- A
Deploy the challenger model (v2) to the same endpoint as the champion (v1).
Both models must be on the same endpoint to use traffic splitting.
- B
Modify your application to log which model version served each prediction.
You need to correlate predictions with the model version to measure business metrics per version.
- C
Create a new endpoint for v2 and gradually shift DNS traffic.
Why wrong: This does not use Vertex AI's built-in A/B testing capability and is more complex.
- D
Use Vertex AI Experiments to compare model performance.
Why wrong: Experiments are for training, not serving A/B tests.
- E
Set up a traffic split between v1 and v2, e.g., 90% v1 and 10% v2.
Traffic splitting enables A/B testing by routing a percentage of requests to each version.
Question 492 of 1,000
PMLE Serving and Scaling Models Practice Question
This PMLE practice question tests your understanding of serving and scaling models. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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.
Your team has deployed a model on Vertex AI endpoints and you are planning an A/B test to compare a new challenger model (v2) against the current champion (v1). The test should measure business metrics such as click-through rate. Which THREE steps should you take to set up the A/B test correctly? (Choose 3 correct answers)
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
✓
Deploy the challenger model (v2) to the same endpoint as the champion (v1).
Option A is correct because deploying both v1 and v2 to the same Vertex AI endpoint allows you to use the built-in traffic splitting feature. This enables you to route a percentage of requests to each model version without managing separate endpoints or DNS changes, which is the standard approach for A/B testing on Vertex AI.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Deploy the challenger model (v2) to the same endpoint as the champion (v1).
Why this is correct
Both models must be on the same endpoint to use traffic splitting.
Related concept
Read the scenario before looking for a memorised answer.
- ✓
Modify your application to log which model version served each prediction.
Why this is correct
You need to correlate predictions with the model version to measure business metrics per version.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Create a new endpoint for v2 and gradually shift DNS traffic.
Why it's wrong here
This does not use Vertex AI's built-in A/B testing capability and is more complex.
- ✗
Use Vertex AI Experiments to compare model performance.
Why it's wrong here
Experiments are for training, not serving A/B tests.
- ✓
Set up a traffic split between v1 and v2, e.g., 90% v1 and 10% v2.
Why this is correct
Traffic splitting enables A/B testing by routing a percentage of requests to each version.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates confuse Vertex AI Experiments (for training) with endpoint traffic splitting (for serving), and they incorrectly think creating separate endpoints with DNS shifting is a valid A/B testing method, when Vertex AI's native traffic splitting is the correct and simpler approach.
Detailed technical explanation
How to think about this question
Vertex AI endpoints support traffic splitting by assigning a percentage of requests to each model version deployed on the same endpoint. This is implemented at the load balancer level, where the endpoint's routing algorithm distributes incoming requests based on the configured split (e.g., 90% to v1, 10% to v2). Logging the model version (option B) is critical because the prediction response does not automatically include which version served it; you must add a custom header or log entry in your application to correlate business metrics with the model version.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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FAQ
Questions learners often ask
What does this PMLE question test?
Serving and Scaling Models — This question tests Serving and Scaling Models — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Deploy the challenger model (v2) to the same endpoint as the champion (v1). — Option A is correct because deploying both v1 and v2 to the same Vertex AI endpoint allows you to use the built-in traffic splitting feature. This enables you to route a percentage of requests to each model version without managing separate endpoints or DNS changes, which is the standard approach for A/B testing on Vertex AI.
What should I do if I get this PMLE question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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Last reviewed: Jul 4, 2026
This PMLE practice question is part of Courseiva's free Google Cloud 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 PMLE exam.
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