AZ-900 Describe cloud concepts 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.

• ✗

  High Availability

  Why it's wrong here

  High Availability (HA) is concerned with maintaining service uptime and resilience in the face of infrastructure failures—such as hardware faults, network outages, or region-wide disasters—by using redundant deployments, availability zones, and fault domains. It does not, however, monitor demand metrics to change the number of running VMs; an HA architecture will keep the same instance count running but ensure those instances remain accessible, so it cannot explain a sudden increase in VM count during a peak traffic period.

  When this WOULD be correct

  A question asking about a system that remains operational despite component failures, such as deploying VMs across multiple availability zones to guarantee uptime during a data center outage.

• ✓

  Elasticity

  Why this is correct

  Elasticity is the cloud property that enables a virtual machine fleet to automatically scale out (increase the number of instances) when demand metrics such as CPU utilization or request queue length exceed a threshold, and scale in (decrease) when demand drops. This dynamic, bidirectional adjustment is typically configured through Azure Autoscale or VM Scale Sets, and it aligns resource consumption directly with real-time load, ensuring you only pay for the capacity you actually use.

• ✗

  Scalability

  Why it's wrong here

  Scalability is the general capacity of a system to handle growing workloads by adding resources, either vertically (enlarging VM sizes) or horizontally (adding more VM instances). However, scalability by itself does not imply that this scaling happens automatically in response to real-time peaks; it can be a result of manual capacity planning, pre-scheduled scaling, or long-term growth forecasting. Elasticity is specifically the automated, dynamic version of scalability that matches resources to current demand, which is what the question describes.

  When this WOULD be correct

  A question that asks: 'A company plans to add more virtual machines permanently to handle expected growth over the next year. Which cloud characteristic is this?' Here, scalability (specifically vertical or horizontal scaling) would be correct because it involves planned, long-term capacity adjustments.

• ✗

  Load Balancing

  Why it's wrong here

  Load Balancing distributes incoming network traffic across an existing pool of virtual machines to avoid overloading any single instance and to improve overall availability and responsiveness. It acts as a traffic router, using health probes and algorithms like least connections or round-robin, but it has no mechanism to provision or deprovision VMs; it only works with the set of instances that currently exist. Thus, while a load balancer may work alongside an autoscaler, it is not the component that increases the number of VMs during peak usage.

  When this WOULD be correct

  A question that asks: 'Which cloud feature distributes incoming network traffic across multiple virtual machines to ensure no single machine is overwhelmed?' would have load balancing as 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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