DEA-C01 Data Operations and Support Practice Question
A data engineer is troubleshooting a nightly ETL job that extracts data from an Amazon RDS MySQL instance and loads it into an Amazon S3 bucket in Parquet format. The job runs on an Amazon EMR cluster and has been failing with the error 'Access Denied' when writing to S3. The IAM role attached to the EMR cluster has permissions for S3 PutObject. What is the MOST likely cause?
Answer choices
Why each option matters
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 policy denies access to the EMR cluster's IAM role.
S3 bucket policies can override IAM permissions; if the bucket policy denies access from the EMR cluster, the write will fail even with IAM allow. Option A is wrong because KMS permissions are needed only if the bucket uses SSE-KMS, which is not indicated. Option B is wrong because S3 Lifecycle rules do not affect write permissions. Option C is wrong because EMR cluster termination would cause a different error.
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 S3 bucket uses SSE-KMS encryption and the EMR role lacks kms:GenerateDataKey permission.
Why it's wrong here
This could cause an error, but typically the error message would mention KMS, not Access Denied.
- ✗
The S3 bucket has a Lifecycle rule that expires objects too quickly.
Why it's wrong here
Lifecycle rules do not deny write access.
- ✗
The EMR cluster was terminated before the write operation completed.
Why it's wrong here
Cluster termination would cause a different error.
- ✓
The S3 bucket policy denies access to the EMR cluster's IAM role.
Why this is correct
S3 bucket policies can explicitly deny access, overriding IAM allow.
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
Go deeper
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DEA-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 DEA-C01 exam.