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

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

We recommend creating resources in order. If you create all resources at once, Terraform will account for 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 instance, a resource required for creating another resource might not have been created yet.


  1. Optional: configure the 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 have already configured the providers for Selectel and OpenStack, skip this step.

  1. Make sure that in the control panel you have created a service user with the member role in the Account access 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 the provider version. The current version can be found in the Selectel documentation (in Terraform Registry and GitHub) and OpenStack (in Terraform Registry and GitHub).

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

  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 top-right corner;
    • username — name of the service user with the member role in the Account access scope and iam.admin. You can view it in the control panel: in the top menu, click IAM → Service Users section (the section is only available to the Account Owner and a user with the iam.admin role);
    • password — service user password. You can view it when creating the user or change it to a new one;
    • auth_region — pool for authorization, for example, ru-9. You can create resources in other pools. A list of available pools can be found in the Availability Matrix guide.

  5. Create a project:

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

    See a 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 access 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 Products and select Cloud Servers → open the projects menu → in the row of the target project, click .

    See a 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 top-right corner;
    • region — pool, for example, ru-9. All resources will be created in this pool. A list of available pools can be found in the Availability Matrix guide.

  8. If you are creating resources while 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/*/*"]
      }
    }

    Read more about mirror settings in the CLI Configuration File guide 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 creation — enter yes and press Enter. The created resources will appear in the control panel.

  17. If quotas were insufficient to create the resources, increase the 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 private subnet CIDR, for example 192.168.199.0/24.

See the detailed resource description:

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 resource description selectel_private_dns_service_v1.

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

You can specify the DNS resolver IP addresses in the subnet settings via the Control Panel or OpenStack CLI. Use the Change DNS servers in a private subnet subsection of the Private networks and subnets guide.

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