Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
You are developing an Azure Function that processes messages from an Azure Service Bus queue. The function uses a Service Bus queue trigger and runs on a Consumption Plan. The queue receives a high volume of messages in bursts. You need to ensure that the function scales out to handle the load but does not exceed 10 concurrent instances. Which configuration should you apply?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
Set the 'maxConcurrentCalls' property to 10 in the host.json file.
maxConcurrentCalls limits the number of messages processed concurrently per instance, not the number of instances. Setting it to 10 would not cap total instances.
B
Best answer
Set the 'WEBSITE_MAX_INSTANCES' application setting to 10 in the function app.
Correct. The WEBSITE_MAX_INSTANCES setting limits the maximum number of instances that the function app can scale out to. This is the correct way to cap the number of concurrent instances.
C
Distractor review
Set the 'maxMessageBatchSize' property to 10 in the host.json file.
maxMessageBatchSize specifies the maximum number of messages retrieved per batch per instance. It does not limit the number of instances.
D
Distractor review
Restrict the Service Bus queue to have a maximum concurrency of 10 at the namespace level.
Service Bus queues do not have a setting to limit concurrency per consumer at the namespace level. The scaling is controlled by the consumer (the function app).
Common exam trap
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Technical deep dive
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
- Use explanations to understand the rule behind the answer.
TExam Day Tips
- Underline the problem statement mentally.
- 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.
Related practice questions
Related AZ-204 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
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FAQ
Questions learners often ask
What does this AZ-204 question test?
Read the scenario before looking for a memorised answer.
What is the correct answer to this question?
The correct answer is: Set the 'WEBSITE_MAX_INSTANCES' application setting to 10 in the function app. — Azure Functions with Service Bus triggers have configuration options for scaling. The key property is 'maxConcurrentCalls' which controls how many messages are processed concurrently per instance. However, to limit the number of function app instances, you can set the 'WEBSITE_MAX_INSTANCES' app setting. For Service Bus triggers, you can also set 'maxMessageBatchSize' but that relates to batch processing per instance, not instance count.
What should I do if I get this AZ-204 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
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