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.

• ✗

  Deploy the VMs in an availability set.

  Why it's wrong here

  An availability set distributes VMs across different fault domains and update domains within a single datacenter. While it protects against hardware failures and planned maintenance within that datacenter, it does not protect against the failure of the entire datacenter itself.

  When this WOULD be correct

  If the question asked for protection against hardware failures within a single datacenter (e.g., server or rack failure) and the solution must be within one region, deploying VMs in an availability set would be correct.

• ✗

  Deploy the VMs in different Azure regions connected with Azure Traffic Manager.

  Why it's wrong here

  Using different Azure regions with Azure Traffic Manager is a disaster recovery or multi-region deployment strategy, not a single-region high-availability solution. The requirement explicitly limits the deployment to the East US region, so placing VMs in another region (e.g., West US) violates that constraint. While Traffic Manager can route user traffic to healthy endpoints across regions, it cannot make the application reside solely in East US. Therefore, this option is incorrect for the stated scope.

  When this WOULD be correct

  If the question required the highest availability across multiple regions (e.g., 'The application must remain available if an entire Azure region fails'), deploying VMs in different regions with Traffic Manager would be correct.

• ✓

  Deploy the VMs in different availability zones within East US.

  Why this is correct

  Availability zones are physically separate locations within the East US region, each with independent power, cooling, and networking infrastructure. Deploying the mission-critical VMs across different zones ensures that a datacenter-wide failure in one zone does not take the application down, because traffic automatically shifts to the surviving zone. This meets the requirement for a single-region deployment while providing the required fault isolation. Availability zones therefore give a higher uptime SLA than other single-region options.

• ✗

  Deploy all VMs in the same availability set but in different fault domains.

  Why it's wrong here

  An availability set with VMs spread across different fault domains only protects against hardware failures within a single datacenter. Fault domains share the same physical power and networking infrastructure within that datacenter, so they cannot survive a complete datacenter outage. Since the company needs the application to remain available even if an entire datacenter fails, this configuration is insufficient. It provides rack-level resilience but not the requested datacenter-level isolation.

  When this WOULD be correct

  If the question asked for high availability within a single datacenter (e.g., to protect against hardware failures like server or rack failures) and the region does not support availability zones, then deploying VMs in an availability set with multiple fault domains would be the correct answer.

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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