The answer is that the S3 bucket name in the IAM policy does not match the actual bucket the Lambda function is trying to write to. This is the most common cause of a lambda function cannot write to s3 bucket access denied error, because the policy explicitly grants s3:PutObject on the resource ARN `arn:aws:s3:::my-bucket/*`, but if the function’s code references a different bucket name—say, `production-bucket`—the permission simply does not apply, and AWS denies the write. On the AWS Certified Data Engineer Associate DEA-C01 exam, this scenario tests your ability to read IAM policy resource ARNs carefully and match them against the actual S3 bucket used in the function’s runtime logic. A common trap is assuming the policy is too restrictive on actions when the real issue is a simple naming mismatch. Remember the mnemonic: “Policy path must match the bucket path, or you’ll get a denied aftermath.”
DEA-C01 Data Ingestion and Transformation Practice Question
This DEA-C01 practice question tests your understanding of data ingestion and transformation. 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.
Refer to the exhibit. A Lambda function with this IAM policy is used to process records from a Kinesis stream and write to S3. The function is failing with access denied errors when writing to S3. What is the issue?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The S3 bucket name in the policy does not match the actual bucket used by the function.
Option B is correct because the policy allows s3:PutObject on 'my-bucket/*' but the function might be writing to a different bucket or the resource ARN is missing permissions for the bucket itself (e.g., s3:ListBucket). Option A is wrong because the policy includes GetRecords. Option C is wrong because the policy has kinesis actions. Option D is wrong because Kinesis Data Analytics is not mentioned.
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.
✗
The function needs to use Kinesis Data Analytics for transformation.
Why it's wrong here
Not related to permissions.
✗
The Kinesis stream ARN is incorrect.
Why it's wrong here
Would cause errors on stream side, not S3.
✗
The Lambda function does not have permission to read from the Kinesis stream.
Why it's wrong here
It has GetRecords, GetShardIterator, DescribeStream.
✓
The S3 bucket name in the policy does not match the actual bucket used by the function.
Why this is correct
Common cause of access denied.
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 DEA-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.
Data Ingestion and Transformation — This question tests Data Ingestion and Transformation — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The S3 bucket name in the policy does not match the actual bucket used by the function. — Option B is correct because the policy allows s3:PutObject on 'my-bucket/*' but the function might be writing to a different bucket or the resource ARN is missing permissions for the bucket itself (e.g., s3:ListBucket). Option A is wrong because the policy includes GetRecords. Option C is wrong because the policy has kinesis actions. Option D is wrong because Kinesis Data Analytics is not mentioned.
What should I do if I get this DEA-C01 question wrong?
Identify which DEA-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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