AZ-900 Describe cloud concepts Practice Test 11 — 15 Questions

Question 1

A company hosts a web application on a single Azure virtual machine. Over the past month, the application's CPU utilization has consistently remained above 90%, causing slow response times. The administrator plans to modify the virtual machine's size from Standard_D2s_v3 (2 vCPUs) to Standard_D8s_v3 (8 vCPUs) to improve performance. Which scaling method does this change represent?

Accepted Answer

Vertical scaling (scaling up). Vertical scaling (scaling up) increases the power of an existing resource by upgrading its size or capacity. In this scenario, changing the virtual machine from Standard_D2s_v3 (2 vCPUs) to Standard_D8s_v3 (8 vCPUs) adds more CPU cores to the same VM, which is a classic example of scaling up. This approach improves performance without adding additional VM instances.

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Horizontal scaling (scaling out)

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Elastic scaling

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Auto-scaling

Question 2

A company uses Azure to host its virtual machines and storage. The company receives a monthly invoice that charges based on the exact number of virtual machine hours and gigabytes of storage consumed. No upfront payment is required. Which characteristic of cloud computing does this billing model represent?

Accepted Answer

Measured service. The billing model charges based on exact virtual machine hours and gigabytes of storage consumed, with no upfront payment. This directly reflects the measured service characteristic of cloud computing, where resource usage is metered, monitored, and billed according to consumption. Azure tracks usage metrics (e.g., VM runtime in hours, storage in GB-months) via its meters and generates invoices based on these precise measurements.

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Rapid elasticity

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Resource pooling

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On-demand self-service

Question 3

A company runs its production database on an Azure SQL Database (PaaS) and its custom application on an Azure virtual machine (IaaS). The company needs to ensure that operating system security patches are applied. According to the shared responsibility model, which resource requires the company to apply OS patches?

Accepted Answer

Azure virtual machine only. In the shared responsibility model, the customer is responsible for securing the operating system on IaaS resources like Azure virtual machines. Azure SQL Database is a PaaS service where Microsoft manages the underlying OS, including patch management. Therefore, only the Azure virtual machine requires the company to apply OS security patches.

Answer

Azure SQL Database only

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Both Azure SQL Database and the virtual machine

Answer

Neither resource requires the company to apply OS patches

Question 4

A company hosts a critical line-of-business application on Azure virtual machines. The application must remain available even if a single virtual machine fails due to hardware failure or operating system crash. The company deploys two virtual machines in an Availability Set and configures an Azure Load Balancer to distribute traffic. If one VM becomes unavailable, the Load Balancer automatically redirects traffic to the healthy VM. This configuration primarily demonstrates which benefit of cloud computing?

Accepted Answer

Reliability – ability to recover from failures and continue functioning. This configuration demonstrates reliability, a core cloud computing benefit, because the combination of an Availability Set and Azure Load Balancer ensures that the application remains operational even when a single VM fails due to hardware or OS issues. The Availability Set spreads VMs across fault domains and update domains to isolate failures, while the Load Balancer uses health probes to detect VM unavailability and redirect traffic only to healthy instances. This built-in redundancy and automatic failover capability directly aligns with the cloud's promise of high availability and fault tolerance.

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Elasticity – ability to scale resources up and down

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Security – protection against unauthorized access

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Cost efficiency – paying only for consumed resources

Question 5

A hospital maintains its patient records on physical servers located within its own on-premises data center due to strict data residency regulations that prohibit patient data from leaving the country. For analytical workloads that process only anonymized data, the hospital uses Azure virtual machines and Azure Synapse Analytics. This combination of on-premises and cloud resources best describes which cloud deployment model?

Accepted Answer

Hybrid cloud. The hospital uses a combination of on-premises physical servers (for patient records due to data residency regulations) and Azure cloud resources (VMs and Synapse Analytics for anonymized data analytics). This integration of on-premises and public cloud services is the defining characteristic of a hybrid cloud deployment model, as it allows workloads to span both environments while maintaining compliance.

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Public cloud

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Private cloud

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Community cloud

Question 6

A company is planning to migrate its customer relationship management (CRM) system to the cloud. The company is evaluating three service models: deploying the CRM on Azure Virtual Machines (IaaS), using Azure App Service to host a custom CRM web application (PaaS), and subscribing to a cloud-based CRM software like Dynamics 365 (SaaS). According to the Microsoft shared responsibility model, which of the following statements accurately describes the division of security responsibilities across these three options?

