DEA-C01 Data Ingestion and Transformation Practice Question
A company is using AWS Glue to run ETL jobs that process data from Amazon S3 and load it into Amazon Redshift. The jobs are failing with the error 'Unable to connect to Redshift cluster'. The Redshift cluster is in the same VPC as the Glue job. 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 Glue job is not configured to use the same VPC as the Redshift cluster.
The most likely cause is that the Glue job is not configured to use the same VPC as the Redshift cluster. By default, AWS Glue jobs run in a separate VPC managed by Glue. To connect to resources in a customer VPC (like a Redshift cluster), the Glue job must be explicitly associated with that VPC via a Glue connection or job configuration. Option C is correct. Option A is incorrect because even if the security group allows inbound traffic, the Glue job's network may not be routed to the Redshift cluster if it is in a different VPC. Option B is incorrect because the IAM role handles authentication, not network connectivity. Option D is incorrect because the Redshift cluster is in the same VPC, so public accessibility is not required; the error indicates a network connectivity issue, not a public access issue.
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 Redshift cluster's security group does not allow inbound traffic from the Glue job's security group.
Why it's wrong here
While this could be an issue, the most likely cause is that the Glue job is not in the VPC at all.
- ✗
The IAM role associated with the Glue job does not have permission to access Redshift.
Why it's wrong here
IAM permissions are necessary but the error message suggests a network connectivity issue.
- ✓
The Glue job is not configured to use the same VPC as the Redshift cluster.
Why this is correct
Glue jobs need VPC configuration to access resources in a private VPC.
- ✗
The Redshift cluster is not publicly accessible and Glue is trying to connect from outside the VPC.
Why it's wrong here
If the Glue job is not in the VPC, this is a symptom, not the root cause.
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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JA
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.