Connect a Cloud Platform private network to a DNS resolver via Terraform

Last update: October 05 2026Open in Markdown

If a Cloud Platform private network is connected to a DNS resolver, cloud servers in this network can resolve domain names of all zones within their pool and project.

We recommend creating resources sequentially. If you create all resources at the same time, Terraform will take into account the dependencies between resources that you specified in the configuration file. If dependencies are not specified, resources will be created in parallel, which may lead to errors. For example, a resource required to create another resource may not be created yet.

1. Optional: configure providers.
2. Create a private network and subnet.
3. Connect the network to the DNS resolver.
4. Specify the DNS resolver IP addresses in the subnet settings.

Configuration files

Example file for configuring providers

terraform {
  required_providers {
    selectel  = {
      source  = "selectel/selectel"
      version = "~> 6.0"
    }
    openstack = {
      source  = "terraform-provider-openstack/openstack"
      version = "2.1.0"
    }
  }
}

provider "selectel" {
  domain_name = "123456"
  username    = "user"
  password    = "password"
  auth_region = "ru-9"
  auth_url    = "https://cloud.api.selcloud.ru/identity/v3/"
}

resource "selectel_vpc_project_v2" "project_1" {
  name = "project"
}

resource "selectel_iam_serviceuser_v1" "serviceuser_1" {
  name         = "username"
  password     = "password"
  role {
    role_name  = "member"
    scope      = "project"
    project_id = selectel_vpc_project_v2.project_1.id 
  }
}

provider "openstack" {
  auth_url    = "https://cloud.api.selcloud.ru/identity/v3"
  domain_name = "123456"
  tenant_id   = selectel_vpc_project_v2.project_1.id
  user_name   = selectel_iam_serviceuser_v1.serviceuser_1.name
  password    = selectel_iam_serviceuser_v1.serviceuser_1.password
  region      = "ru-9"
}

Example file for connecting a private network to a DNS resolver

resource "openstack_networking_network_v2" "network_1" {
  name                  = "network"
  port_security_enabled = "true"
}

resource "openstack_networking_subnet_v2" "subnet_1" {
  name       = "subnet"
  network_id = openstack_networking_network_v2.network_1.id
  cidr       = "192.168.0.0/24"
}

resource "selectel_private_dns_service_v1" "service_1" {
  region     = openstack_networking_network_v2.network_1.region
  project_id = openstack_networking_network_v2.network_1.tenant_id
  network_id = openstack_networking_network_v2.network_1.id
}

1. Optional: configure providers

If you configured the Selectel and OpenStack providers, skip this step.

1. Make sure that in the control panel you have created a service user with the member roles in the Account scope and iam.admin.

2. Create a directory to store configuration files and a separate file with the .tf extension to configure providers.

3. Add the Selectel and OpenStack providers to the file for provider configuration:

   terraform {
     required_providers {
       selectel  = {
         source  = "selectel/selectel"
         version = "~> 7.1.0"
       }
       openstack = {
         source  = "terraform-provider-openstack/openstack"
         version = "2.1.0"
       }
     }
   }

   Here version is provider versions. You can check the current version in the Selectel documentation (in the Terraform Registry and GitHub) and OpenStack (in the Terraform Registry and GitHub).

   For more information about products, services, and features that can be managed using providers, see the Selectel and OpenStack Providers instructions.

4. Initialize the Selectel provider:

   provider "selectel" {
     domain_name = "123456"
     username    = "user"
     password    = "password"
     auth_region = "ru-9"
     auth_url    = "https://cloud.api.selcloud.ru/identity/v3/"
   }

   Where:

   • domain_name — Selectel account number. You can find it in the control panel in the upper-right corner;
   • username — name of the service user with the member roles in the Account scope and iam.admin. You can find it in the control panel: in the top menu, click IAM → Service Users (the section is available only to the Account Owner and a user with the iam.admin role);
   • password — password of the service user. You can view it when creating the user or change it to a new one;
   • auth_region — pool for authorization in the ru-9 format; do not use pools in the SPB-2 format. The pool for authorization may differ from the pool where you create resources. You can check the list of available pools in the Product Availability by Location instructions.

