AZ-900 Describe cloud concepts Practice Test 9 — 15 Questions

Question 1

A development team frequently needs to create and tear down test environments. In their on-premises datacenter, they must submit a ticket to the IT operations team, which often takes several days to provision the required servers. After migrating to Azure, developers can now create virtual machines, databases, and other resources directly through the Azure portal or using PowerShell scripts, without any interaction from the IT operations team. This ability to provision cloud resources directly is a direct example of which fundamental characteristic of cloud computing?

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

Accepted Answer

On-demand self-service. The scenario describes developers provisioning virtual machines, databases, and other resources directly through the Azure portal or PowerShell scripts without needing to interact with the IT operations team. This is the definition of on-demand self-service, a core characteristic of cloud computing defined by NIST (SP 800-145) as a consumer being able to unilaterally provision computing capabilities without requiring human interaction with each service provider.

Answer

Resource pooling

Answer

Measured service

Answer

Rapid elasticity

Question 2

A company's field employees use a custom mobile app to upload sales data from their smartphones while at client sites. The app connects to an Azure-hosted backend API. The company's IT team notes that the mobile app can connect to the Azure service using standard HTTPS from any location with internet connectivity, without requiring a VPN. This ability to access cloud resources over the internet from various devices and locations is an example of which key characteristic of cloud computing?

Accepted Answer

Broad network access. Broad network access means cloud resources can be accessed over standard network protocols (like HTTPS) from a wide range of devices (smartphones, laptops, tablets) and locations without requiring a private connection such as a VPN. In this scenario, the mobile app uses HTTPS to reach the Azure backend API from any internet-connected location, which directly matches the NIST definition of broad network access.

Answer

Rapid elasticity

Answer

Measured service

Answer

Resource pooling

Question 3

A company plans to migrate a steady-state application to Azure. The application requires a fixed number of virtual machines running 24/7 for the next three years. The company wants to minimize the total cost of ownership for these virtual machines over the three-year period. Which Azure pricing option should the company select when purchasing the virtual machines?

Accepted Answer

Reserved Instances. Reserved Instances (RIs) provide a significant discount (up to 72% compared to pay-as-you-go) in exchange for a one- or three-year commitment. Since the application requires a fixed number of VMs running 24/7 for exactly three years, RIs align perfectly with this predictable, steady-state workload, minimizing total cost of ownership.

Answer

Pay-as-you-go pricing

Answer

Spot Virtual Machines

Answer

Azure Hybrid Benefit

Question 4

A company is migrating a custom line-of-business application to Azure. The application handles sensitive customer data. The IT team is evaluating whether to deploy the application on Azure Virtual Machines (IaaS) or Azure App Service (PaaS). They want to understand the division of security responsibilities between Microsoft and the customer under the shared responsibility model. Which responsibility remains the customer's obligation regardless of whether they choose IaaS, PaaS, or SaaS?

Accepted Answer

Managing user access to the application data and ensuring data classification policies are enforced. Under the shared responsibility model, the customer is always responsible for managing access to data and enforcing data classification policies, regardless of whether the workload runs on IaaS, PaaS, or SaaS. This is because data ownership and the associated governance obligations (such as who can read, write, or modify sensitive customer data) remain with the customer. Microsoft secures the underlying infrastructure, but the customer must control who accesses the application data and how it is classified.

Answer

Applying operating system security patches and updates to virtual machines

Answer

Managing the physical server hardware, network switches, and datacenter cooling

Answer

Configuring and maintaining the application-level network load balancer for high availability

Question 5

A retail company migrates its e-commerce platform to Azure Virtual Machines. The workload is seasonal, with high traffic during holiday sales and low traffic otherwise. To manage costs, the IT team configures Azure Automation to power off VMs during low-traffic periods and power them back on when demand increases. The company's monthly bill reflects charges only for the hours each VM was actually running; no charges are incurred for the time the VMs were in the 'Stopped (deallocated)' state. This consumption-based billing model is a direct example of which fundamental characteristic of cloud computing?

Accepted Answer

Measured service. The scenario describes a consumption-based billing model where charges are incurred only for the hours each VM is actually running, and no charges apply when VMs are in the 'Stopped (deallocated)' state. This directly exemplifies the 'measured service' characteristic of cloud computing, where resource usage (e.g., compute hours) is metered and billed based on actual consumption, enabling pay-as-you-go pricing.

