Question 1mediummultiple choice
Full question →mediummultiple choiceObjective-mapped
A company runs a production web application on Azure App Service. The development team is working on a new version of the application and wants to deploy it to a staging environment to perform validation tests. After testing, they need to gradually shift a percentage of live user traffic to the new version while monitoring for issues. If any problems occur, they must be able to instantly send all traffic back to the original version with zero downtime. Which Azure App Service feature should the team use to achieve this?
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
Deployment slots
Deployment slots are live environments within App Service that support staged deployment, traffic shifting via slot swapping or slot-specific routing, and instant rollback by swapping back. This feature is purpose-built for zero-downtime deployment and testing.
B
Distractor review
Azure Traffic Manager
Azure Traffic Manager is a DNS-based traffic load balancer that distributes traffic across regional endpoints. While it can route a percentage of traffic to different endpoints, it does not provide staging environments or slot swapping for App Service. It also introduces DNS propagation delays, which makes instant rollback difficult.
C
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Azure Application Gateway
Azure Application Gateway is a Layer 7 load balancer and web application firewall. It can route traffic based on URL paths or other criteria, but it does not offer staging environments or the ability to swap application versions with zero downtime. Managing version rollback would require manual reconfiguration.
D
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Azure Front Door
Azure Front Door is a global HTTP(S) load balancer with traffic acceleration and traffic splitting capabilities. It can shift a percentage of traffic to different backends, but it does not provide the staging environments or the simple swap mechanism that deployment slots offer. It also requires external management of backend swapping.
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: Deployment slots — Azure App Service deployment slots are separate environments within an App Service plan that allow you to deploy different versions of an application. You can perform staging and testing in a slot (e.g., 'staging') and then swap it with the production slot, optionally using auto-swap or slot-specific traffic routing to gradually shift traffic. Swapping keeps the same hostnames and settings, and it enables instant rollback by swapping back. Traffic Manager is a DNS-based global traffic router and does not integrate directly with App Service slots. Application Gateway is a Layer 7 load balancer but does not provide staging environments or slot swapping. Azure Front Door is a global HTTP(S) load balancer with traffic splitting, but deployment slots are the native App Service feature designed for this exact scenario, offering simpler management and zero-downtime deployment.
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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