How to Get Route53 Hosted Zone Information in Terraform
This guide explains how to retrieve information about your Amazon Route53 hosted zones using Terraform. Knowing how to do this is crucial for managing your DNS infrastructure as code, ensuring consistency, and avoiding manual configuration. We'll cover several methods, each with its strengths and weaknesses.
Understanding the Challenge
Terraform excels at managing infrastructure, but directly accessing and displaying Route53 hosted zone details requires a specific approach. Route53 doesn't offer a single data source that provides all information; instead, you'll need to use a combination of data sources and potentially some clever string manipulation.
Method 1: Using aws_route53_zone Data Source (Recommended)
This is the most straightforward method for retrieving information about a specific hosted zone. You'll need the zone's name or ID.
Code Example:
data "aws_route53_zone" "selected" {
name = "example.com." # Replace with your zone's name, including the trailing dot.
}
output "zone_id" {
value = data.aws_route53_zone.selected.zone_id
}
output "name_servers" {
value = data.aws_route53_zone.selected.name_servers
}
output "comment" {
value = data.aws_route53_zone.selected.comment
}
Explanation:
data "aws_route53_zone" "selected": This defines a data source that fetches information from Route53."selected"is a descriptive name for this data source.name = "example.com.": Crucially, replace"example.com."with the fully qualified domain name (FQDN) of your hosted zone, including the trailing dot. This is essential for correct identification.output "zone_id",output "name_servers",output "comment": These blocks display specific attributes of the hosted zone. You can add more outputs as needed to retrieve other attributes likevpc_id(if the zone is associated with a VPC).
Pros: Simple and direct. Retrieves specific information efficiently. Cons: Requires knowing the zone's name. Doesn't list all zones; you must specify one.
Method 2: Listing All Hosted Zones and Filtering (For Multiple Zones)
If you need information about multiple zones or don't know the exact name in advance, you'll need to list all zones and then filter the results.
Code Example:
data "aws_route53_zones" "all" {}
output "zone_ids" {
value = [for zone in data.aws_route53_zones.all.zones : zone.zone_id]
}
output "zone_names" {
value = [for zone in data.aws_route53_zones.all.zones : zone.name]
}
# Example filtering (requires Terraform 0.12 or later):
output "specific_zone_id" {
value = tolist([for zone in data.aws_route53_zones.all.zones : zone.zone_id if contains(zone.name, "example.com.")])[0]
}
Explanation:
data "aws_route53_zones" "all": This data source retrieves all hosted zones in your AWS account.- The outputs iterate through the list of zones to extract specific attributes.
- The
specific_zone_idoutput demonstrates how to filter the results using list comprehensions (available in Terraform 0.12+).
Pros: Retrieves information about all zones. Allows filtering based on criteria. Cons: Can be less efficient if you only need information about a single zone. Requires more complex code for filtering.
Important Considerations
- AWS Credentials: Ensure your AWS credentials are properly configured for Terraform to access your Route53 account. This typically involves setting up environment variables or using an AWS profile.
- Error Handling: Implement robust error handling in your Terraform code to gracefully manage situations where a zone is not found.
- Trailing Dot: Remember the trailing dot in the zone name (e.g.,
example.com.) when usingaws_route53_zone. Its omission is a frequent source of errors.
By using these methods, you can effectively manage and retrieve your Route53 hosted zone information within your Terraform infrastructure-as-code deployments. Remember to adapt the code examples to your specific needs and always prioritize secure access to your AWS resources.
