AZ-900 Describe cloud concepts Practice Test 3 — 15 Questions

Question 1

A company is moving from an on-premises data center to the cloud. Previously, they paid a large upfront sum for servers and storage, plus annual maintenance fees. Now they pay a monthly subscription based on the amount of compute and storage they actually use. This shift represents moving from which type of expenditure to which?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

From CapEx to OpEx. This scenario describes a shift from Capital Expenditure (CapEx) to Operational Expenditure (OpEx). CapEx involves upfront purchases of physical assets like servers and storage, which are capitalized and depreciated over time. OpEx, on the other hand, is a pay-as-you-go model where costs are incurred based on actual usage, such as monthly cloud subscription fees for compute and storage resources.

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From OpEx to CapEx

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From direct cost to indirect cost

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From variable cost to fixed cost

Question 2

A startup wants to run a web application without purchasing or managing any servers. They only want to upload their code and let the cloud provider handle everything from the runtime to scaling. Which cloud service model best fits this requirement?

Accepted Answer

Platform as a Service (PaaS). Platform as a Service (PaaS) is the correct model because it provides a fully managed hosting environment where the startup can deploy their web application code without needing to provision or manage underlying servers, operating systems, or runtime infrastructure. Azure App Service is a prime example of PaaS that handles automatic scaling, load balancing, and patching, allowing developers to focus solely on code.

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Infrastructure as a Service (IaaS)

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Software as a Service (SaaS)

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Function as a Service (FaaS)

Question 3

A hospital stores patient data in the cloud. They are concerned about physical security at the datacenter. Which aspect of the shared responsibility model describes the cloud provider's obligation to secure the physical infrastructure?

Accepted Answer

Security of physical hardware. In the shared responsibility model, the cloud provider is always responsible for the physical security of the datacenter, including the physical hardware, environmental controls (power, cooling), and physical access controls. This is a foundational principle of the model: the provider secures the physical layer, while the customer secures what they deploy on top of it.

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Security of the network infrastructure

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Security of customer data

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Security of operating systems

Question 4

A company runs a seasonal e-commerce application. During the holiday season, demand spikes significantly, but the company does not want to pay for idle resources the rest of the year. They want the cloud to automatically add or remove compute resources based on real-time demand. Which cloud computing characteristic does this scenario best describe?

Accepted Answer

Elasticity. Elasticity is the cloud characteristic that enables automatic scaling of resources up or down in real-time to match demand. In this scenario, the e-commerce application needs to add compute resources during holiday spikes and remove them when demand drops, avoiding paying for idle resources. This aligns directly with elasticity, which is often implemented via auto-scaling groups and load balancers that adjust capacity based on metrics like CPU utilization or request count.

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Scalability

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High availability

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Disaster recovery

Question 5

A company is moving its on-premises data center to the cloud. Previously, they purchased servers and paid for maintenance. Now they pay a monthly subscription for compute and storage based on actual usage. This is an example of shifting from capital expenditure (CapEx) to which type of expenditure?

Accepted Answer

Operating expenditure (OpEx). This scenario describes a shift from upfront capital investment in physical servers and maintenance (CapEx) to a pay-as-you-go model where costs are incurred based on actual usage. In cloud computing, this is the definition of operating expenditure (OpEx), as the company pays a recurring monthly subscription for compute and storage resources rather than making a large initial purchase.

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Variable expenditure

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Direct expenditure

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Indirect expenditure

Question 6

A hospital stores patient health records in the cloud. They are responsible for encrypting the data before storing it, while the cloud provider is responsible for securing the physical datacenter. Which cloud model is being described?

Accepted Answer

Shared responsibility model. The scenario describes a division of security responsibilities: the hospital encrypts data (customer responsibility) and the cloud provider secures the physical datacenter (provider responsibility). This is the core definition of the shared responsibility model, where security obligations are split based on the cloud service model (IaaS, PaaS, SaaS) and the customer's control over the data and configurations.

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Community cloud

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Hybrid cloud

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Private cloud

Question 7

A startup wants to run a web application without managing the underlying servers. They only want to upload their code and let the cloud provider handle the runtime, scaling, and maintenance. Which cloud service model is this?

Accepted Answer

Platform as a Service (PaaS). Platform as a Service (PaaS) is the correct model because it provides a managed hosting environment where the startup can deploy their web application code without managing the underlying servers, operating systems, or runtime infrastructure. Azure App Service is a prime example of PaaS, handling automatic scaling, patching, and load balancing while the customer only focuses on code and data.

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Infrastructure as a Service (IaaS)

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Software as a Service (SaaS)

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Function as a Service (FaaS)

Question 8

A company is evaluating cloud providers. They want to ensure that their data remains within a specific country due to legal requirements. Which cloud computing concept is most directly related to this requirement?

Accepted Answer

Data sovereignty. Data sovereignty is the concept that data is subject to the laws and governance structures of the country where it is physically stored. For a company with legal requirements to keep data within a specific country, this concept directly dictates where cloud providers must locate their data centers and how they handle data residency. Azure, for example, offers region pairs and data residency commitments through its Trust Center to help customers meet such compliance obligations.

