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.

• ✗

  Azure Container Instances (ACI)

  Why it's wrong here

  Azure Container Instances (ACI) allows you to run a single container or a small container group in seconds without provisioning or managing VMs, which is useful for burst workloads or simple tasks. However, it does not include an orchestration layer: there is no built-in service discovery, load balancing across replicas, automatic scaling at the cluster level, or rolling update strategy. You would need to pair it with an orchestrator like Kubernetes to manage a microservices app, so ACI alone is insufficient here.

  When this WOULD be correct

  A company needs to run a single container or a simple batch job quickly without managing orchestration, and they want the fastest startup time with per-second billing. They do not require service discovery or rolling updates.

• ✓

  Azure Kubernetes Service (AKS)

  Why this is correct

  Azure Kubernetes Service (AKS) is a managed Kubernetes offering that provides full container orchestration, including automatic scaling, service discovery, rolling updates, and self-healing across a cluster of microservices. It abstracts the control plane and manages the underlying virtual machines, giving you a reliable, production-grade platform without operational overhead. This makes AKS the appropriate choice for a containerized microservices application requiring orchestration.

• ✗

  Azure App Service

  Why it's wrong here

  Azure App Service is a fully managed platform for hosting web apps, REST APIs, and mobile backends, and it can run a single containerized application via Web App for Containers. However, it is inherently a single-app PaaS: it does not offer the declarative orchestration, service-to-service discovery, pod-level scaling, or multi-service deployment model that a microservices architecture requires. Attempting to run a distributed set of microservices on App Service would force you to manage orchestration yourself, which negates the benefit.

  When this WOULD be correct

  A company wants to deploy a web application or API that runs in a container but does not require complex orchestration, service discovery, or rolling updates. They prefer a fully managed platform with built-in scaling and CI/CD support, and they want to avoid managing Kubernetes clusters.

• ✗

  Azure Functions

  Why it's wrong here

  Azure Functions is a serverless compute service designed for event-driven code snippets that execute in response to triggers, such as HTTP requests, timers, or queue messages. It automatically scales instances on demand, but each function is stateless and short-lived, lacking the control plane needed for service discovery, rolling deployments, or coordinated lifecycle management across a set of microservices. Therefore, it cannot orchestrate a long-running microservices architecture as a cohesive unit.

  When this WOULD be correct

  A company needs to run event-driven code that responds to triggers (e.g., HTTP requests, queue messages) without managing servers, and the workload is composed of small, stateless functions that scale automatically. The question would specify 'serverless compute for event-driven tasks' rather than containerized microservices.

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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