Answer

Rapid elasticity

Answer

Resource pooling

Answer

Broad network access

Question 6

A retail company runs its e-commerce platform on Azure App Service. The platform is configured with an autoscale rule that adds web server instances when CPU usage exceeds 75%. During a holiday flash sale, traffic surges from a baseline of 1,000 concurrent users to over 100,000 concurrent users within minutes. The platform automatically provisions additional instances to handle the load, and once the sale ends, it scales back down. This ability to rapidly adjust resources to meet varying demand is a direct example of which fundamental characteristic of cloud computing?

Accepted Answer

Rapid elasticity. Rapid elasticity is the cloud characteristic that enables resources to scale out (add instances) and scale in (remove instances) automatically and quickly in response to demand changes. In this scenario, the autoscale rule on Azure App Service detects CPU usage exceeding 75% and provisions additional web server instances within minutes to handle the surge from 1,000 to over 100,000 concurrent users, then scales back down after the flash sale ends. This dynamic, near-instantaneous adjustment of capacity is the direct embodiment of rapid elasticity, distinguishing it from manual provisioning or fixed capacity models.

Answer

On-demand self-service

Answer

Measured service

Answer

Resource pooling

Question 7

A healthcare organization migrates its patient data management application to Azure. The organization's compliance team learns that Azure's underlying physical infrastructure, including servers and storage, is shared by many customers globally. The team is concerned about data leakage and wants to understand which fundamental cloud computing characteristic allows the provider to share physical hardware among multiple tenants while ensuring that each tenant's data and compute resources remain logically isolated and secure from one another.

Accepted Answer

Resource pooling. Resource pooling is the correct answer because it is the fundamental cloud computing characteristic that enables a provider to serve multiple customers (tenants) from the same physical hardware while maintaining logical isolation. In Azure, this is achieved through hypervisor-level virtualization (e.g., Hyper-V) where each tenant's virtual machines and data are isolated at the kernel and memory level, preventing cross-tenant data leakage even though the underlying servers and storage are shared.

Answer

Rapid elasticity

Answer

Measured service

Answer

Broad network access

Question 8

A manufacturing company is evaluating whether to migrate its on-premises workloads to Azure. The IT team calculates that the total cost of running the equivalent compute and storage resources in Azure is lower than operating its own datacenter. They attribute this cost advantage to the fact that Azure purchases servers, networking gear, and power in massive quantities and passes the savings on to customers by spreading the fixed costs across a vast number of tenants. This cost-saving benefit is a direct illustration of which cloud computing concept?

Accepted Answer

Economies of scale. The scenario describes a cost advantage that arises because Azure buys hardware and energy in bulk, reducing per-unit costs and spreading fixed expenses across many customers. This is the direct definition of economies of scale, a core cloud concept where large-scale operations lower the average cost per unit, enabling providers to offer services at a lower price than individual organizations could achieve on-premises.

Answer

Resource pooling

Answer

Measured service

Answer

Rapid elasticity

Question 9

A retail company experiences fluctuating customer traffic throughout the year. During peak seasons, traffic can increase by 300% for a few weeks. The company wants to pay only for the compute resources it uses, without needing to invest in permanent infrastructure to handle peak loads. Which cloud computing characteristic best supports this requirement?

Accepted Answer

Elasticity. Elasticity is the cloud computing characteristic that allows resources to automatically scale up or down based on demand. In this scenario, the retail company needs to handle a 300% traffic spike during peak seasons without permanently provisioning infrastructure, and elasticity enables dynamic provisioning and de-provisioning of compute resources to match the fluctuating load, ensuring they pay only for what they use.

Answer

High availability

Answer

Fault tolerance

Answer

Geo-redundancy

Question 10

A company plans to migrate a line-of-business application to Azure. The application will run on a virtual machine (IaaS). The company wants to ensure that the operating system is kept up to date with security patches. According to the shared responsibility model, who is primarily responsible for applying these patches?

