r/aws_networkmanager_core_network: Support multiple regions in the base policy

[GlennChia]

Description

For VPC Attachments to be used with Core Networks, a Policy Document with the region that the VPC is created in is required. Currently the aws_networkmanager_core_network resource only supports specifying one region via the base_policy_region argument. This means that the first Terraform apply will only work with VPCs in one region. There could be a use-case that involves multi-region.

Proposed fix

1. Introduce a new argument base_policy_regions that allow users to specify multiple regions in the base policy
2. This also involves refactoring how the base policy is constructed. An idea is to use the the structs that are also used in the aws_networkmanager_core_network_policy_document data source to help format the policy
3. Deprecate the base_policy_region argument

Relates #28867

Affected Resource(s) and/or Data Source(s)

• aws_networkmanager_core_network

Potential Terraform Configuration

resource "aws_networkmanager_global_network" "example" {}

data "aws_networkmanager_core_network_policy_document" "example" {
  core_network_configuration {
    asn_ranges = ["65022-65534"]

    edge_locations {
      location = "us-west-2"
    }

    edge_locations {
      location = "us-east-1"
    }
  }

  segments {
    name = "segment"
  }

  segments {
    name = "segment2"
  }

  segment_actions {
    action  = "create-route"
    segment = "segment"
    destination_cidr_blocks = [
      "10.0.0.0/16"
    ]
    destinations = [
      aws_networkmanager_vpc_attachment.example_us_west_2.id,
    ]
  }

  segment_actions {
    action  = "create-route"
    segment = "segment"
    destination_cidr_blocks = [
      "10.1.0.0/16"
    ]
    destinations = [
      aws_networkmanager_vpc_attachment.example_us_east_1.id,
    ]
  }
}

resource "aws_networkmanager_core_network" "example" {
  global_network_id  = aws_networkmanager_global_network.example.id
  base_policy_regions = ["us-west-2", "us-east-1"]
  create_base_policy = true
}

resource "aws_networkmanager_core_network_policy_attachment" "example" {
  core_network_id = aws_networkmanager_core_network.example.id
  policy_document = data.aws_networkmanager_core_network_policy_document.example.json
}

resource "aws_networkmanager_vpc_attachment" "example_us_west_2" {
  core_network_id = aws_networkmanager_core_network.example.id
  subnet_arns     = aws_subnet.example_us_west_2[*].arn
  vpc_arn         = aws_vpc.example_us_west_2.arn
}

resource "aws_networkmanager_vpc_attachment" "example_us_east_1" {
  provider = "alternate"

  core_network_id = aws_networkmanager_core_network.example.id
  subnet_arns     = aws_subnet.example_us_east_1[*].arn
  vpc_arn         = aws_vpc.example_us_east_1.arn
}

References

PR that introduced the create_base_policy and base_policy_region arguments in aws_networkmanager_core_network: #29097

Would you like to implement a fix?

Yes

[github-actions]

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[github-actions]

This functionality has been released in v4.57.0 of the Terraform AWS Provider. Please see the Terraform documentation on provider versioning or reach out if you need any assistance upgrading.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template. Thank you!

[github-actions]

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