AZ-900 Describe cloud concepts Practice Test 5 — 15 Questions

Question 1

A company can provision virtual machines in Azure without submitting a request or waiting for hardware procurement. Which cloud characteristic does this describe?

Accepted Answer

On-demand self-service. On-demand self-service allows users to provision virtual machines and other cloud resources automatically without requiring human interaction with the service provider. This eliminates the need for submitting a formal request or waiting for hardware procurement, as the provisioning is handled through a web portal, API, or CLI.

Answer

Rapid elasticity

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Measured service

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Resource pooling

Question 2

A company wants to be able to increase and decrease resources automatically based on demand without manual intervention. Which cloud characteristic does this describe?

Accepted Answer

Rapid elasticity. Rapid elasticity is the cloud characteristic that enables resources to be automatically and dynamically scaled out (increased) or scaled in (decreased) in response to real-time demand, without requiring manual intervention. This is typically implemented through autoscaling policies that monitor metrics like CPU utilization or request count and trigger provisioning or de-provisioning of virtual machines or containers via APIs. The key differentiator is that scaling happens automatically and often in near real-time, matching the elasticity definition in NIST SP 800-145.

Answer

Measured service

Answer

Resource pooling

Answer

On-demand self-service

Question 3

A company uses a public cloud provider that shares the same physical infrastructure among many customers. This allows the provider to offer lower prices due to economies of scale. Which cloud characteristic describes the sharing of infrastructure?

Accepted Answer

Resource pooling. Resource pooling is the cloud characteristic that allows a provider to serve multiple customers from the same physical infrastructure, using multi-tenant models. This sharing enables economies of scale because the provider can amortize hardware costs across many tenants, reducing per-customer pricing. The scenario directly describes multi-tenancy and shared infrastructure, which is the essence of resource pooling.

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Measured service

Answer

Rapid elasticity

Answer

On-demand self-service

Question 4

A company is moving its IT infrastructure to the cloud to avoid large upfront hardware purchases and instead pay a predictable monthly fee. Which cloud benefit does this represent?

Accepted Answer

Consumption-based pricing. Consumption-based pricing is a cloud benefit where customers pay only for the resources they use (e.g., compute hours, storage GBs) rather than making large upfront capital expenditures. This model shifts costs from CapEx to OpEx, enabling predictable monthly billing based on actual consumption. The scenario explicitly describes avoiding upfront hardware purchases and paying a predictable monthly fee, which directly aligns with this pay-as-you-go model.

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High availability

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Elasticity

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Scalability

Question 5

A company runs a global e-commerce platform. During a flash sale, demand surges from 10,000 users to 500,000 users in minutes. The platform automatically provisions additional servers to handle the load and deprovisions them after the sale. Which cloud characteristic is most directly demonstrated?

Accepted Answer

Elasticity. Elasticity is the ability of a cloud system to automatically scale resources up or down based on demand. In this scenario, the platform provisions additional servers during the flash sale and deprovisions them afterward, directly demonstrating elasticity. This contrasts with other characteristics like high availability, which focuses on uptime, not dynamic scaling.

Answer

High availability

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Fault tolerance

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Geographic distribution

Question 6

A company wants to understand who is responsible for securing the operating system on an Azure virtual machine. According to the shared responsibility model, who is responsible?

Accepted Answer

Microsoft is responsible for the physical host and network, while the customer is responsible for the guest OS and applications.. Under the shared responsibility model for IaaS like Azure VMs, Microsoft secures the physical datacenter, host OS, and network infrastructure, while the customer is responsible for securing the guest OS (e.g., applying patches, configuring firewalls) and any applications running on the VM. This division is explicit in Azure's documentation, where the customer retains control over the OS and software stack.

Answer

Microsoft is responsible for all security.

Answer

The customer is responsible for all security.

Answer

Responsibility is split 50/50.

Question 7

A startup expects rapid growth and wants its cloud infrastructure to automatically add or remove compute resources based on real-time demand without manual intervention. Which cloud characteristic does this describe?

Accepted Answer

Elasticity. Elasticity is the cloud characteristic that enables automatic scaling of compute resources up or down in response to real-time demand. This startup's requirement to add or remove resources without manual intervention directly matches the definition of elasticity, which is a core benefit of cloud computing.

Answer

High availability

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Fault tolerance

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Disaster recovery

Question 8

A company uses Azure SQL Database (PaaS). According to the shared responsibility model, who is responsible for applying security patches to the underlying operating system that runs the database service?