Accepted Answer

The customer, because the customer manages the guest operating system and is responsible for patching it.. In the shared responsibility model for IaaS, the customer retains control over the guest operating system, including applying security patches. Microsoft manages the physical host and hypervisor but does not patch the OS running inside the VM. Therefore, the customer is primarily responsible for keeping the OS up to date.

Answer

Microsoft, because they manage all operating system updates in Azure.

Answer

Both Microsoft and the customer share responsibility equally for operating system patching.

Answer

The cloud service provider, as a general rule for all services in Azure.

Question 11

A healthcare company is planning to migrate its on-premises data center to Azure. The CFO wants to shift from making large upfront hardware purchases to paying for IT resources as an ongoing operational cost. Which cloud computing benefit does this scenario describe?

Accepted Answer

Operational expenditure (OpEx). The scenario describes shifting from capital expenditure (CapEx) for upfront hardware purchases to operational expenditure (OpEx) for ongoing, pay-as-you-go IT resource consumption. This is a core financial benefit of cloud computing, where costs are treated as variable operating expenses rather than fixed capital investments.

Answer

High availability

Answer

Elasticity

Answer

Fault tolerance

Question 12

A financial services firm uses a hybrid cloud strategy. They run customer-facing applications in a public cloud and store sensitive customer data in an on-premises data center to meet regulatory compliance. The firm wants to allow its applications in the public cloud to securely access the on-premises data when needed. Which cloud deployment model best describes this setup?

Accepted Answer

Hybrid cloud. The scenario describes a hybrid cloud deployment model, which combines a public cloud (for customer-facing applications) with an on-premises private cloud (for sensitive data storage) and enables secure connectivity between them, typically through VPN or dedicated circuits like Azure ExpressRoute. This allows the firm to meet regulatory compliance by keeping sensitive data on-premises while leveraging public cloud scalability for applications.

Answer

Public cloud

Answer

Private cloud

Answer

Community cloud

Question 13

A company runs a web application on Azure virtual machines. The application experiences unpredictable traffic patterns with occasional sharp spikes. The operations team wants to configure the infrastructure so that the number of running virtual machines automatically increases during spikes and decreases during low traffic periods, without manual intervention. Which cloud computing characteristic does this requirement describe?

Accepted Answer

Elasticity. Elasticity is the cloud computing characteristic that enables resources to automatically scale out (increase) during demand spikes and scale in (decrease) during low traffic periods, matching capacity to workload in real time. In Azure, this is implemented via Virtual Machine Scale Sets with autoscale rules based on metrics like CPU or memory thresholds, allowing the number of VMs to adjust without manual intervention.

Answer

High availability

Answer

Fault tolerance

Answer

Geographic distribution

Question 14

A company subscribes to a SaaS-based customer relationship management (CRM) application hosted in the cloud. The CRM provider manages the application, runtime, and infrastructure. The company's employees access the CRM via a web browser. According to the shared responsibility model, which security responsibility belongs solely to the company?

Accepted Answer

Safeguarding the company's customer data and user identities.. In a SaaS model, the provider manages the application, runtime, and infrastructure, including patching the OS and physical security. The customer retains responsibility for what they bring into the cloud: their data and user identities. Option C is correct because safeguarding customer data and managing user identities (e.g., via Azure AD) is solely the company's responsibility under the shared responsibility model.

Answer

Patching the underlying operating system of the CRM servers.

Answer

Managing network access controls to the CRM application.

Answer

Ensuring physical security of the data centers hosting the CRM.

Question 15

A company runs a legacy database on a single Azure virtual machine. The database is experiencing performance issues as the dataset grows. The IT team decides to increase the virtual machine size from Standard_D2s_v3 (2 vCPUs, 8 GB RAM) to Standard_D8s_v3 (8 vCPUs, 32 GB RAM) to improve performance. This process is an example of which cloud computing concept?

Accepted Answer

Vertical scaling. Vertical scaling (also known as scaling up) involves increasing the capacity of a single resource, such as adding more vCPUs and RAM to an existing virtual machine. In this scenario, the IT team is resizing the Azure VM from Standard_D2s_v3 to Standard_D8s_v3, which increases the compute and memory resources of the same instance. This directly matches the definition of vertical scaling, where performance is improved by upgrading the existing machine rather than adding more machines.

Answer

Horizontal scaling

Answer

Elasticity

Answer

High availability