Creating a subnet

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Updated at October 17, 2024

Subnets are created in cloud networks. A new subnet is located in one of the availability zones. Resources can be connected to a subnet if they reside in the same availability zone as the subnet itself.

Management console

CLI

Terraform

API

In the management console, go to the folder where you need to create a subnet.
In the list of services, select Virtual Private Cloud.
In the left-hand panel, select Subnets.
At the top right, click Create.
In the Name field, specify the subnet name. The naming requirements are as follows:
- The name must be from 3 to 63 characters long.
- It may contain lowercase Latin letters, numbers, and hyphens.
- The first character must be a letter and the last character cannot be a hyphen.
(Optional) In the Description field, add a description.
In the Zone field, select an availability zone from the drop-down list.
In the Network field, specify a cloud network. Make sure to create it in advance.
In the CIDR field, enter the subnet IP address and mask.
For more information about subnet IP address ranges, see Cloud networks and subnets.
If you need to enter more CIDRs, click Add CIDR.
(Optional) Set DHCP settings. To do this:
1. In the Domain name field, specify a DNS domain to search for unqualified names.
2. In the Domain name servers field, click Add domain name server and enter the address of your DNS server. You can specify multiple DNS servers.
3. In the NTP servers field, click Add NTP server and enter the address of your NTP server. You can specify multiple NTP servers.
Click Create subnet.

If you do not have the Yandex Cloud command line interface yet, install and initialize it.

The folder specified in the CLI profile is used by default. You can specify a different folder using the --folder-name or --folder-id parameter.

To create a subnet:

See the description of the CLI command for creating a subnet:
```
yc vpc subnet create --help
```

Get a list of cloud networks in the required folder:

yc vpc network list --folder-id b1g6ci08ma55********

Result:

+----------------------+----------------+
|          ID          |      NAME      |
+----------------------+----------------+
| enpavfmgapum******** | test-network-1 |
| enplom7a98s1******** | default        |
+----------------------+----------------+

Select the NAME or ID of the cloud network you need. Create a subnet in the default folder:
```
yc vpc subnet create \
  --name test-subnet-1 \
  --description "My test subnet" \
  --network-id enplom7a98s1******** \
  --zone ru-central1-a \
  --range 192.168.0.0/24
```
Where:
- --network-id: Cloud network ID. You can also select a cloud network by specifying its name via the --network-name flag. Specify the name of the cloud network to create the subnet in and the CIDR.
- --zone: Availability zone where the subnet is created. If this flag is not set, the subnet is created in the default availability zone.
- --range: List of internal IPv4 addresses defined for this subnet, e.g., 10.0.0.0/22 or 192.168.0.0/16. Make sure the addresses are unique within the network. The minimum subnet size is /28, the maximum subnet size is /16. Only IPv4 is supported.
The subnet naming requirements are as follows:
- The name must be from 3 to 63 characters long.
- It may contain lowercase Latin letters, numbers, and hyphens.
- The first character must be a letter and the last character cannot be a hyphen.
```
yc vpc subnet create \
  --name test-subnet-1 \
  --description "My test subnet" \
  --network-name test-network-1 \
  --zone ru-central1-a \
  --range 192.168.0.0/24
```
The --name and --description flags are optional: you can create a subnet without any name or description and access it by ID.

Get a list of all subnets in the default folder:

yc vpc subnet list

Result:

+----------------------+-----------------------+------------------------+
|          ID          |         NAME          | ... |       RANGE      |
+----------------------+-----------------------+------------------------+
...
| e2l0psbfoloe******** | test-subnet-1         | ... | [192.168.0.0/24] |
...
+----------------------+-----------------------+-----+------------------+

Get the same list with more details in YAML format:

yc vpc subnet list --format yaml

Result:

...

- id: e2l0psbfoloe********
  folder_id: b1g6ci08ma55********
  created_at: "2018-10-24T12:25:58Z"
  name: test-subnet-1
  description: My test subnet
  network_id: enplom7a98s1********
  zone_id: ru-central1-a
  v4_cidr_blocks:
  - 192.168.0.0/24

...

Terraform allows you to quickly create a cloud infrastructure in Yandex Cloud and manage it using configuration files. Configuration files store the infrastructure description in the HashiCorp Configuration Language (HCL). Terraform and its providers are distributed under the Business Source License.

For more information about the provider resources, see the documentation on the Terraform website or the mirror.

If you change the configuration files, Terraform automatically detects which part of your configuration is already deployed, and what should be added or removed.

If you don't have Terraform, install it and configure the Yandex Cloud provider.

