Review NAT gateway cost for the declared environment

What it checks

NAT Gateway: this tagged gateway bills hourly and for data processed.

Where it applies

Terraform: aws_nat_gateway

CloudFormation: AWS::EC2::NatGateway

How to fix it

1. If not already present, assess S3 and DynamoDB gateway endpoints for compatible routes; these gateway endpoints have no additional endpoint charge. Interface endpoints for services such as ECR, KMS, Secrets Manager and STS bill per provisioned Availability Zone hour and data processing. Compare total costs and existing endpoints first.
2. If general internet egress remains necessary, compare a NAT instance using measured traffic and availability needs. Instances require sizing, patching, source/destination-check configuration, connection monitoring and scripted failover between instances. That failover requirement describes NAT instances, not NAT gateways; do not assume an instance is always cheaper.

Frameworks

• AWS Well-Architected COST.6

These mappings are advisory, not an attestation of compliance.

Vendor documentation

All rules