Examkin

Question

Difficulty: MediumHigh Availability and Disaster Recovery Design

A public transit authority is designing a contactless ticketing system on AWS. The application tier runs on Amazon EC2 instances in an Auto Scaling group behind an Application Load Balancer (ALB) in the primary AWS Region. The database tier uses an Amazon Aurora PostgreSQL DB cluster. The application must communicate with external payment processors via the internet. The solution must be highly available within the primary AWS Region and have a cross-region disaster recovery (DR) plan with a Recovery Time Objective (RTO) of 15 minutes and a Recovery Point Objective (RPO) of 5 minutes. Compute costs in the DR region should be minimized during normal operations. Which combination of actions will meet these requirements? (Select TWO.)

  1. Configure Amazon Aurora Global Database with the primary cluster in the primary region and a secondary cluster in the DR region. Pre-create the Application Load Balancer and an Auto Scaling group in the DR region with desired capacity set to 0, scaling it up to handle traffic only during a failover event.Answer
  2. In both the primary and DR regions, deploy the subnet architecture across multiple Availability Zones, provision a NAT gateway in each public subnet, and configure the private subnet route tables to route outbound internet traffic to the local NAT gateway in the same Availability Zone.Answer
  3. C
    Configure multi-region database replication by deploying an Amazon Aurora DB cluster in the primary region and setting up Amazon RDS Multi-AZ standby instances in the DR region, configuring Aurora Auto Scaling on the standby instances to dynamically handle write workloads during failover.
  4. D
    Deploy a single NAT gateway in a public subnet in the primary region, and update the route tables of the DR region's private subnets to route outbound traffic through an inter-region VPC peering connection to this single NAT gateway.
  5. E
    Use Route 53 Geolocation routing to direct traffic, and associate a Route 53 Private Hosted Zone with the VPCs in both regions, relying on external Route 53 health checks to automatically fail over the internal DNS records to the DR region during an outage.

Answer

Configure Amazon Aurora Global Database with the primary cluster in the primary region and a secondary cluster in the DR region, pre-creating the Application Load Balancer and an Auto Scaling group in the DR region with desired capacity set to 0. Additionally, deploy the subnet architecture across multiple Availability Zones in both regions, provisioning a NAT gateway in each public subnet, and configure the private subnet route tables to route outbound internet traffic to the local NAT gateway in the same Availability Zone.
The correct architecture uses Amazon Aurora Global Database to achieve cross-region disaster recovery with near-zero replication lag, satisfying the RPO and RTO requirements. To minimize compute costs in the disaster recovery region, the Auto Scaling group capacity is set to 0 and only scaled up when a failover is initiated. For high availability of outbound internet traffic to external payment processors, deploying a NAT gateway in each Availability Zone in both regions prevents a single Availability Zone outage from disrupting outbound communication.

Step-by-Step Solution

1
Determine the database replication strategy that satisfies the RPO of 5 minutes and RTO of 15 minutes.
Amazon Aurora Global Database provides sub-second replication and quick failover capabilities, which easily meets the RPO and RTO requirements.
An active-passive replication model using Aurora Global Database keeps the secondary cluster synchronized with minimal lag.
2
Address the requirement to minimize compute costs in the disaster recovery region.
Set the EC2 Auto Scaling group desired capacity to 0 in the secondary region during normal operations.
This avoids paying for EC2 instances while the secondary region is passive, and allows scaling up only during a failover event.
3
Design the outbound internet connectivity for external payment processing to ensure high availability.
Deploy NAT gateways in multiple Availability Zones in the primary and secondary regions, pointing the private subnet route tables to the NAT gateway in the same Availability Zone.
Deploying a NAT gateway per Availability Zone ensures that an outage in one zone does not impact the outbound connectivity of instances running in other zones.

Key Concept

High Availability and Multi-Region Active-Passive Disaster Recovery Design
Rate this question

Topics

High Availability and Disaster Recovery Design

More questions from this topic