5. Create a project:

   resource "selectel_vpc_project_v2" "project_1" {
     name = "project"
   }

   See the detailed description of the selectel_vpc_project_v2 resource.

6. Create a service user to access the project and assign them the member role in the Project scope:

   resource "selectel_iam_serviceuser_v1" "serviceuser_1" {
     name         = "username"
     password     = "password"
     role {
       role_name  = "member"
       scope      = "project"
       project_id = selectel_vpc_project_v2.project_1.id
     }
   }

   Where:

   • username — username;

   • password — user password. The password must be at least 20 characters long and include at least:

     • one uppercase and one lowercase Latin letter (A-Z, a-z);
     • one digit (0-9);
     • one special character from the ASCII Printable 7-Bit Special Characters list:
       !"#$%&'()*+,-./:;<=>?@[]^_{|}~;

   • project_id — project ID. You can find it in the control panel: in the top menu, click IAM → Projects → in the row of the desired project, click .

   See the detailed description of the selectel_iam_serviceuser_v1 resource.

7. Initialize the OpenStack provider:

   provider "openstack" {
     auth_url    = "https://cloud.api.selcloud.ru/identity/v3"
     domain_name = "123456"
     tenant_id   = selectel_vpc_project_v2.project_1.id
     user_name   = selectel_iam_serviceuser_v1.serviceuser_1.name
     password    = selectel_iam_serviceuser_v1.serviceuser_1.password
     region      = "ru-9"
   }

   Where:

   • domain_name — Selectel account number. You can find it in the control panel in the upper-right corner;
   • region — pool, for example, ru-9. All resources will be created in this pool. You can check the list of available pools in the Product Availability by Location instructions.

8. If you create resources at the same time as configuring providers, add the depends_on argument for OpenStack resources. For example, for the openstack_networking_network_v2 resource:

   resource "openstack_networking_network_v2" "network_1" {
     name           = "private-network"
     admin_state_up = "true"
   
     depends_on = [
       selectel_vpc_project_v2.project_1,
       selectel_iam_serviceuser_v1.serviceuser_1
     ]
   }

9. Optional: if you want to use a mirror, create a separate Terraform CLI configuration file and add the following block to it:

   provider_installation {
     network_mirror {
       url = "https://tf-proxy.selectel.ru/mirror/v1/"
       include = ["registry.terraform.io/*/*"]
     }
     direct {
       exclude = ["registry.terraform.io/*/*"]
     }
   }

   For more information about mirror settings, see the CLI Configuration File instructions in the HashiCorp documentation.

10. Open the CLI.

11. Initialize the Terraform configuration in the directory:

    terraform init

12. Verify that the configuration files are syntactically correct:

    terraform validate

13. Format the configuration files:

    terraform fmt

14. Check which resources will be created:

    terraform plan

15. Apply the changes and create the resources:

    terraform apply

16. Confirm the creation — enter yes and press Enter. The created resources will appear in the control panel.

17. If there are not enough quotas to create resources, increase quotas.

2. Create a private network and subnet

resource "openstack_networking_network_v2" "network_1" {
  name           = "private-network"
  admin_state_up = "true"
}

resource "openstack_networking_subnet_v2" "subnet_1" {
  name       = "private-subnet"
  network_id = openstack_networking_network_v2.network_1.id
  cidr       = "192.168.199.0/24"
}

Here, cidr is the CIDR of the private subnet, for example, 192.168.199.0/24.

See the detailed resource description:

• openstack_networking_network_v2;
• openstack_networking_subnet_v2.

3. Connect the network to the DNS resolver

resource "selectel_private_dns_service_v1" "service_1" {
  region     = openstack_networking_network_v2.network_1.region
  project_id = openstack_networking_network_v2.network_1.tenant_id
  network_id = openstack_networking_network_v2.network_1.id
}

See the detailed description of the selectel_private_dns_service_v1 resource.

4. Specify the DNS resolver IP addresses in the subnet settings

You can specify the DNS resolver IP addresses in the subnet settings using the Control Panel or OpenStack CLI. Follow the Change DNS servers on private subnet section in the Private networks and subnets instructions.

The DNS resolver IP addresses in the network can be viewed in the Control Panel: in the top menu, click Products → Cloud Servers → Private DNS → the DNS resolvers tab → the network row → the DNS resolver field.