Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
A company is building a mobile app backend that handles HTTP requests from thousands of users. The traffic pattern is highly unpredictable: there can be sudden spikes to hundreds of requests per second followed by long periods of no activity. The development team wants a solution that automatically scales from zero to hundreds of instances based on demand, and they want to pay only for the compute time consumed when the code is actually executing. They do not want to manage any underlying infrastructure, such as virtual machines or containers. Which Azure compute service should they choose?
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
Best answer
Azure Functions
Correct. Azure Functions is a serverless compute service that automatically scales based on demand and charges only for execution time. It can scale to zero when idle, exactly matching the requirements.
B
Distractor review
Azure App Service
Incorrect. Azure App Service can autoscale, but in most plans it requires at least one instance running continuously (always-on). It does not scale to zero and you incur charges even when no requests are processed.
C
Distractor review
Azure Kubernetes Service (AKS)
Incorrect. AKS is a container orchestration service that runs on virtual machines. You are responsible for managing the node pool (VMs) and paying for the underlying compute resources even when no containers are running. It does not scale to zero and is not a serverless solution in its standard form.
D
Distractor review
Azure Virtual Machines
Incorrect. Azure Virtual Machines require you to manage the operating system and scaling configuration. Even if you use VM scale sets with autoscale, the VMs remain allocated and incur costs even when idle. Scaling to zero is not possible without manually deallocating all VMs.
Common exam trap
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Technical deep dive
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
- Static NAT maps one inside address to one outside address.
- PAT allows many inside hosts to share one public address using ports.
- Inside local and inside global describe the private and translated addresses.
- NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
- Identify inside and outside interfaces first.
- Check whether the scenario needs static NAT, dynamic NAT or PAT.
- Do not confuse NAT matching ACLs with normal packet-filtering intent.
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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.
Question 1
A developer is building a serverless application that requires integration with an on-premises SQL Server database for real-time data processing. The on-premises network is connected to Azure via a site-to-site VPN. Which Azure service would allow the function to securely access the on-premises database without exposing it to the public internet?
Question 2
A solutions architect is designing a storage solution for a large media company. The company needs to store video files that are accessed infrequently but must be retained for several years for compliance. Which two Azure storage options meet these requirements? (Select two.)
Question 3
A company deploys a multi-tier application using Azure virtual machines. The web tier VMs must be evenly distributed across two distinct data centers within an Azure region to avoid a single point of failure from an infrastructure outage. Which Azure construct should they use to meet this requirement?
Question 4
A company wants to enforce a set of security policies across all their Azure subscriptions. They have created several individual policy definitions. Which Azure construct should they use to group these policies together and assign them as a single package?
Question 5
A company deploys a line-of-business application on an Azure virtual machine. The IT team wants to ensure the application remains secure. According to the shared responsibility model, which of the following security tasks is the sole responsibility of the customer (the company)?
Question 6
A company develops a web API that runs on Azure App Service. The development team wants to deploy a new version of the API to a staging environment, run integration tests against it, and then gradually shift production traffic to the new version. If any issues are detected, they want to immediately roll back to the previous version without redeploying. Which Azure App Service feature should the team use to meet these requirements?
FAQ
Questions learners often ask
What does this AZ-900 question test?
Static NAT maps one inside address to one outside address.
What is the correct answer to this question?
The correct answer is: Azure Functions — Azure Functions is a serverless compute service that runs your code on-demand, automatically scaling from zero to thousands of instances. You pay only for the compute time when your function runs, making it ideal for unpredictable, event-driven workloads. Azure App Service can scale but does not support scaling to zero (it requires at least one always-on instance). Azure Kubernetes Service (AKS) requires managing a cluster of nodes (virtual machines) and is not truly serverless. Azure Virtual Machines require full management of the OS and scaling is manual or via scale sets with VMs that run continuously.
What should I do if I get this AZ-900 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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