AZ-400 Implement an instrumentation strategy Practice Question
This AZ-400 practice question tests your understanding of implement an instrumentation strategy. 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.
A company deploys a web application to Azure App Service. They want to monitor application performance and detect anomalies using Application Insights. Which two components should be configured?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Configure sampling to reduce data volume
Option B is correct because sampling in Application Insights reduces the volume of telemetry data while preserving statistically correct analysis, which is essential for managing cost and performance in high-traffic applications. Option D is correct because the application-side SDK (e.g., Application Insights SDK for .NET, Java, or Node.js) is required to instrument the code and collect detailed telemetry such as requests, dependencies, and exceptions for performance monitoring and anomaly detection.
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 Azure Monitor agent on the App Service instance
Why it's wrong here
Azure Monitor agent is for VMs, not App Service.
✓
Configure sampling to reduce data volume
Why this is correct
Sampling preserves representative data and reduces cost while still enabling anomaly detection.
Related concept
Read the scenario before looking for a memorised answer.
✗
Create a Log Analytics workspace and configure data collection rules
Why it's wrong here
Log Analytics stores data but does not directly detect anomalies.
✓
Enable application-side SDK for telemetry
Why this is correct
SDK collects detailed performance and usage data needed for anomaly detection.
Related concept
Read the scenario before looking for a memorised answer.
✗
Enable diagnostics settings to stream logs to Event Hubs
Why it's wrong here
Streams platform logs, not application telemetry for performance anomalies.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse the Azure Monitor agent (for VMs) with the App Service diagnostics settings or Log Analytics workspaces, thinking they are required for Application Insights instrumentation, when in fact the SDK and sampling are the two core components for application performance monitoring and anomaly detection.
Detailed technical explanation
How to think about this question
Application Insights sampling can be adaptive (automatically adjusting based on telemetry volume) or fixed-rate; it uses a hashing algorithm on the operation ID to ensure that all telemetry for a given request is either fully sampled or fully dropped, preserving transaction integrity. The SDK collects telemetry via the standard OpenTelemetry protocol or the older Application Insights protocol, and it automatically correlates telemetry using operation IDs and parent-child relationships, enabling end-to-end transaction diagnostics. In a real-world scenario, without sampling, a high-traffic e-commerce site could generate terabytes of telemetry daily, making storage costs prohibitive and query performance slow, while sampling reduces volume by 90% or more with minimal statistical impact on anomaly detection.
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 startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this AZ-400 question in full detail.
Implement an instrumentation strategy — This question tests Implement an instrumentation strategy — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Configure sampling to reduce data volume — Option B is correct because sampling in Application Insights reduces the volume of telemetry data while preserving statistically correct analysis, which is essential for managing cost and performance in high-traffic applications. Option D is correct because the application-side SDK (e.g., Application Insights SDK for .NET, Java, or Node.js) is required to instrument the code and collect detailed telemetry such as requests, dependencies, and exceptions for performance monitoring and anomaly detection.
What should I do if I get this AZ-400 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.
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Question Discussion
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