The answer is to use the AWS CLI command `aws rds failover-db-cluster --db-cluster-identifier mycluster --target-db-instance-identifier mycluster-instance-2`. This is correct because the `--target-db-instance-identifier` parameter lets you specify exactly which reader instance should become the new writer, giving you precise control over the failover target rather than leaving it to Amazon’s automatic selection. On the AWS Certified Database Specialty DBS-C01 exam, this question tests your understanding of Aurora’s failover mechanics and the distinction between a forced failover and a simple reboot—the common trap is assuming that rebooting the writer will always promote a specific reader, but without the target parameter, Aurora may choose any healthy replica. Remember the key: to failover to a specific reader DB instance, you must explicitly name it in the failover command. Memory tip: “Target the reader, or the cluster chooses the leader.”
DBS-C01 Deployment and Migration Practice Question
This DBS-C01 practice question tests your understanding of deployment and migration. 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.
Network Topology
A company has an Aurora MySQL cluster with three instances. The current writer instance is 'mycluster-instance-1'. The company wants to failover to 'mycluster-instance-2' for maintenance. What is the most direct way to achieve this?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use the AWS CLI: aws rds failover-db-cluster --db-cluster-identifier mycluster --target-db-instance-identifier mycluster-instance-2
Option B is correct because you can failover to a specific reader instance by using the --target-db-instance-identifier parameter in the failover-db-cluster command. Option A is wrong because rebooting the writer will cause a failover but may choose any reader, not necessarily instance-2. Option C is wrong because you cannot directly promote a reader to writer; failover must be initiated. Option D is wrong because modifying the cluster does not trigger failover.
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.
✗
Change the cluster's endpoint to point to instance-2.
Why it's wrong here
Cluster endpoints are managed by RDS; you cannot manually redirect them.
✗
Modify 'mycluster-instance-2' to promote it to writer.
Why it's wrong here
There is no modify action to promote an instance; failover is required.
✗
Reboot 'mycluster-instance-1' to trigger a failover.
Why it's wrong here
Rebooting the writer causes a failover but does not guarantee instance-2 becomes the writer.
✓
Use the AWS CLI: aws rds failover-db-cluster --db-cluster-identifier mycluster --target-db-instance-identifier mycluster-instance-2
Why this is correct
This command initiates failover to the specified instance.
Related concept
Read the scenario before looking for a memorised answer.
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 cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Got this wrong? Here's your next step.
Identify which DBS-C01 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.
Deployment and Migration — This question tests Deployment and Migration — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Use the AWS CLI: aws rds failover-db-cluster --db-cluster-identifier mycluster --target-db-instance-identifier mycluster-instance-2 — Option B is correct because you can failover to a specific reader instance by using the --target-db-instance-identifier parameter in the failover-db-cluster command. Option A is wrong because rebooting the writer will cause a failover but may choose any reader, not necessarily instance-2. Option C is wrong because you cannot directly promote a reader to writer; failover must be initiated. Option D is wrong because modifying the cluster does not trigger failover.
What should I do if I get this DBS-C01 question wrong?
Identify which DBS-C01 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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Question Discussion
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