AZ-900 Describe cloud concepts Practice Question
A company runs a nightly data processing job that requires high CPU usage for only 15 minutes. During the day, the compute resources are idle. The company wants to reduce costs by automatically starting compute resources only when the job runs and shutting them down after completion, without manual intervention. Which cloud computing characteristic directly meets this requirement?
⚠ Common exam trap
Candidates often confuse scalability (ability to handle growth, often manual or planned) with elasticity (automatic, real-time scaling to match demand), leading them to pick scalability even though the requirement explicitly calls for automatic start/stop without intervention.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Elasticity
Elasticity is the cloud computing characteristic that enables resources to be automatically provisioned and de-provisioned in response to workload demands. In this scenario, the nightly job requires high CPU for only 15 minutes, and elasticity allows the compute resources to scale up exactly when the job starts and scale down to zero after completion, eliminating idle costs without manual intervention.
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 is concerned with maximizing uptime by distributing a service across redundant zones or regions so that a failure does not cause prolonged downtime. It typically involves running multiple identical instances continuously, which actually increases long-term resource usage and cost rather than reducing it. Achieving high availability does not automatically stop idle resources after a nightly job, so it does not align with the described cost-saving requirement.
When this WOULD be correct
A question asks: 'A company needs to ensure its application remains accessible despite a regional outage. Which characteristic should they prioritize?' In that context, high availability would be correct.
- ✓
Elasticity
Why this is correct
Elasticity is the cloud property that lets a system automatically provision and release compute resources to match real-time workload demand. For a nightly data processing job, resources can be spun up at the scheduled start time and deprovisioned when the job finishes, so the business pays only for the active processing window. This dynamic start/stop behavior directly lowers cost, which is exactly what this scenario requires.
- ✗
Fault tolerance
Why it's wrong here
Fault tolerance is a design property that keeps a workload operational even when one or more components—such as VMs, network links, or storage—fail. It relies on redundant components and automatic failover to eliminate a single point of failure, but it does not schedule resource startup or shutdown based on job timing or demand. A nightly batch job that simply runs and stops does not inherently need fault tolerance to meet its cost-saving goal.
- ✗
Scalability
Why it's wrong here
Scalability is the capacity to add more resources, either vertically (increasing power of a single instance) or horizontally (adding more instances) to handle increased load. While scaling out can help process a data job faster, scalability alone does not guarantee that resources will be reduced or powered off when the job completes. The scenario explicitly needs automatic de-provisioning during idle periods, which is the defining trait of elasticity rather than scalability.
When this WOULD be correct
A company expects steady growth in user traffic over the next year and wants to add more virtual machines to handle the increased load. The question asks for the characteristic that allows resources to be added as demand grows, without focusing on automatic removal or cost optimization.
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.
✓ElasticityCorrect answer▾
Why this is correct
Elasticity is the cloud property that lets a system automatically provision and release compute resources to match real-time workload demand. For a nightly data processing job, resources can be spun up at the scheduled start time and deprovisioned when the job finishes, so the business pays only for the active processing window. This dynamic start/stop behavior directly lowers cost, which is exactly what this scenario requires.
✗High availabilityWrong answer — click to see why▾
Why this is wrong here
High availability ensures that resources remain operational and accessible during failures, but it does not address the automatic starting and stopping of compute resources based on demand to reduce costs.
★ When this WOULD be the correct answer
A question asks: 'A company needs to ensure its application remains accessible despite a regional outage. Which characteristic should they prioritize?' In that context, high availability would be correct.
Why candidates choose this
Candidates may confuse high availability with the ability to handle variable workloads, mistakenly thinking that keeping resources always available is the same as automatically provisioning them only when needed.
✗ScalabilityWrong answer — click to see why▾
Why this is wrong here
Scalability refers to the ability to increase or decrease resources to handle varying loads, but it typically involves manual or planned scaling, not automatic start/stop based on a schedule. The requirement is for automatic provisioning and deprovisioning of resources without manual intervention, which is elasticity.
★ When this WOULD be the correct answer
A company expects steady growth in user traffic over the next year and wants to add more virtual machines to handle the increased load. The question asks for the characteristic that allows resources to be added as demand grows, without focusing on automatic removal or cost optimization.
Why candidates choose this
Candidates often confuse scalability with elasticity because both involve adjusting resources. They may think 'scaling up/down' includes automatic start/stop, but scalability is more about capacity planning, while elasticity specifically handles dynamic, automatic provisioning.
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?”
Go deeper
Related to this question
Learn chapter
What is Cloud Computing?
Key term
Cloud computing
Cloud computing is the on-demand delivery of IT resources over the internet, allowing users to access computing power, storage, and applications without owning physical hardware.
Key term
Elasticity
Elasticity is the ability of a cloud system to automatically add or remove computing resources (like servers, storage, or bandwidth) in response to real-time changes in demand.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This AZ-900 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the AZ-900 exam.