← DOP-C02·Amazon Web Services

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Resilient Cloud Solutions →mediumMultiple ChoiceObjective-mapped

Quick Answer

The answer is to use Amazon RDS Proxy with the RDS cluster endpoint, as this directly reduces failover recovery time by maintaining a warm connection pool. When a Multi-AZ failover occurs, RDS Proxy automatically redirects existing connections to the new primary DB instance, eliminating the need for the application to re-establish connections and avoiding the connection storm that causes several minutes of downtime. On the AWS Certified DevOps Engineer Professional DOP-C02 exam, this scenario tests your understanding of how RDS Proxy decouples application connection logic from database failover events, often appearing as a trap where candidates mistakenly focus on DNS TTL adjustments or application-level retry logic instead. Remember that the proxy handles the failover transparently, so the application never sees a broken connection. Memory tip: think of RDS Proxy as a "connection concierge" that keeps your app's database sessions alive through the failover, so you don't have to wait for a new handshake.

DOP-C02 Resilient Cloud Solutions Practice Question

This DOP-C02 practice question tests your understanding of resilient cloud solutions. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.

A company runs a critical web application on Amazon EC2 instances behind an Application Load Balancer (ALB). The application uses an Amazon RDS for MySQL Multi-AZ DB instance for data storage. During an AWS infrastructure event, the primary Availability Zone (AZ) becomes unavailable, and the application experiences downtime. The RDS Multi-AZ failover completes automatically, but the application takes several minutes to reconnect. Which combination of actions would MOST reduce the recovery time for the application during such an event?

Clue words in this question

Noticing these words before you look at the options changes how you read each choice.

Clue: "primary"
Why it matters: Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.

Question 1mediummultiple choice

Read the full NAT/PAT explanation →

A
Place all EC2 instances in a single AZ and use an Amazon Route 53 health check to reroute traffic to a standby environment in another AZ.
Why wrong: Single-AZ placement is a single point of failure; Route 53 health checks cannot failover quickly enough for database connections.
B
Use an RDS proxy (Amazon RDS Proxy) to pool and share database connections, and ensure the application uses the RDS cluster endpoint.
RDS Proxy reduces connection disruption during failover by maintaining connections, and the cluster endpoint points to the current primary.
C
Deploy the RDS instance as a Single-AZ instance in the same AZ as the primary EC2 instances, and use read replicas for failover.
Why wrong: Single-AZ does not provide automatic failover; read replicas require manual promotion.
D
Configure an Application Load Balancer in front of the RDS instance to distribute connections across AZs.
Why wrong: ALB is not designed for database connections; it handles HTTP/HTTPS traffic.

Full breakdown with real-world context →

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

✓

Use an RDS proxy (Amazon RDS Proxy) to pool and share database connections, and ensure the application uses the RDS cluster endpoint.

Option B is correct because Amazon RDS Proxy maintains a warm connection pool to the database, so when the RDS Multi-AZ failover occurs, the proxy automatically reconnects to the new primary DB instance without requiring the application to re-establish connections. This eliminates the connection storm and the several-minute delay caused by the application's connection retry logic. By using the RDS cluster endpoint (which points to the proxy), the application benefits from seamless failover and reduced latency during the DNS propagation of the new primary.

Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✗
Place all EC2 instances in a single AZ and use an Amazon Route 53 health check to reroute traffic to a standby environment in another AZ.
Why it's wrong here
Single-AZ placement is a single point of failure; Route 53 health checks cannot failover quickly enough for database connections.
✓
Use an RDS proxy (Amazon RDS Proxy) to pool and share database connections, and ensure the application uses the RDS cluster endpoint.
Why this is correct
RDS Proxy reduces connection disruption during failover by maintaining connections, and the cluster endpoint points to the current primary.
Clue confirmation
The clue word "primary" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
Deploy the RDS instance as a Single-AZ instance in the same AZ as the primary EC2 instances, and use read replicas for failover.
Why it's wrong here
Single-AZ does not provide automatic failover; read replicas require manual promotion.
✗
Configure an Application Load Balancer in front of the RDS instance to distribute connections across AZs.
Why it's wrong here
ALB is not designed for database connections; it handles HTTP/HTTPS traffic.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates often assume that simply using an RDS Multi-AZ deployment is sufficient for application availability, but they overlook the critical bottleneck of application-side connection re-establishment and DNS propagation delays, which RDS Proxy directly addresses.

Detailed technical explanation

How to think about this question

RDS Proxy uses a connection multiplexing technique that keeps idle connections alive and reuses them across application requests, reducing the overhead of opening new connections during failover. Under the hood, the proxy monitors the RDS DNS endpoint and, upon detecting a failover, transparently reconnects its internal pool to the new primary, typically within 1–2 seconds. In real-world scenarios, without RDS Proxy, applications using connection pools (e.g., HikariCP) may experience a 'thundering herd' problem where hundreds of simultaneous connection attempts overwhelm the new primary, extending downtime to 5–10 minutes.

KKey Concepts to Remember

Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.

TExam Day Tips

Watch for words such as best, first, most likely and least administrative effort.
Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Real-world example

How this comes up in practice

A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.

What to study next

Got this wrong? Here's your next step.

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

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FAQ

Questions learners often ask

What does this DOP-C02 question test?

Resilient Cloud Solutions — This question tests Resilient Cloud Solutions — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: Use an RDS proxy (Amazon RDS Proxy) to pool and share database connections, and ensure the application uses the RDS cluster endpoint. — Option B is correct because Amazon RDS Proxy maintains a warm connection pool to the database, so when the RDS Multi-AZ failover occurs, the proxy automatically reconnects to the new primary DB instance without requiring the application to re-establish connections. This eliminates the connection storm and the several-minute delay caused by the application's connection retry logic. By using the RDS cluster endpoint (which points to the proxy), the application benefits from seamless failover and reduced latency during the DNS propagation of the new primary.

What should I do if I get this DOP-C02 question wrong?

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

Are there clue words in this question I should notice?

Yes — watch for: "primary". Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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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.