DOP-C02 Resilient Cloud Solutions Practice Question
A company runs a critical application on AWS using Amazon EC2 instances in an Auto Scaling group, an Application Load Balancer (ALB), and an Amazon RDS for PostgreSQL Multi-AZ DB cluster. The application must maintain an RTO of 5 minutes and an RPO of 1 second for database transactions. The current setup meets these requirements, but the DevOps team wants to improve the resilience of the application tier to withstand a regional failure. Which THREE actions should be taken? (Choose three.)
⚠ Common exam trap
Watch out — candidates often confuse Multi-AZ with cross-region disaster recovery, assuming Multi-AZ alone provides regional failover, when in fact it only protects against Availability Zone failures within a single region.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Replace the RDS Multi-AZ cluster with Amazon Aurora Global Database to replicate data across regions.
Amazon Aurora Global Database is the correct choice because it provides cross-region replication with a typical RPO of 1 second and RTO of 1 minute, meeting the stated requirements. Unlike standard RDS Multi-AZ, which is limited to a single region, Aurora Global Database replicates data asynchronously across multiple regions with minimal lag, ensuring the database tier can survive a regional failure while maintaining the required RPO of 1 second.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Replace the RDS Multi-AZ cluster with Amazon Aurora Global Database to replicate data across regions.
Why this is correct
RDS Multi-AZ only synchronously replicates to a standby in the same Region, so it cannot protect against a regional outage. Amazon Aurora Global Database replicates data to up to five secondary Regions using storage-level replication, typically with an RPO of 1 second or less, while still providing a familiar MySQL/PostgreSQL-compatible endpoint. Promoting a secondary Region during failover is a fast, deliberate action that preserves the database's durability and availability in a disaster recovery scenario.
- ✓
Use an active-passive architecture with a second Auto Scaling group and ALB in another region.
Why this is correct
An active-passive architecture with a second Auto Scaling group and Application Load Balancer in another Region is a classic warm standby pattern: you pre-provision compute capacity in the secondary Region with the same configuration and scaling policies, but it does not serve traffic until failover occurs. The secondary ALB remains available to accept traffic when DNS is switched. This approach minimizes RTO because infrastructure is already running, but it does incur standby compute costs; it must be combined with cross-Region data replication to be effective.
- ✗
Use Amazon EFS Replication to replicate application data across regions with a recovery point objective (RPO) of 1 second.
Why it's wrong here
Amazon EFS Replication does replicate file data asynchronously to a destination Region, but it does not guarantee a 1-second RPO—backup replication lag is typically minutes, not seconds. More importantly, EFS is for file storage, not relational databases, so it cannot replicate the application's RDS database content or transactions. This option would leave the database without cross-Region replication, so it fails the core DR requirement.
- ✗
Extend the existing Auto Scaling group to launch instances in two regions by specifying a second region in the launch template.
Why it's wrong here
An Auto Scaling group is a Regional resource—it can only launch instances in the subnets and Availability Zones of the single AWS Region in which the group exists. A launch template can only specify one Region's AMI and network settings; you cannot specify a second Region. To run compute in another Region, you must create a separate Auto Scaling group in that Region and then coordinate failover through DNS, so this option is not technically implementable as stated.
- ✓
Set up Amazon Route 53 with health checks and failover routing policy to direct traffic to the secondary region if the primary fails.
Why this is correct
Route 53 failover routing with health checks is the correct traffic management mechanism to redirect users from a failed primary to a secondary Region's endpoint. Health checks continuously verify the primary's ALB or endpoint; once unhealthy, DNS responses automatically switch to the secondary record. However, Route 53 only handles traffic routing—it does not replicate application data, so it must be used alongside cross-Region database replication (e.g., Aurora Global Database) and a standby compute stack to provide a complete disaster recovery solution.
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Same concept, more angles
1 more way this is tested on DOP-C02
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A company runs a critical application on Amazon EC2 instances in an Auto Scaling group. To ensure high availability, the instances are deployed across three Availability Zones. Which additional step should the company take to protect against a regional failure?
easy- A.Place all instances in a single Availability Zone to simplify management.
- B.Use EC2 Dedicated Hosts to ensure capacity.
- C.Increase the minimum size of the Auto Scaling group to 10 instances.
- ✓ D.Deploy the application in a second AWS Region and use Route 53 with failover routing.
Why D: Deploying the application in a second AWS Region and using Route 53 with failover routing protects against a regional failure by redirecting traffic to the healthy region. Option A is incorrect because placing all instances in a single Availability Zone reduces availability and does not protect against regional failure. Option B is incorrect because EC2 Dedicated Hosts provide dedicated physical servers for licensing or compliance requirements, not regional resilience. Option C is incorrect because increasing the minimum size of the Auto Scaling group only affects capacity within the current region and does not mitigate a regional outage.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DOP-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DOP-C02 exam.