The correct answer is a VPC endpoint for S3 and an AWS Glue connection object specifying the VPC, subnet, and security group. This configuration is required because when a Glue job runs inside a VPC, it loses its default internet access to S3, so a VPC endpoint for S3 provides a private, secure route to the S3 service without traversing the public internet, while the Glue connection object explicitly places the job’s elastic network interfaces into the correct VPC, subnet, and security group to reach the data. On the AWS Certified Machine Learning Specialty MLS-C01 exam, this question tests your understanding of how Glue interacts with network boundaries, often appearing as a scenario where you must choose between a VPC endpoint, NAT gateway, or internet gateway—the common trap is selecting a NAT gateway as required, but a VPC endpoint is the simpler, more secure default. Remember the memory tip: “Glue needs a private S3 road (VPC endpoint) and a house key (Glue connection) to enter the VPC.”
MLS-C01 Data Engineering Practice Question
This MLS-C01 practice question tests your understanding of data engineering. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Which TWO configurations are required to enable AWS Glue to access data stored in a VPC? (Choose two.)
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
A VPC endpoint for Amazon S3.
Glue jobs running inside a VPC require a VPC endpoint for S3 (or Internet/NAT) to access S3 data, and a Glue connection that specifies the VPC, subnet, and security group. Option A (VPC endpoint for S3) and Option D (Glue connection) are correct. Option B (Internet gateway) is not secure. Option C (NAT gateway) is an alternative but not required if using VPC endpoint. Option E (S3 bucket policy) is not specific to VPC access.
Key principle: Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✓
A VPC endpoint for Amazon S3.
Why this is correct
Correct: Allows Glue jobs in VPC to access S3 without Internet.
Incorrect: NATgateway is an alternative, but VPC endpoint is preferred.
✗
An Internet gateway attached to the VPC.
Why it's wrong here
Incorrect: Not required and less secure.
✗
An S3 bucket policy that allows access from the Glue service principal.
Why it's wrong here
Incorrect: Bucket policy is not directly related to VPC access.
Common exam traps
Common exam trap: usable hosts are not the same as total addresses
Subnetting questions often tempt you into counting all addresses. In normal IPv4 subnets, the network and broadcast addresses are not usable host addresses.
Detailed technical explanation
How to think about this question
Subnetting questions test whether you can identify the network, broadcast address, usable range, mask and correct subnet. Slow down enough to calculate the block size correctly.
KKey Concepts to Remember
CIDR notation defines the prefix length.
Block size helps identify subnet boundaries.
Network and broadcast addresses are not usable hosts in normal IPv4 subnets.
The required host count determines the smallest suitable subnet.
TExam Day Tips
→Write the block size before choosing the subnet.
→Check whether the question asks for hosts, subnets or a specific address range.
→Do not confuse /24, /25, /26 and /27 host counts.
Key takeaway
Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Real-world example
How this comes up in practice
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Got this wrong? Here's your next step.
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related MLS-C01 subnetting questions on CIDR, address ranges, and subnet selection.
Data Engineering — This question tests Data Engineering — CIDR notation defines the prefix length..
What is the correct answer to this question?
The correct answer is: A VPC endpoint for Amazon S3. — Glue jobs running inside a VPC require a VPC endpoint for S3 (or Internet/NAT) to access S3 data, and a Glue connection that specifies the VPC, subnet, and security group. Option A (VPC endpoint for S3) and Option D (Glue connection) are correct. Option B (Internet gateway) is not secure. Option C (NAT gateway) is an alternative but not required if using VPC endpoint. Option E (S3 bucket policy) is not specific to VPC access.
What should I do if I get this MLS-C01 question wrong?
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related MLS-C01 subnetting questions on CIDR, address ranges, and subnet selection.
What is the key concept behind this question?
CIDR notation defines the prefix length.
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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.
Question Discussion
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