The answer is to enable ElastiCache for Redis cluster mode with automatic failover across multiple Availability Zones. This configuration ensures high availability by automatically promoting a read replica in a different AZ to primary if the original primary node fails, making the session data resilient to both node and AZ outages. On the AWS Certified DevOps Engineer Professional DOP-C02 exam, this question tests your understanding that cluster mode with Multi-AZ provides automatic failover for sharded Redis deployments, whereas standard Multi-AZ applies only to replication groups without sharding. A common trap is confusing standard Multi-AZ (which lacks automatic failover for cluster mode) with cluster mode Multi-AZ, or thinking manual promotion or S3 backups suffice for real-time HA. Remember the key distinction: cluster mode + Multi-AZ equals automatic failover; without cluster mode, you get only manual replica promotion. Memory tip: “Cluster + Multi-AZ = Auto-Failover, no cluster = manual only.”
DOP-C02 Resilient Cloud Solutions Practice Question
This DOP-C02 practice question tests your understanding of resilient cloud solutions. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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 is running a stateful web application on Amazon EC2 instances. The application stores session data locally on the instance. The company wants to make the application stateless and improve resilience. The DevOps team decides to use Amazon ElastiCache for Redis to store session data. What additional step should the team take to ensure that the session data is highly available?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Enable ElastiCache for Redis cluster mode with automatic failover across multiple Availability Zones.
Option B is correct. Enabling ElastiCache for Redis cluster mode with automatic failover ensures that if the primary node fails, a read replica is promoted, providing high availability. Option A is wrong because Multi-AZ for ElastiCache is for replication groups, not cluster mode. Option C is wrong because backing up to S3 does not provide automatic failover. Option D is wrong because manually promoting a replica is not automatic.
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.
✗
Deploy ElastiCache for Redis in a Multi-AZ configuration with automatic failover.
Why it's wrong here
Multi-AZ is for replication groups, but cluster mode provides better scalability and HA.
✗
Use a single ElastiCache for Redis node and rely on the application to reconnect if the node fails.
Why it's wrong here
No automatic failover.
✓
Enable ElastiCache for Redis cluster mode with automatic failover across multiple Availability Zones.
Why this is correct
Cluster mode with automatic failover ensures HA.
Related concept
Read the scenario before looking for a memorised answer.
✗
Configure ElastiCache for Redis to back up session data to Amazon S3 every 5 minutes.
Why it's wrong here
Backups do not provide automatic failover.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→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 DOP-C02 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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: Enable ElastiCache for Redis cluster mode with automatic failover across multiple Availability Zones. — Option B is correct. Enabling ElastiCache for Redis cluster mode with automatic failover ensures that if the primary node fails, a read replica is promoted, providing high availability. Option A is wrong because Multi-AZ for ElastiCache is for replication groups, not cluster mode. Option C is wrong because backing up to S3 does not provide automatic failover. Option D is wrong because manually promoting a replica is not automatic.
What should I do if I get this DOP-C02 question wrong?
Identify which DOP-C02 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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.
Question Discussion
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