Examkin

Question

Difficulty: EasyNetworking and Connectivity Design

An administrator is setting up a two-tier application in a new VPC across two Availability Zones (AZ-A and AZ-B). The application servers reside in private subnets and must access the internet to download software updates. Which of the following network configuration steps should the solutions architect perform to ensure highly available and resilient outbound internet access for the private subnets? (Select TWO.)

  1. Deploy a NAT Gateway in the public subnet of Availability Zone A and another NAT Gateway in the public subnet of Availability Zone B.Answer
  2. Configure the route table for the private subnet in Availability Zone A to route traffic destined for 0.0.0.0/00.0.0.0/0 to the NAT Gateway in Availability Zone A, and do the same for Availability Zone B using its respective NAT Gateway.Answer
  3. C
    Deploy a single NAT Gateway in the public subnet of Availability Zone A, and configure the route tables of private subnets in both Availability Zones to target this NAT Gateway.
  4. D
    Create an AWS Transit Gateway, attach it to the VPC, and add a route in the private subnet route tables pointing 0.0.0.0/00.0.0.0/0 to the Transit Gateway to handle direct internet routing.
  5. E
    Associate a Route 53 Private Hosted Zone with the Internet Gateway to enable the private subnets to resolve external internet domains directly.

Answer

To ensure highly available outbound internet access, deploy a NAT Gateway in the public subnet of each Availability Zone, and configure the private subnet route tables to direct internet-bound traffic to their local NAT Gateway.
Deploying a NAT Gateway in each Availability Zone and configuring local routing ensures that an outage in one zone does not impact the other zone's ability to reach the internet. This setup removes single points of failure and maintains high availability for outbound traffic.

Step-by-Step Solution

1
Determine the requirement for high availability across multiple Availability Zones.
Identify that a single NAT Gateway represents a single point of failure if its Availability Zone experiences an outage.
To design a resilient system, components should be distributed across multiple Availability Zones.
2
Configure routing for each private subnet to keep traffic local to its Availability Zone.
Define route table entries that direct outbound traffic (0.0.0.0/00.0.0.0/0) to the NAT Gateway within the same Availability Zone.
This avoids cross-AZ traffic charges and prevents one AZ's failure from impacting the other's internet access.

Key Concept

High availability in AWS networking requires deploying redundant gateways (like NAT Gateways) across multiple Availability Zones and configuring route tables to avoid cross-AZ dependencies for external access.
Rate this question

Topics

Networking and Connectivity Design

More questions from this topic