance in a dedicated cluster.
TargetDedicatedHostIdForMaster	String	No	i-bpxxxxxxx1	The ID of the host to which the primary instance belongs if you create the read-only instance in a dedicated cluster.
GdnInstanceName	String	No	None	A hidden parameter.
TddlBizType	String	No	None	A hidden parameter.
TddlRegionConfig	String	No	None	A hidden parameter.
InstructionSetArch	String	No	None	A hidden parameter.

Response parameters


Parameter	Type	Example	Description
DBInstanceId	String	rr-uf6wjk5xxxxxxx	The ID of the read-only instance.
OrderId	String	10078937xxxxx	The ID of the order.
ConnectionString	String	rr-xxxxx.mysql.rds.aliyuncs.com	The internal endpoint of the read-only instance.
Port	String	3306	The internal port of the read-only instance.
RequestId	String	1E43AAE0-BEE8-43DA-860D-EAF2AA0724DC	The ID of the request.

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
&<Common request parameters>

Sample success responses

XML format

<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

{
    "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 EngineVersion parameter is invalid.
400	InvalidSecurityIPList.Malformed	The specified parameter "SecurityIPList" is not valid.	The error message returned because the specified SecurityIPList parameter 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.
400	InvalidParameter	The specified parameter "dbInstanceId" is not valid.	The error message returned because the specified DBInstanceId parameter is invalid.
403	OperationDenied.PrimaryDBInstanceStatus	The operation is not permitted due to status of primary instance.	The error message returned because the status of the primary instance does not support this operation. The primary instance supports this operation only when it is in the Running state.
400	OperationDenied	VPC IP is in use, please check.	The error message returned because the specified private IP address is in use. Change the private IP address and try again.
404	IncorrectDBInstanceConnType	Current DB instance conn type does not support this operation.	The error message returned because the connection type of the primary instance does not support this operation.
400	InvalidZoneId.NotSupported	The Specified vpc Zone not supported.	The error message returned because the specified zone does not support instances that reside in VPCs. Change the zone and try again.

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