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Latency

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High availability

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Elasticity

Question 9

A company runs a web application that experiences unpredictable traffic spikes. They want the cloud to automatically increase the number of virtual machine instances during high demand and decrease them when demand drops, without manual intervention. Which cloud computing characteristic does this describe?

Accepted Answer

Elasticity. Elasticity is the cloud characteristic that automatically scales resources up or down based on demand. In this scenario, the web application experiences unpredictable traffic spikes, and the cloud automatically adjusts the number of VM instances without manual intervention, which is the definition of elasticity. Scalability is the ability to handle growth, but it often requires manual intervention or is not automatic.

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Scalability

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High availability

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Fault tolerance

Question 10

A hospital stores patient data in the cloud. The hospital is responsible for encrypting the data before uploading, managing user access, and complying with healthcare regulations. The cloud provider is responsible for securing the physical datacenter, network infrastructure, and hypervisor. This model describes which concept?

Accepted Answer

Shared responsibility model. The scenario explicitly divides security responsibilities between the hospital (data encryption, access management, regulatory compliance) and the cloud provider (physical datacenter, network, hypervisor). This division of security obligations is the core definition of the shared responsibility model, which applies across all cloud service models (IaaS, PaaS, SaaS) but is most clearly illustrated here where the customer retains control over data and identity layers.

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Infrastructure as a Service (IaaS)

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Platform as a Service (PaaS)

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Software as a Service (SaaS)

Question 11

A company is migrating its on-premises workloads to Azure. Previously, they purchased servers every three years as a large capital investment. Now, they pay a monthly subscription for virtual machines based on actual usage, with no long-term commitment. Which type of cloud expenditure model does this represent?

Accepted Answer

Capital expenditure (CapEx) to operational expenditure (OpEx). This scenario describes a shift from Capital Expenditure (CapEx), where the company made large upfront investments in hardware every three years, to Operational Expenditure (OpEx), where they pay a monthly subscription for Azure virtual machines based on actual usage with no long-term commitment. This is a core benefit of cloud computing, converting fixed, upfront costs into variable, ongoing expenses that align with consumption.

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Operational expenditure (OpEx) to capital expenditure (CapEx)

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Pay-as-you-go to reserved

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Consumption-based to fixed cost

Question 12

A company wants to run some applications in its own on-premises datacenter for compliance reasons, while also using cloud services for burst capacity and development/testing. Which cloud deployment model should they adopt?

Accepted Answer

Hybrid cloud. The hybrid cloud model is correct because it combines on-premises infrastructure (private cloud) with public cloud services, enabling the company to keep sensitive applications in its own datacenter for compliance while using the public cloud for burst capacity and development/testing. This directly matches the scenario's requirement for a unified environment that spans both local and cloud resources.

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Private cloud

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Public cloud

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Community cloud

Question 13

An Azure service guarantees 99.95% uptime for virtual machines deployed with two or more instances in an availability set. If the monthly uptime falls below this percentage, customers can receive a service credit. What does this guarantee represent?

Accepted Answer

Service Level Agreement (SLA). This guarantee is a Service Level Agreement (SLA) because it is a formal, published commitment from Microsoft regarding the uptime percentage (99.95%) for a specific Azure service (Virtual Machines in an Availability Set), and it includes a financial remedy (service credits) if the commitment is not met. SLAs are contractual agreements that define the level of service a customer can expect and the compensation for failures.

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Service Level Objective (SLO)

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Service Level Indicator (SLI)

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Service Health

Question 14

A company currently budgets for maximum capacity to handle peak loads, resulting in underutilized resources during off-peak times. They want a model where they can quickly adjust resources up or down based on demand. Which cloud characteristic directly addresses this concern?

Accepted Answer

Elasticity. Elasticity is the cloud characteristic that enables automatic scaling of resources up or down in response to real-time demand. This directly addresses the company's need to avoid over-provisioning for peak loads while still being able to handle spikes without manual intervention, typically implemented through auto-scaling policies in services like Azure Virtual Machine Scale Sets or Azure App Service autoscale.

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High availability

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Geo-redundancy

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Fault tolerance

Question 15

A company wants to use cloud services to temporarily increase compute capacity for a promotional event, then reduce resources afterward. They want to pay only for the extra resources used during that event. Which cloud benefit does this scenario best describe?

Accepted Answer

Scalability. This scenario describes scalability, specifically the ability to scale out (increase capacity) for a promotional event and then scale in (reduce resources) afterward, paying only for what is used. Azure Auto Scaling (e.g., Virtual Machine Scale Sets or Azure App Service autoscale) automatically adjusts compute resources based on demand, aligning with the pay-as-you-go model. The key is that resources are temporarily increased and then reduced, which is the hallmark of scalability, not just the ability to handle load.

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High availability

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Agility

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Reliability