Support NAT Gateway Regional Mode #228
Description
Describe the Feature
https://aws.amazon.com/about-aws/whats-new/2025/11/aws-nat-gateway-regional-availability
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Amazon Web Services (AWS) announces regional availability mode for NAT Gateways. With this launch, you can create a single NAT Gateway that automatically expands and contracts across availability zones (AZs) in your Virtual Private Cloud (VPC) based on your workload presence, to maintain high availability while offering simplified setup and management.
A NAT Gateway enables instances in a private subnet to connect to services outside your VPC using the NAT Gateway's IP address. With this launch, you can create a NAT Gateway and set its availability to regional. You do not need a public subnet to host a regional NAT Gateway. You also do not have to create and delete NAT Gateways, and edit your route tables every time your workloads expand to new availability zones. You simply create a NAT Gateway with regional mode, choose your VPC, and it automatically expands and contracts across all availability zones based on your workload's presence, maintaining high availability. You can use this feature with Amazon provided IP addresses or bring your own IP addresses.
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Expected Behavior
Currently it has to specify subnets and such. But now, "you no longer need Public Subnets, or to configure each private subnet’s route table to egress via the respective NatGW in the same AZ. Instead, you just point the private route table to the Regional NatGW, and AWS handles the rest."
This is available in the Terraform provider via availability_mode, where it can be specified to be "regional" or "zonal"
Use Case
It becomes even more managed service.
Describe Ideal Solution
This is likely a breaking MAJOR semantic version change.
Alternatives Considered
No response
Additional Context
No response