Accepted Answer

Microsoft. Microsoft is responsible for applying security patches to the underlying operating system that hosts Azure SQL Database because it is a Platform as a Service (PaaS) offering. In the PaaS shared responsibility model, the cloud provider manages the infrastructure, including the OS, runtime, and network, while the customer is responsible for data and access management. Azure SQL Database abstracts the OS layer entirely, so Microsoft handles all patching and maintenance to ensure security and compliance.

Answer

The customer

Answer

Both

Answer

Neither

Question 9

A company transitions from on-premises IT, where they purchased servers upfront, to Azure, where they pay a monthly subscription for virtual machines. This is an example of moving from capital expenditure (CapEx) to which type of expenditure?

Accepted Answer

Operating expenditure (OpEx). Moving from purchasing servers upfront (CapEx) to paying a monthly subscription for Azure virtual machines shifts costs to an operational expense (OpEx). This is because Azure's pay-as-you-go model charges for compute resources as they are consumed, with no large initial investment, aligning with OpEx accounting where costs are incurred and deducted in the same period.

Answer

Variable expenditure

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Consumption-based expenditure

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Fixed expenditure

Question 10

A cloud provider purchases hardware in bulk and shares physical infrastructure among many customers, which allows them to offer lower prices per customer. This benefit is known as:

Accepted Answer

Economies of scale. Economies of scale refer to the cost advantage that cloud providers achieve by purchasing hardware in bulk and sharing physical infrastructure across many customers. This reduces the per-unit cost of compute, storage, and networking resources, enabling providers to offer lower prices per customer. The scenario directly describes the cost benefits of large-scale operations, which is the defining characteristic of economies of scale.

Answer

Elasticity

Answer

Resource pooling

Answer

High availability

Question 11

A company wants to move from paying large upfront costs for hardware to a model where they only pay for what they use on a monthly basis. This represents a shift from CapEx to which type of expenditure?

Accepted Answer

Operational expenditure (OpEx). This scenario describes a shift from Capital Expenditure (CapEx), where large upfront costs are incurred for hardware, to Operational Expenditure (OpEx), where costs are based on actual usage and billed monthly. In cloud computing, OpEx aligns with the consumption-based model, where you pay only for resources consumed (e.g., compute hours, storage GB) without upfront commitments. This is a core financial benefit of cloud services like Azure, enabling variable costs instead of fixed capital investments.

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Direct expenditure

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Indirect expenditure

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Capital expenditure

Question 12

A startup wants to avoid managing physical servers and instead focus on developing their application. Which cloud service model provides them with the most control over the operating system and applications while still not managing hardware?

Accepted Answer

Infrastructure as a Service (IaaS). Infrastructure as a Service (IaaS) provides virtualized computing resources over the internet, giving the startup full control over the operating system, storage, and deployed applications without managing the underlying physical hardware. This model is ideal for a startup that wants to avoid hardware maintenance while retaining the flexibility to configure and manage their own OS and application stack.

Answer

Software as a Service (SaaS)

Answer

Platform as a Service (PaaS)

Answer

Functions as a Service (FaaS)

Question 13

A company deploys their application across multiple availability zones in an Azure region. This is done to improve which aspect of the application?

Accepted Answer

High availability. Deploying an application across multiple availability zones within an Azure region ensures that if one zone experiences an outage (e.g., due to power failure or network disruption), the application can continue serving traffic from the remaining zones. This architecture directly improves high availability by eliminating a single point of failure at the datacenter level, typically achieving a service-level agreement (SLA) of 99.99% for virtual machines when using two or more instances across zones.

Answer

Scalability

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Elasticity

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Cost efficiency

Question 14

A company wants to ensure their application remains available even if an entire Azure region experiences an outage. Which Azure feature should they implement?

Accepted Answer

Region pairs. Region pairs are designed to provide resilience against a complete Azure region outage by pairing each region with another region in the same geography (e.g., East US paired with West US). If one region fails, Azure can fail over services like storage (GRS) and SQL Database (Geo-Replication) to the paired region, ensuring application availability. This is the only option that protects against an entire region failure, as it leverages physically separate datacenters with independent power, cooling, and networking.

Answer

Availability sets

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Availability zones

Answer

Load balancer

Question 15

A company wants to use a cloud service that provides a fully managed database, including automated backups, patching, and high availability, without managing any underlying servers. Which cloud service model is this?

Accepted Answer

Platform as a Service (PaaS). This scenario describes a fully managed database service where the provider handles backups, patching, and high availability, and the customer does not manage any underlying servers. This is the definition of Platform as a Service (PaaS), which provides a managed platform (including database engines like Azure SQL Database) where the customer only manages data and schema, while the provider handles the OS, runtime, and infrastructure.

Answer

Infrastructure as a Service (IaaS)

Answer

Software as a Service (SaaS)

Answer

Container as a Service (CaaS)