MLS-C01 Data Engineering Practice Question
Exhibit
Refer to the exhibit.
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": [
"s3:GetObject",
"s3:PutObject",
"s3:DeleteObject"
],
"Resource": "arn:aws:s3:::my-data-bucket/*"
},
{
"Effect": "Allow",
"Action": [
"kms:Decrypt",
"kms:GenerateDataKey"
],
"Resource": "arn:aws:kms:us-east-1:123456789012:key/abc123"
}
]
}Refer to the exhibit. A data engineer is creating an IAM policy for an AWS Glue ETL job that reads encrypted objects from an S3 bucket, transforms them, and writes the results back to the same bucket. The bucket uses SSE-KMS encryption with the KMS key specified. The ETL job is failing with an "Access Denied" error when trying to write data. What is the 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 policy is missing the kms:Encrypt permission
The IAM policy must include the kms:Encrypt permission for the AWS Glue ETL job to write encrypted objects to the S3 bucket using SSE-KMS. The policy likely includes s3:PutObject, kms:Decrypt, and kms:GenerateDataKey, but kms:Encrypt is required for the write operation. Options A, B, and C are incorrect because the necessary permissions (kms:Decrypt, s3:PutObjectAcl, and s3:PutObject) are either already present or not required for writing.
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 policy is missing the kms:Decrypt permission
Why it's wrong here
kms:Decrypt is included.
- ✗
The policy is missing the s3:PutObjectAcl permission
Why it's wrong here
ACL permissions are not required for this operation.
- ✗
The policy is missing the s3:PutObject permission
Why it's wrong here
The policy includes s3:PutObject.
- ✓
The policy is missing the kms:Encrypt permission
Why this is correct
Writing with SSE-KMS requires kms:Encrypt.
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 MLS-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 MLS-C01 exam.