In the configuration file, describe the subnet parameters:
- name: Subnet name. The naming requirements are as follows:
  - The name must be from 3 to 63 characters long.
  - It may contain lowercase Latin letters, numbers, and hyphens.
  - The first character must be a letter and the last character cannot be a hyphen.
- description: Description of the subnet.
- v4_cidr_blocks: List of IPv4 addresses to deal with outgoing and incoming traffic, e.g., 10.0.0.0/22 or 192.168.0.0/16. Make sure the addresses are unique within the network. The minimum subnet size is /28, the maximum subnet size is /16. Only IPv4 is supported.
- zone: Availability zone.
- network_id: ID of the network where the subnet is created.
Here is an example of the configuration file structure:
```
resource "yandex_vpc_subnet" "lab-subnet-a" {
  name           = "<subnet_name>"
  description    = "<subnet_description>"
  v4_cidr_blocks = ["<IPv4_address>"]
  zone           = "<availability_zone>"
  network_id     = "<network_ID>"
}
```
To add, update, or delete a subnet, use the yandex_vpc_subnet resource with the network specified in the network_id field (see an example).

For more information about the parameters of the yandex_vpc_subnet resource in Terraform, see the provider documentation.
Make sure the configuration files are correct.
1. In the command line, go to the directory where you created the configuration file.
2. Run a check using this command:
```
terraform plan
```
If the configuration is described correctly, the terminal will display a list of created resources and their parameters. If the configuration contains any errors, Terraform will point them out.
Deploy cloud resources.
1. If the configuration does not contain any errors, run this command:
```
terraform apply
```
2. Confirm creating the resources: type yes in the terminal and press Enter.
  
  All the resources you need will then be created in the specified folder. You can check the new resources and their configuration using the management console or these CLI commands:
```
yc vpc subnet list
```

To create a subnet, use the create REST API method for the Subnet resource or the SubnetService/Create gRPC API call, and provide the following in the request:

ID of the folder where the subnet will be placed, in the folderId parameter.
ID of the network where the subnet will be placed, in the networkId parameter.
ID of the availability zone where the subnet will be placed, in the zoneId parameter.
List of internal IPv4 addresses defined for this subnet, in the v4CidrBlocks[] array, e.g., 10.0.0.0/22 or 192.168.0.0/16. Make sure the addresses are unique within the network. The minimum subnet size is /28, the maximum subnet size is /16. Only IPv4 is supported.

To get the subnet ID, use the list REST API method for the Subnet resource or the SubnetService/List gRPC API call and provide the folder ID in the folderId request parameter.

To learn how to find out the folder ID, see Getting the folder ID.

Examples

CLI

Terraform

Create a subnet with a name and description in the selected folder:

yc vpc subnet create \
  --name test-subnet-1 \
  --description "My test subnet" \
  --folder-id b1g6ci08ma55******** \
  --network-id enplom7a98s1******** \
  --zone ru-central1-a \
  --range 192.168.0.0/24

Create a subnet with DHCP settings:

yc vpc subnet create \
  --name test-subnet-1 \
  --description "My test subnet" \
  --folder-id b1g6ci08ma55******** \
  --network-id enplom7a98s1******** \
  --zone ru-central1-a \
  --range 192.168.0.0/24 \
  --domain-name test.domain \
  --domain-name-server 192.168.0.100 \
  --ntp-server 192.168.0.101

Describe the properties of the yandex_vpc_subnet resource in a configuration file:

resource "yandex_vpc_network" "lab-net" {
  name        = "network-1"
  description = "My first network"
}

resource "yandex_vpc_subnet" "lab-subnet-a" {
  name           = "subnet-1"
  description    = "My first subnet"
  v4_cidr_blocks = ["10.2.0.0/16"]
  zone           = "ru-central1-a"
  network_id     = "${yandex_vpc_network.lab-net.id}"
}

For more information about resource parameters in Terraform, see the provider documentation.

Make sure the configuration files are correct.
1. In the command line, go to the directory where you created the configuration file.
2. Run a check using this command:
```
terraform plan
```
If the configuration is described correctly, the terminal will display a list of created resources and their parameters. If the configuration contains any errors, Terraform will point them out.
Deploy cloud resources.
1. If the configuration does not contain any errors, run this command:
```
terraform apply
```
2. Confirm creating the resources: type yes in the terminal and press Enter.
  
  All the resources you need will then be created in the specified folder. You can check the new resources and their configuration using the management console or these CLI commands:
```
yc vpc subnet list
```

Creating a subnet

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