DEA-C01 Data Operations and Support Practice Question
Your company runs a data pipeline that ingests data from AWS Database Migration Service (DMS) into Amazon S3 in Parquet format. An AWS Glue ETL job then transforms the data and loads it into an Amazon Redshift cluster. The Glue job uses a JDBC connection to Redshift. Recently, the Glue job started failing with a 'communication failure' error when writing to Redshift. The Redshift cluster is in a VPC with public accessibility disabled. The Glue job runs in a VPC with a subnet that has a route to a NAT gateway. The security group for Redshift allows inbound traffic from the Glue job's security group. The Glue job's IAM role has the necessary permissions. 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 and Redshift cluster are in different VPCs that are not peered or connected via VPC Transit Gateway.
Even though the security group allows inbound traffic, the Glue job's VPC may not have a route to the Redshift cluster's VPC if they are in different VPCs. Option A is wrong because IAM permissions are not the issue. Option B is wrong because the Redshift cluster is in a VPC and not publicly accessible. Option D is wrong because the NAT gateway is for outbound internet, not for connecting to Redshift within the same VPC.
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 Glue job's IAM role does not have the redshift:DescribeClusters permission.
Why it's wrong here
The job uses a JDBC URL, not API calls; IAM permissions are for the Glue service role.
- ✗
The Redshift cluster's public accessibility is disabled, but the Glue job is trying to connect over the internet.
Why it's wrong here
The Glue job runs in a VPC and should use a private connection.
- ✓
The Glue job and Redshift cluster are in different VPCs that are not peered or connected via VPC Transit Gateway.
Why this is correct
Without VPC peering or transit gateway, the Glue job cannot reach the Redshift cluster.
- ✗
The NAT gateway is not configured to allow traffic to the Redshift cluster's subnet.
Why it's wrong here
NAT gateways are for internet traffic; Redshift is internal.
Visual reference
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.