AZ-900 Describe cloud concepts Practice Question
A company's IT manager is evaluating a public cloud provider. The provider's data center contains powerful physical servers that host virtual machines from thousands of different organizations. The manager is concerned about security, but the provider assures that each organization's VMs are logically isolated and cannot access each other's data, even though they share the same hardware. Which essential characteristic of cloud computing does this scenario best describe?
⚠ Common exam trap
A common mix-up: candidates confuse 'resource pooling' with 'rapid elasticity' because both involve shared infrastructure, but resource pooling is about multi-tenancy and logical isolation, while rapid elasticity is about dynamic scaling of resources.
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
✓
Resource pooling
The scenario describes resource pooling because the provider's physical servers host VMs from multiple organizations, and logical isolation ensures each tenant's data remains separate. Resource pooling is the cloud characteristic where computing resources (e.g., storage, processing, memory) are aggregated to serve multiple customers using a multi-tenant model, with physical and virtual resources dynamically assigned and reassigned according to demand. The provider's assurance of logical isolation (e.g., via hypervisor-level segmentation or VLANs) is a direct implementation of resource pooling's security boundary.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Rapid elasticity
Why it's wrong here
Rapid elasticity is not the right description because the scenario focuses on shared physical servers, not on the ability to scale resources quickly. Elasticity means cloud capabilities are provisioned and released automatically to match workload peaks, such as adding more VMs during heavy traffic. The prompt's key detail — multiple customers on the same physical hardware — points to resource pooling rather than time-based resource adjustment.
When this WOULD be correct
A company's web application experiences unpredictable traffic spikes. The cloud provider automatically provisions additional virtual machines during peak times and deprovisions them when demand drops, ensuring performance without manual intervention. This scenario describes rapid elasticity.
- ✗
Measured service
Why it's wrong here
Measured service is not correct because the scenario does not involve metering, monitoring, or billing of consumption. Cloud providers automatically measure resource usage through metrics like CPU time, network bandwidth, and storage gigabytes, enabling a pay-per-use model. Resource sharing among multiple customers is an infrastructure architecture decision that can exist even without usage metering, so it is not the characteristic being illustrated.
When this WOULD be correct
A company wants to pay only for the compute resources it actually uses, with detailed usage reports. The cloud provider meters CPU hours, storage, and network traffic, and bills accordingly. This scenario tests understanding of measured service.
- ✗
Broad network access
Why it's wrong here
Broad network access is wrong because the scenario is about underlying hardware sharing, not about how customers reach cloud services. Broad network access means services are available over the network through standard protocols and capable of being consumed by various devices like phones, tablets, and workstations. The logical separation of customer environments on the same physical server is a characteristic of resource pooling, not a connectivity feature.
When this WOULD be correct
A question describing a cloud service accessible from various devices (e.g., laptops, smartphones, tablets) via the internet, without requiring a dedicated connection, would make broad network access the correct answer.
- ✓
Resource pooling
Why this is correct
Resource pooling is correct because cloud providers use virtualization to aggregate physical compute, storage, and networking resources into a shared pool that serves multiple tenants. Customers receive logical isolation through hypervisor partitions, VLANs, and container boundaries, so their data does not mix even though they run on the same hardware infrastructure. This shared multi-tenant architecture is the core of the scenario, not any dynamic scaling, usage metering, or network access characteristic.
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.
✓Resource poolingCorrect answer▾
Why this is correct
Resource pooling is correct because cloud providers use virtualization to aggregate physical compute, storage, and networking resources into a shared pool that serves multiple tenants. Customers receive logical isolation through hypervisor partitions, VLANs, and container boundaries, so their data does not mix even though they run on the same hardware infrastructure. This shared multi-tenant architecture is the core of the scenario, not any dynamic scaling, usage metering, or network access characteristic.
✗Rapid elasticityWrong answer — click to see why▾
Why this is wrong here
Rapid elasticity refers to the ability to quickly scale resources up or down based on demand, not to the logical isolation of shared physical resources among multiple tenants.
★ When this WOULD be the correct answer
A company's web application experiences unpredictable traffic spikes. The cloud provider automatically provisions additional virtual machines during peak times and deprovisions them when demand drops, ensuring performance without manual intervention. This scenario describes rapid elasticity.
Why candidates choose this
Candidates may confuse the dynamic allocation of resources in resource pooling with the scaling aspect of rapid elasticity, as both involve adjusting resources based on usage.
✗Measured serviceWrong answer — click to see why▾
Why this is wrong here
Measured service refers to the ability to monitor, control, and report resource usage for billing and optimization, not to the logical isolation of VMs sharing physical hardware.
★ When this WOULD be the correct answer
A company wants to pay only for the compute resources it actually uses, with detailed usage reports. The cloud provider meters CPU hours, storage, and network traffic, and bills accordingly. This scenario tests understanding of measured service.
Why candidates choose this
Candidates may confuse 'measured' with 'metered' or 'managed' isolation, or think that security monitoring is a form of measurement.
✗Broad network accessWrong answer — click to see why▾
Why this is wrong here
Broad network access refers to the ability to access cloud services over the network via standard protocols (e.g., internet, VPN). The scenario describes logical isolation of VMs on shared hardware, which is resource pooling, not network access.
★ When this WOULD be the correct answer
A question describing a cloud service accessible from various devices (e.g., laptops, smartphones, tablets) via the internet, without requiring a dedicated connection, would make broad network access the correct answer.
Why candidates choose this
Candidates may confuse 'broad network access' with the idea that multiple organizations access the same cloud provider's network, but the key here is the isolation of VMs, not the access method.
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?”
Visual reference
Go deeper
Related to this question
Learn chapter
What is Cloud Computing?
Key term
Hypervisor
A hypervisor is software that creates and runs virtual machines by allowing multiple operating systems to share a single hardware host.
Key term
Security
Security in IT is the practice of protecting systems, networks, and data from unauthorized access, damage, or theft.
About these practice questions
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JA
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.