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Zorluk: KolayEnhancing Reliability and Disaster Recovery

A company runs a business-critical application on Amazon EC2 instances in private subnets across three Availability Zones (AZs) in a single VPC. Currently, all outbound internet traffic from the private subnets is routed through a single NAT Gateway located in public subnet A. To improve the reliability of the system, a solutions architect must eliminate the single point of failure in the outbound traffic path.

Which configuration change should the solutions architect implement to meet this reliability requirement?

  1. Deploy a NAT Gateway in the public subnet of each Availability Zone, and configure the route table of the private subnets in each Availability Zone to route outbound traffic through the local NAT Gateway in the same zone.Cevap
  2. B
    Deploy a second NAT Gateway in public subnet A, and configure an Amazon Route 53 Failover routing policy to distribute outbound traffic between the two NAT Gateways based on health checks.
  3. C
    Deploy a NAT Instance in public subnet B, associate the instance's IP address with a Route 53 Private Hosted Zone, and point the private subnets' route tables to the hosted zone domain.
  4. D
    Configure an AWS Lambda function to monitor the health of the single NAT Gateway and automatically migrate the NAT Gateway to a public subnet in a different Availability Zone if a failure is detected.

Cevap

Deploy a NAT Gateway in the public subnet of each Availability Zone, and configure the route table of the private subnets in each Availability Zone to route outbound traffic through the local NAT Gateway in the same zone.
Deploying a NAT Gateway in each Availability Zone and routing the traffic from each zone's private subnets through its local NAT Gateway aligns with the AWS Well-Architected recommendation for achieving zone-level high availability and reliability for outbound traffic.

Adım Adım Çözüm

1
Analyze the current architecture and identify the single point of failure.
The current setup uses a single NAT Gateway in public subnet A (in one Availability Zone) to serve outbound traffic for private subnets across all three Availability Zones. If the Availability Zone containing the NAT Gateway goes down, all outbound internet traffic from all private subnets will fail.
Understanding the failure domain of the current network setup is necessary to propose a high-availability design.
2
Select a highly available and redundant NAT architecture.
Deploy one NAT Gateway in the public subnet of each Availability Zone (three NAT Gateways in total) and ensure the private subnets in each zone route their outbound traffic to the local NAT Gateway in the same zone.
This isolates Availability Zone failures so that an outage in one zone does not impact the outbound connectivity of resources in the other zones.

Anahtar Kavram

Multi-AZ NAT Gateway Redundancy
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Enhancing Reliability and Disaster Recovery