DEA-C01 Data Operations and Support Practice Question
A data engineer runs a Spark job on Amazon EMR that reads data from Amazon S3 and writes results back to S3. The job fails with an 'S3AccessDenied' error. The engineer verifies that the IAM role attached to the EMR cluster has s3:GetObject and s3:PutObject permissions on the relevant buckets. What is the MOST likely cause of the error?
⚠ Common exam trap
It's easy for candidates to assume GetObject and PutObject are sufficient for S3 read/write operations, overlooking that the ListBucket permission is required for directory listing and file discovery in Spark jobs.
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 IAM role does not have s3:ListBucket permission on the bucket.
The IAM role attached to the EMR cluster must have the s3:ListBucket permission on the bucket to allow the Spark job to enumerate objects when reading from S3. Without this permission, even with s3:GetObject and s3:PutObject, the job fails with an 'S3AccessDenied' error because the S3 list operation is required for directory listing and file discovery.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
S3 Transfer Acceleration is not enabled on the bucket.
Why it's wrong here
Transfer Acceleration speeds up cross-region uploads over AWS edge locations; it does not grant permissions, so it cannot resolve an S3AccessDenied error caused by policy or encryption restrictions. It is tempting because it addresses S3 access performance, and would be correct when large uploads from distant clients need faster throughput.
- ✗
EMRFS consistent view is not configured.
Why it's wrong here
EMRFS consistent view tracks S3 object listings to avoid stale metadata during EMR jobs; it does not authorise object reads or writes, so it cannot cause or fix an S3AccessDenied error. It is tempting because it is an EMRFS-specific S3 setting, and would be correct when jobs need consistent listings after objects are added or removed.
- ✗
The S3 bucket is in a different AWS Region than the EMR cluster.
Why it's wrong here
Cross-region S3 access is permitted by IAM policies and incurs latency and data-transfer charges, but does not produce S3AccessDenied; the error indicates an authorisation or policy denial instead. It is tempting because region mismatches cause connectivity issues, and would be correct if the failure were latency or endpoint-related rather than an access denial.
- ✓
The IAM role does not have s3:ListBucket permission on the bucket.
Why this is correct
Spark's S3A filesystem lists the bucket or prefix before reading and writing objects, and that listing call requires s3:ListBucket on the bucket resource. GetObject and PutObject alone are insufficient, so the missing ListBucket permission causes the S3AccessDenied failure.
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.