TerraformでAmazon Route 53を構築するサンプルコードを書いてみた

# Requirements
terraform {
  required_version = "~> 1.3.6"

  required_providers {
    aws = {
      source  = "hashicorp/aws"
      version = "~> 4.46.0"
    }
  }
}

# デフォルトのプロバイダー設定
provider "aws" {
  region = var.aws_region
  default_tags {
    tags = {
      Owner     = "matt"
      Terraform = "true"
    }
  }
}

# プライベートDNSゾーンを共有する先のAWSアカウント情報
provider "aws" {
  alias  = "guest"
  region = var.aws_region
  assume_role {
    role_arn = var.iam_assume_role
  }
  default_tags {
    tags = {
      Owner     = "matt"
      Terraform = "true"
    }
  }
}

# プライベートDNSゾーンの定義
resource "aws_route53_zone" "this" {
  name = "example.com"

  # NOTE: The aws_route53_zone vpc argument accepts multiple configuration
  #       blocks. The below usage of the single vpc configuration, the
  #       lifecycle configuration, and the aws_route53_zone_association
  #       resource is for illustrative purposes (e.g. for a separate
  #       cross-account authorization process, which is not shown here).
  vpc {
    vpc_id = data.aws_vpc.primary.id
  }

  lifecycle {
    ignore_changes = [vpc]
  }
}

# VPC情報の取得
data "aws_vpc" "primary" {
  cidr_block = var.primary_vpc_cidr_block

  filter {
    name   = "tag:Name"
    values = [var.primary_vpc_name]
  }
}

# 別VPCへのプライベートDNSゾーンの関連付け
resource "aws_route53_zone_association" "this" {
  vpc_id  = data.aws_vpc.secondary.id
  zone_id = aws_route53_zone.this.id
}

# VPC情報の取得
data "aws_vpc" "secondary" {
  cidr_block = var.secondary_vpc_cidr_block

  filter {
    name   = "tag:Name"
    values = [var.secondary_vpc_name]
  }
}

# 別アカウント上のVPCへの割り当て承認
resource "aws_route53_vpc_association_authorization" "this" {
  vpc_id  = data.aws_vpc.guest.id
  zone_id = aws_route53_zone.this.id
}

# 別アカウント上のVPCへのプライベートDNSゾーンの関連付け
resource "aws_route53_zone_association" "this" {
  provider = aws.guest

  vpc_id  = data.aws_vpc.guest.id
  zone_id = aws_route53_zone.this.id
}

# VPC情報の取得
data "aws_vpc" "guest" {
  provider = aws.guest

  cidr_block = var.guest_vpc_cidr_block

  filter {
    name   = "tag:Name"
    values = [var.guest_vpc_name]
  }
}

# DNSレコードの定義
resource "aws_route53_record" "www" {
  zone_id = aws_route53_zone.this.zone_id
  name    = "www.example.com"
  type    = "A"
  ttl     = 300
  records = [aws_eip.alb.public_ip]
}

# DNSレコードの定義
resource "aws_route53_record" "www" {
  zone_id = aws_route53_zone.this.zone_id
  name    = "www.example.com"
  type    = "A"

  alias {
    name                   = aws_vpc_endpoint.this.dns_entry[0].dns_name
    zone_id                = aws_vpc_endpoint.this.dns_entry[0].hosted_zone_id
    evaluate_target_health = true
  }
}

# DNSレコードの定義
resource "aws_route53_record" "www" {
  zone_id = aws_route53_zone.this.zone_id
  name    = "www"
  type    = "CNAME"
  ttl     = 300
  records = ["www.example.co.jp"]
}