You must create a VPC before creating a subnet.
Once a subnet is created, its IP address range cannot be changed. The subnet IP address range must lie within the VPC IP address range. They can be the same, in which case the VPC only has one subnet. It is recommended to keep the subnet IP address range within the VPC IP address range to reserve IP address range for other subnets.
The subnet mask of the smallest IP address range that can be created is 28 (16 IP addresses), and that of the largest IP address range is 16 (65,536 IP addresses).
IP address ranges of different subnets cannot overlap with each other within the same VPC.
A subnet is automatically associated to the default route table once created.

A maximum of 100 requests can be initiated per second for this API.

Note: This API supports Finance regions. Since Finance regions and non-Finance regions are isolated and not interconnected. If the common parameter Region is a Finance region (such as ap-shanghai-fsi), you need to specify a domain name containing the Finance region that should be identical to the value of Region field, for example: vpc.ap-shanghai-fsi.tencentcloudapi.com.

2. Input Parameters

The following request parameter list only provides API request parameters and some common parameters. For the complete common parameter list, see Common Request Parameters.

Parameter Name	Required	Type	Description
Action	Yes	String	Common parameter. The value used for this API: CreateSubnet
Version	Yes	String	Common parameter. The value used for this API: 2017-03-12
Region	Yes	String	Common parameter. For more information, please see the list of regions supported by the product.
VpcId	Yes	String	ID of the VPC instance you are working with. You can obtain the parameter value from the VpcId field value in the returned result of API DescribeVpcs.
SubnetName	Yes	String	Subnet name, which is limited to 60 bytes.
CidrBlock	Yes	String	Subnet IP address range. It must lie within the VPC IP address range. Subnet IP address ranges cannot overlap with each other within the same VPC.
Zone	Yes	String	ID of the availability zone in which the subnet resides. You may set up disaster recovery across availability zones by choosing different availability zones for different subnets.

3. Output Parameters

Parameter Name	Type	Description
Subnet	Subnet	Subnet object.
RequestId	String	The unique request ID, which is returned for each request. RequestId is required for locating a problem.

4. Error Codes

The following only lists the error codes related to the API business logic. For other error codes, see Common Error Codes.

Error Code	Description
InvalidParameterValue.SubnetConflict	Subnet CIDR conflict.
InvalidParameterValue.SubnetRange	Invalid subnet CIDR.
LimitExceeded	Quota exceeded.

5. Example

Example 1 Create a subnet

Input example

https://vpc.tencentcloudapi.com/?Action=CreateSubnet
&Version=2017-03-12
&VpcId=vpc-m3ul053f
&VpcName=TestSubnet
&CidrBlock=10.8.0.0/16
&Zone=ap-guangzhou-1
&<Common request parameters>

Output example

{
  "Response": {
    "RequestID": "354f4ac3-8546-4516-8c8a-69e3ab73aa8a",
    "Subnet": {
      "AvailableIpAddressCount": 253,
      "CidrBlock": "10.8.255.0/24",
      "IsDefault": false,
      "SubnetId": "subnet-2qhl25io",
      "SubnetName": "TestSubnet",
      "VpcId": "vpc-m3ul053f",
      "Zone": "ap-guangzhou-1"
    }
  }
}

6. Other Resources

Cloud API 3.0 comes with the following development tools to make it easier to call the API.

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Help & Documentation

CreateSubnet

Contents:

1. API Description