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Zorluk: OrtaHigh Availability and Disaster Recovery Design

A digital publishing company is designing a disaster recovery (DR) architecture for its high-traffic content management application. The primary database is an Amazon RDS for PostgreSQL instance. The application tier runs on Amazon EC2 instances behind an Application Load Balancer (ALB). The business requirements specify a Recovery Time Objective (RTO) of less than 1515 minutes and a Recovery Point Objective (RPO) of less than 55 minutes. Additionally, the secondary database must be capable of serving read-only search queries to local users in the secondary region during normal operations to offload read traffic. The solution must also support internal service discovery using a Route 53 Private Hosted Zone (PHZ). Which two actions should the solutions architect take to meet these requirements?

  1. Create a cross-region read replica of the RDS for PostgreSQL instance in the secondary region. Configure the local search application in the secondary region to query this replica for read-only traffic, and promote it to a standalone primary instance during a failover.Cevap
  2. Configure Amazon Route 53 with a Failover routing policy. Point the primary record to the primary ALB and the secondary record to an ALB in the secondary region, where an Auto Scaling group is pre-deployed with a minimum capacity of 11 instance to process local read-only traffic.Cevap
  3. C
    Enable Amazon RDS Multi-AZ in the primary region, and configure the local search application in the secondary region to route its read-only queries to the synchronous Multi-AZ standby instance to offload read traffic.
  4. D
    Implement an AWS Backup plan that takes daily RDS and EBS snapshots in the primary region, copies them to the secondary region, and uses AWS CloudFormation to restore the database and instances only when a failover is triggered.
  5. E
    In the secondary region, route outbound internet traffic from the private subnets in all Availability Zones through a single NAT Gateway deployed in a single public subnet to minimize running costs during standby operations.
  6. F
    For internal service discovery between the application components, utilize the existing Route 53 Private Hosted Zone (PHZ) in the primary VPC, relying on Transit Gateway peering to automatically resolve internal DNS queries in the secondary VPC without associating the PHZ.

Cevap

Create a cross-region read replica of the RDS for PostgreSQL instance, and configure Amazon Route 53 with a Failover routing policy pointing to a pre-deployed standby ALB with an Auto Scaling group in the secondary region.
The correct solution uses an Amazon RDS cross-region read replica, which provides asynchronous database replication with low lag (meeting the 55-minute RPO) and supports active read queries from local applications. For the application tier, configuring Route 53 Failover routing health-checked against the primary ALB allows automated traffic redirection to the secondary region. Pre-deploying the Auto Scaling group with a minimum capacity of 11 instance ensures the standby resources are online to serve local search queries and can scale out immediately during failover, satisfying the 1515-minute RTO constraint.

Adım Adım Çözüm

1
Establish database replication to satisfy RPO and read-only traffic requirements.
A cross-region Amazon RDS Read Replica is created in the secondary region, which replicates data asynchronously under 55 minutes and can be queried directly.
RDS Read Replicas support cross-region asynchronous replication with low lag and support active read workloads, satisfying both the RPO and the local query requirement.
2
Configure public routing and compute resources for disaster recovery.
Route 53 Failover routing redirects traffic to the secondary ALB, where an Auto Scaling group with a minimum capacity of 11 instance is pre-deployed.
A warm standby configuration with a scaled-down application tier ensures the secondary site is online to serve local read-only traffic and can quickly scale out to meet the 1515-minute RTO during failover.
3
Ensure internal DNS resolution is functional across regions.
The Route 53 Private Hosted Zone created in the primary VPC is associated with the secondary VPC.
Private Hosted Zones must be explicitly associated with each VPC that needs to resolve its records, as network connectivity alone does not enable DNS resolution.

Anahtar Kavram

Designing a multi-region active-passive disaster recovery architecture using RDS cross-region read replicas and Route 53 failover routing policies, while ensuring proper VPC DNS association and multi-AZ NAT redundancy.
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Konular

High Availability and Disaster Recovery Design

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