Accepted Answer

In all three models, Microsoft is responsible for securing the physical datacenter and network infrastructure. For IaaS, the customer is responsible for the guest OS and applications; for PaaS, the customer is responsible for the application code and data; for SaaS, the customer is responsible for data and user accounts.. Option A is correct because it accurately reflects the Microsoft shared responsibility model across IaaS, PaaS, and SaaS. In all three models, Microsoft is responsible for the physical datacenter and network infrastructure. For IaaS (Azure VMs), the customer manages the guest OS and applications; for PaaS (Azure App Service), the customer manages the application code and data; for SaaS (Dynamics 365), the customer manages data and user accounts. This division aligns with the principle that responsibility shifts from the customer to Microsoft as the service model moves from IaaS to SaaS.

Answer

In IaaS, Microsoft is responsible for the guest OS; in PaaS, Microsoft is responsible for the application code; in SaaS, the customer is responsible only for data.

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In IaaS, the customer is responsible for everything from the physical infrastructure up; in PaaS, Microsoft is responsible for the application runtime and the customer is responsible only for data; in SaaS, Microsoft is responsible for everything.

Answer

In all three models, the customer is responsible for securing all application code and data, while Microsoft secures the underlying hardware and operating system.

Question 7

A small business wants to migrate its IT infrastructure to Azure. The owner wants the ability to provision new virtual machines, storage accounts, and databases entirely through a web-based portal, without needing to submit a formal request or wait for an administrator to manually allocate resources. The owner expects resources to be available immediately after configuration. Which characteristic of cloud computing does this scenario best illustrate?

Accepted Answer

On-demand self-service. This scenario best illustrates on-demand self-service because the owner can provision virtual machines, storage accounts, and databases through a web-based portal (such as the Azure portal) without requiring human interaction with the cloud provider's administrators. The key characteristic is that resources are available immediately after configuration, eliminating the need for formal requests or manual allocation, which is the essence of on-demand self-service as defined by NIST SP 800-145.

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Broad network access

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Resource pooling

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Rapid elasticity

Question 8

A rapidly growing e-commerce company currently hosts its website on a single server in a US data center. Customers in Europe and Asia report slow load times and timeouts. The company wants to improve performance for global users without building and managing data centers worldwide. They plan to deploy the website on Azure virtual machines in multiple Azure regions (e.g., West Europe, Southeast Asia) and use Azure Traffic Manager to route users to the closest region. Which benefit of cloud computing does this approach primarily demonstrate?

Accepted Answer

Global reach. This approach primarily demonstrates global reach, which is the ability to deploy applications and services across multiple geographic regions to provide low-latency access to users worldwide. By hosting the website on Azure VMs in West Europe and Southeast Asia, and using Azure Traffic Manager to route users to the closest region based on DNS-based traffic routing (e.g., performance or geographic routing methods), the company leverages Azure's distributed infrastructure without building or managing its own data centers. This directly addresses the performance issues for European and Asian customers by reducing network latency and avoiding timeouts.

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Scalability

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Elasticity

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High availability

Question 9

A company traditionally purchased physical servers and networking equipment every three years, paying the full cost upfront. They are now migrating their workloads to Azure virtual machines. The finance team wants to understand the primary financial benefit of the new cloud model. Which statement best describes this benefit?

Accepted Answer

The company can replace large upfront capital expenditures with variable monthly payments based on actual usage.. Option B is correct because migrating from on-premises physical servers to Azure virtual machines shifts the cost model from Capital Expenditure (CapEx) — paying the full hardware cost upfront every three years — to Operational Expenditure (OpEx), where you pay only for the compute, storage, and network resources you actually consume on a monthly basis. This aligns costs directly with usage, avoiding large upfront investments and enabling better cash flow management.

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The company can stop paying for electricity and cooling because Azure includes those costs in the monthly bill.

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The company will pay a fixed monthly fee for each virtual machine, regardless of whether it is running or stopped.

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The company can reduce its overall IT spending by 50% or more when moving to the cloud.

Question 10

An IT team manages a customer relationship management (CRM) application hosted on a single Azure virtual machine. As the number of users grows, the CPU and memory usage on the VM consistently exceed 90%. The team decides to increase the VM size from Standard_D2s_v3 (2 vCPUs, 8 GB RAM) to Standard_D8s_v3 (8 vCPUs, 32 GB RAM) to handle the increased load. The application is not designed to run on multiple servers simultaneously. This approach represents which type of scaling in the cloud?

