AZ-900 Describe Azure architecture and services Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✗

  A) Azure Virtual Machines

  Why it's wrong here

  With Azure Virtual Machines, you are responsible for provisioning, patching, securing, and maintaining the operating system, the container runtime, and any orchestration tooling that runs on top of it. There is no platform-level abstraction: you must handle VM health, scaling, and failover logic yourself. Thus, using VMs to run a containerized application means fully managing the infrastructure, which directly contradicts the goal of running the app without managing the underlying servers.

  When this WOULD be correct

  If the question asked for a service to run a custom application with full control over the OS and software stack, and managing VMs is acceptable, then Azure Virtual Machines would be correct.

• ✓

  B) Azure Kubernetes Service (AKS)

  Why this is correct

  Azure Kubernetes Service (AKS) is a managed Kubernetes offering in which Azure operates the control plane—the API server, etcd, and scheduler—while providing automated upgrades, health monitoring, and scaling. You still configure a node pool of VMs, but the raw virtual machines are pooled into a managed cluster rather than existing as standalone infrastructure you provision and track individually. For running containerized applications, AKS gives you native orchestration with pods, auto-scaling, load balancing, and rolling deployments, making it the appropriate abstraction when you want to avoid managing the Kubernetes control plane yourself.

• ✗

  C) Azure App Service

  Why it's wrong here

  Azure App Service is a platform-as-a-service (PaaS) designed for web apps, REST APIs, and background jobs. It can deploy container images using App Service for Containers, but it hosts each app in a single web sandbox or a group of containers defined with Docker Compose; it does not expose Kubernetes-native constructs such as pods, services, replica sets, or horizontal pod autoscaling. If you choose App Service to run a containerized application, you are adopting a web hosting platform, not a generalized container orchestrator, and you lose the orchestration capabilities that AKS provides.

  When this WOULD be correct

  A company wants to host a web application built with ASP.NET or Node.js without managing the underlying infrastructure, and they do not require container orchestration or multi-container management. In that case, Azure App Service would be the correct answer.

• ✗

  D) Azure Functions

  Why it's wrong here

  Azure Functions is a serverless compute service built around event-driven triggers—HTTP, timers, queues, and blob events—and it executes code inside an isolated managed runtime rather than letting you run an arbitrary container image. Although Functions supports custom handlers and can run containers under certain models, it is not a container-runtime service for general applications; you would have to re-architect your containerized workload as a function to fit the trigger model. For an existing containerized application, Functions would require decomposition into discrete, event-driven functions rather than simply hosting the container.

  When this WOULD be correct

  A company wants to run event-driven code that responds to triggers (e.g., HTTP requests, queue messages) without managing servers. They should use Azure Functions when the workload is stateless, short-lived, and does not require full container orchestration.

Option-by-option analysis

Why each answer is right or wrong

Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The AZ-900 exam frequently reuses these exact scenarios with slightly different constraints.

Analysis generated from the official AZ-900blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”

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