Ensure Proper Failover in AWS Architecture

Answer - D.

The AWS Documentation mentions the following.

You can create an active-passive failover configuration by using failover records.

You create a primary and a secondary failover record with the same name and type, and you associate a health check with each.

For more information on DNS failover using Route53, please visit the following URL:

The correct answer to this question is D. Configure a failover routing policy.

In this architecture, there are two infrastructures, a primary and a secondary one, both consisting of Elastic Load Balancers (ELB), Auto Scaling Groups (ASG), and EC2 instances. In the event of a failure of the primary infrastructure, Route53 must be configured to ensure that traffic is automatically routed to the secondary infrastructure.

A failover routing policy is the best option for this scenario. A failover routing policy is used to automatically route traffic to a secondary resource when the primary resource becomes unavailable. In this case, the primary resource is the primary infrastructure, and the secondary resource is the secondary infrastructure.

To configure a failover routing policy, follow these steps:

1. Create two resource record sets (RRsets) in Route53: one for the primary infrastructure and one for the secondary infrastructure.

2. Assign a health check to each RRset. The health check should check the health of the ELB associated with each infrastructure.

3. Create a failover routing policy for the primary RRset that points to the primary infrastructure. The policy should be set to "Primary" and should be associated with the health check for the primary infrastructure.

4. Create a failover routing policy for the secondary RRset that points to the secondary infrastructure. The policy should be set to "Secondary" and should be associated with the health check for the secondary infrastructure.

With this configuration, Route53 will monitor the health of the ELBs associated with each infrastructure. If the primary infrastructure fails, Route53 will automatically switch traffic to the secondary infrastructure. Once the primary infrastructure is healthy again, Route53 will switch traffic back to the primary infrastructure.

Note that a weighted routing policy (B) is used to distribute traffic across multiple resources based on a weight assigned to each resource. This policy is not appropriate for this scenario because we want to route traffic to a single resource (either the primary or the secondary infrastructure).

A multi-answer routing policy (C) is used to route traffic to multiple resources at the same time. This policy is not appropriate for this scenario because we want to route traffic to a single resource (either the primary or the secondary infrastructure).

A primary routing policy (A) is used to route all traffic to a single resource. This policy is not appropriate for this scenario because we want to route traffic to the secondary infrastructure if the primary infrastructure fails.