Accepted Answer

Vertical scaling. Increasing the VM size from Standard_D2s_v3 to Standard_D8s_v3 adds more vCPUs and RAM to the same virtual machine, which is the definition of vertical scaling (scaling up). This approach is appropriate because the application cannot run on multiple servers simultaneously, so adding resources to the existing single VM is the only viable option to handle the increased load.

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Horizontal scaling

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Diagonal scaling

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Auto-scaling

Question 11

A global software company hosts its SaaS product on Azure. Thousands of different customers' virtual machines and databases run on the same physical servers in Microsoft's data centers, yet each customer can only access their own resources and cannot see or interact with other customers' data. Which cloud computing characteristic does this scenario primarily describe?

Accepted Answer

Resource pooling. Resource pooling is the correct answer because the scenario describes a multi-tenant architecture where Microsoft's Azure data centers use a shared physical infrastructure (servers, storage, network) to serve multiple customers. Each customer's VMs and databases are isolated via hypervisor-level virtualization and network segmentation, ensuring they cannot access each other's data. This pooling of resources to serve many customers, with dynamic assignment and reassignment of physical and virtual resources, is the defining characteristic of resource pooling as per the NIST definition of cloud computing.

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Rapid elasticity

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Measured service

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On-demand self-service

Question 12

A startup runs a web application on Azure virtual machines. The application experiences sudden, short-lived spikes in traffic multiple times a day. The startup configures an autoscale rule that adds two additional VM instances when CPU usage exceeds 75% and removes them when CPU drops below 30%. This approach is designed to match resource consumption closely to demand. Which cloud computing characteristic does this scenario primarily demonstrate?

Accepted Answer

Elasticity. Elasticity is the ability of a cloud system to automatically scale resources up or down based on real-time demand. In this scenario, the autoscale rule dynamically adds two VM instances when CPU exceeds 75% and removes them when CPU drops below 30%, closely matching resource consumption to traffic spikes. This on-demand provisioning and de-provisioning of compute capacity is the defining characteristic of elasticity.

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High Availability

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Fault Tolerance

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Durability

Question 13

A global consulting firm has offices in New York, London, and Tokyo. They deployed a document management system on Azure App Service. Consultants need to access the system from any location worldwide using laptops or smartphones over public Wi-Fi or cellular networks, without needing a VPN connection. After deployment, all consultants can successfully log in and use the application from any internet-connected device. Which characteristic of cloud computing does this scenario best illustrate?

Accepted Answer

Broad network access. This scenario best illustrates broad network access because the document management system is accessible over the internet from any location using laptops or smartphones without requiring a VPN. Broad network access means resources can be accessed via standard network protocols (e.g., HTTPS) from a wide range of devices, including mobile phones and laptops, over public networks like Wi-Fi or cellular. The consultants' ability to log in and use the application from any internet-connected device directly demonstrates this characteristic.

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High availability

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Resource pooling

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Rapid elasticity

Question 14

A company deploys a line-of-business application on an Azure virtual machine. The IT team wants to ensure the application remains secure. According to the shared responsibility model, which of the following security tasks is the sole responsibility of the customer (the company)?

Accepted Answer

Configuring the network security group (NSG) rules to restrict inbound traffic to the virtual machine.. Option B is correct because configuring Network Security Group (NSG) rules to restrict inbound traffic is a customer responsibility under the shared responsibility model. The customer controls the virtual network and VM-level access, including defining allow/deny rules for protocols like TCP/UDP on specific ports. Azure manages the underlying infrastructure, but the customer must secure their own application traffic.

Answer

Protecting the physical servers in the Azure datacenter with video surveillance and access controls.

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Ensuring the hypervisor that isolates virtual machines is free from vulnerabilities.

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Maintaining the security of the Azure Fabric Controller that manages the host servers.

Question 15

A development team lead needs to quickly provision a new Azure virtual machine for a short-term testing project. Instead of submitting a ticket to the IT procurement team and waiting several days for hardware approval and setup, the lead directly signs into the Azure portal, configures the VM settings, and has it running within 15 minutes. The entire process required no human interaction from the cloud provider's staff. Which cloud computing characteristic does this scenario primarily demonstrate?

Accepted Answer

On-demand self-service. The scenario demonstrates on-demand self-service because the development team lead was able to provision and configure an Azure virtual machine directly through the Azure portal without any human interaction from Microsoft's staff. This characteristic allows users to automatically obtain computing resources, such as VM time and storage, as needed without requiring manual approval or provisioning from the cloud provider's IT team.

Answer

Broad network access

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Measured service

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Resource pooling