The answer is ec2:CreateInstance, or an equivalent EC2 permission, because AWS DMS replication instances are actually EC2 instances under the hood, so the IAM policy must explicitly grant the ability to launch them. Without this permission, the migration engineer can create DMS tasks and endpoints but will fail when attempting to provision the replication instance itself. On the AWS Certified Database Specialty DBS-C01 exam, this tests your understanding that DMS relies on underlying EC2 compute resources, and a common trap is assuming that DMS-specific actions like dms:CreateReplicationInstance are sufficient—they are not, as the service calls EC2 APIs on your behalf. A helpful memory tip is to think “DMS runs on EC2, so to create a DMS instance, you must first be allowed to create an EC2 instance.”
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.
Refer to the exhibit. A company is creating an IAM policy for a migration engineer who needs to perform a database migration from an on-premises SQL Server to Amazon RDS for SQL Server using AWS DMS. The policy is attached to the engineer's IAM user. Which additional permission is required for the engineer to create a DMS replication instance?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
ec2:CreateInstance (or equivalent)
Option A is correct because to create a DMS replication instance, the IAM user needs permissions to create EC2 instances, as replication instances run on EC2. The policy currently allows creating DMS tasks but not the replication instance itself. Option B is wrong because DMS endpoints do not require EC2 permissions. Option C is wrong because S3 permissions are not needed for the replication instance. Option D is wrong because KMS permissions are for encryption keys, not for creating the replication instance.
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.
✗
kms:CreateKey
Why it's wrong here
KMS permissions are optional for encryption, not required for creating the instance.
✗
dms:CreateEndpoint
Why it's wrong here
Creating endpoints does not require EC2 permissions.
✗
s3:PutObject
Why it's wrong here
S3 permissions are not needed for creating a replication instance.
✓
ec2:CreateInstance (or equivalent)
Why this is correct
DMS replication instances require EC2 permissions to be created.
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 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 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: ec2:CreateInstance (or equivalent) — Option A is correct because to create a DMS replication instance, the IAM user needs permissions to create EC2 instances, as replication instances run on EC2. The policy currently allows creating DMS tasks but not the replication instance itself. Option B is wrong because DMS endpoints do not require EC2 permissions. Option C is wrong because S3 permissions are not needed for the replication instance. Option D is wrong because KMS permissions are for encryption keys, not for creating the replication instance.
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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This DBS-C01 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 DBS-C01 exam.
Question Discussion
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