How do I optimize costs for Route 53 resolver endpoints?

Short description

Route 53 Resolver endpoints primarily answer DNS queries between AWS environments and on-premises networks. To forward DNS queries to or from your on-premises network, create outbound and inbound endpoints, depending on your use case.

Note: Route 53 Resolver endpoints are specific to AWS Region.

For both inbound and outbound endpoints, specify IP addresses for where you want to send or receive DNS queries. For each of these IP addresses, Route 53 Resolver automatically creates an elastic network interface (ENI). Each elastic network interface is billed for $0.125 per hour.

In addition to elastic network interface costs, Route 53 charges you for DNS queries that pass through these inbound and outbound endpoints:

• For queries up to one billion per month: $0.40 per million queries
• For queries after the first billion per month: $0.20 per million queries

Therefore, for single inbound or outbound Resolver endpoints with two IP address, the minimum monthly cost is approximately $182.50.

To save costs with your Resolver endpoints, implement any of the following methods that fit your use case:

• Share Resolver rules and outbound endpoints.
• Increase TTL values on DNS records.
• Associate VPCs with Private Hosted Zones:.

Resolution

Share Resolver rules and outbound endpoints

You can share a single outbound endpoint with multiple virtual private clouds (VPCs) across different accounts, as long as those VPCs exist in the same Region. This incurs no additional charges. If you configure multiple outbound endpoints with multiple VPCs, then you incur additional charges. To reduce costs, consolidate your endpoints rather than using individual endpoints. For more information, see Simplify DNS management in a multi-account environment with Route 53 Resolver.

Note: Route 53 Resolver has limit of 10,000 queries per second per IP address on an endpoint. If you anticipate higher query volumes, then add more ENIs as needed. However, additional ENIs incur higher costs.

Increase TTL values on DNS records

To indirectly reduce costs, increase the TTL value for your records. This increases the time interval that a DNS resolver queries Route 53 for the current values of your record. An increased TTL value decreases the number of calls that DNS recursive resolvers make through Route 53. Because you incur charges for recursive DNS queries to and from on-premises networks for each query, this reduces overall costs.

Note: Longer TTL values increase the chances that Resolvers notice any new changes to your records in Hosted Zones or DNS servers. Because of DNS caching on Resolver endpoints, this increases the chances that Route 53 returns stale DNS responses to you.

Associate VPCs with Private Hosted Zones

If you host all your architecture within AWS, then you can use private hosted zone associations instead of Resolver endpoints. You can resolve records in a private hosted zone from another VPC that's in the same account or a different account. This doesn't incur additional costs. See the Route 53 documentation on associating your VPCs and private hosted zone within the same AWS account or across different AWS accounts.