This PR defines a separate NAT gateway for each AZ in the VPC alongside its respective route table. Egress traffic sourced from all private subnets and destined for the Internet route traffic to the Internet by using the NAT gateway located in the same AZ as the source subnet.
The current default configuration creates a single point of failure from all AZ's onto AZ1 for egress traffic. If AZ1 goes offline, so do all the other AZ's that route through AZ1 (at least for egress to the Internet).
A potential byproduct of this change is consuming additional Elastic IPs which could exceed the default AWS account limits.
This PR defines a separate NAT gateway for each AZ in the VPC alongside its respective route table. Egress traffic sourced from all private subnets and destined for the Internet route traffic to the Internet by using the NAT gateway located in the same AZ as the source subnet.
The current default configuration creates a single point of failure from all AZ's onto AZ1 for egress traffic. If AZ1 goes offline, so do all the other AZ's that route through AZ1 (at least for egress to the Internet).
A potential byproduct of this change is consuming additional Elastic IPs which could exceed the default AWS account limits.