DBS-C01 Deployment and Migration Practice Question
This DBS-C01 practice question tests your understanding of deployment and migration. 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.
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?
Network Topology
A
Change the cluster's endpoint to point to instance-2.
Why wrong: Cluster endpoints are managed by RDS; you cannot manually redirect them.
B
Modify 'mycluster-instance-2' to promote it to writer.
Why wrong: There is no modify action to promote an instance; failover is required.
C
Reboot 'mycluster-instance-1' to trigger a failover.
Why wrong: Rebooting the writer causes a failover but does not guarantee instance-2 becomes the writer.
D
Use the AWS CLI: aws rds failover-db-cluster --db-cluster-identifier mycluster --target-db-instance-identifier mycluster-instance-2
This command initiates failover to the specified instance.
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
The AWS CLI command `aws rds failover-db-cluster` with the `--target-db-instance-identifier` parameter allows you to explicitly specify which Aurora replica should become the new writer instance. This is the most direct and supported method to initiate a controlled failover to 'mycluster-instance-2' without rebooting the current writer or manually modifying endpoints.
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
The trap here is that candidates confuse rebooting an instance with triggering a failover, or assume that modifying an instance's settings can promote it, when in fact only the cluster-level failover command can explicitly designate a target replica as the new writer.
Detailed technical explanation
How to think about this question
Under the hood, Aurora uses a shared storage volume and a quorum-based replication model. The `failover-db-cluster` command sends a request to the cluster's consensus protocol to demote the current writer and promote the target replica, updating the cluster endpoint DNS record within seconds. In a real-world scenario, this is critical for zero-downtime maintenance because you can failover to a specific replica that has been pre-warmed with connections or is in a different Availability Zone.
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 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 exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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 — The AWS CLI command `aws rds failover-db-cluster` with the `--target-db-instance-identifier` parameter allows you to explicitly specify which Aurora replica should become the new writer instance. This is the most direct and supported method to initiate a controlled failover to 'mycluster-instance-2' without rebooting the current writer or manually modifying endpoints.
What should I do if I get this DBS-C01 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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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