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Zorluk: KolayNetworking and Connectivity Design

A company is designing a new web application in a single VPC across two Availability Zones: us-east-1a and us-east-1b. The application consists of web servers in public subnets and database servers in private subnets. The database servers must download software patches from the internet, and the design must remain resilient to a single Availability Zone outage. Which configuration meets these requirements?

  1. Deploy one NAT Gateway in the public subnet of us-east-1a and another NAT Gateway in the public subnet of us-east-1b. Configure the route table of the private subnet in each Availability Zone to route outbound internet traffic through the local NAT Gateway in that same zone.Cevap
  2. B
    Deploy a single NAT Gateway in the public subnet of us-east-1a. Configure the route tables of the private subnets in both us-east-1a and us-east-1b to route outbound internet traffic through this single NAT Gateway.
  3. C
    Deploy one NAT Gateway in the public subnet of us-east-1a. Create a Route 53 Private Hosted Zone for the patch repositories and associate it with both us-east-1a and us-east-1b private subnets to load-balance traffic between zones.
  4. D
    Deploy a single Direct Connect Gateway and establish a private virtual interface. Configure the route tables of the private subnets to route outbound internet traffic transitively through the Direct Connect Gateway directly to the internet.

Cevap

Deploy one NAT Gateway in the public subnet of us-east-1a and another NAT Gateway in the public subnet of us-east-1b, configuring each private subnet to use its local NAT Gateway.
The correct answer is to deploy a NAT Gateway in the public subnet of each Availability Zone (us-east-1a and us-east-1b) and configure the local private subnets to point their outbound route (0.0.0.0/00.0.0.0/0) to the local NAT Gateway. Since NAT Gateways are redundant within a single Availability Zone but do not span multiple zones, having one in each zone ensures that an outage in one zone does not affect outbound connectivity for the other zone.

Adım Adım Çözüm

1
Analyze the requirements for outbound internet connectivity and high availability across multiple Availability Zones.
Identified that database servers in private subnets must reach the internet, and the solution must tolerate a single Availability Zone outage.
This establishes the need for redundant NAT Gateways to avoid a single point of failure.
2
Evaluate the NAT Gateway placement strategy for multi-AZ resiliency.
A NAT Gateway is a zonal resource; therefore, to ensure high availability, a NAT Gateway must be deployed in each Availability Zone.
If a single NAT Gateway is used and its Availability Zone fails, all other zones lose outbound internet access.
3
Configure the VPC route tables to direct outbound traffic (0.0.0.0/00.0.0.0/0) to the corresponding local NAT Gateway.
The private subnet in us-east-1a routes to the NAT Gateway in us-east-1a, and the private subnet in us-east-1b routes to the NAT Gateway in us-east-1b.
This keeps traffic within the same Availability Zone, reducing inter-AZ data transfer costs and ensuring zone independence.

Anahtar Kavram

Multi-Availability Zone NAT Gateway Redundancy
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Konular

Networking and Connectivity Design

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