AZ-900 Describe cloud concepts Practice Test 7 — 15 Questions

Question 1

A retail company runs an e-commerce website on Azure. The website experiences highly unpredictable traffic with occasional sudden spikes (e.g., during flash sales). Outside of sales events, the website has low traffic. The company wants to automatically increase the number of virtual machines during peak demand and automatically reduce them when demand subsides, without any manual intervention. The primary goal is to handle variable demand efficiently while minimizing cost. Which cloud computing characteristic best describes this capability?

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

Accepted Answer

Elasticity. Elasticity is the correct answer because it specifically refers to the ability of a cloud system to automatically provision and de-provision resources (such as virtual machines) in response to real-time demand changes. In this scenario, the e-commerce website needs to scale out during flash sales and scale in during low traffic periods without manual intervention, which is the defining characteristic of elasticity. This capability directly supports the goal of handling variable demand efficiently while minimizing cost, as resources are only consumed when needed.

Answer

High availability

Answer

Fault tolerance

Answer

Scalability

Question 2

A company deploys an Azure SQL Database. The company is billed based on the amount of data stored and the number of transactions per second (DTUs). At the end of each month, the company receives an invoice that itemizes the exact usage and the corresponding charges. Which of the five essential characteristics of cloud computing does this billing model primarily demonstrate?

Accepted Answer

Measured service. The billing model for Azure SQL Database, which itemizes usage based on data stored and transactions per second (DTUs), directly demonstrates the 'Measured service' characteristic. This is because cloud providers meter and charge for resource consumption (storage and DTUs) with pay-per-use billing, providing transparency for both the provider and consumer. The detailed invoice showing exact usage and charges is the hallmark of measured service, where usage is monitored, controlled, and reported.

Answer

On-demand self-service

Answer

Broad network access

Answer

Resource pooling

Question 3

A company is migrating a legacy customer relationship management (CRM) application to Azure infrastructure as a service (IaaS). The application runs on Windows Server and uses a third-party database. The company's IT team will manage the application and database software. However, they want to minimize their operational overhead for tasks that Azure can handle automatically. According to the shared responsibility model, which of the following tasks is the responsibility of Microsoft?

Accepted Answer

Replacing a failed physical hard disk drive in the Azure data center.. In the shared responsibility model, Microsoft is responsible for the 'physical' aspects of the cloud, including the hardware, network, and data center infrastructure. Replacing a failed physical hard disk drive is a physical infrastructure task that falls under Microsoft's responsibility, as the customer has no access to the underlying hardware in an IaaS environment.

Answer

Applying security updates to the CRM application code.

Answer

Configuring firewall rules within the virtual network.

Answer

Installing the latest Windows Server security patches on the virtual machine.

Question 4

A company has a legacy on-premises application that processes sensitive financial data. Due to regulatory requirements, certain data cannot leave the company's on-premises data center. However, the company wants to take advantage of the cloud's scalability for the application's compute-intensive batch processing jobs. The batch jobs need to access the sensitive data but must process it without the data ever being stored in the cloud. The batch jobs will be orchestrated from the cloud. Which cloud deployment model best describes this architecture?

Accepted Answer

Hybrid cloud. This architecture is a hybrid cloud because it combines on-premises infrastructure (where sensitive data resides and must remain) with public cloud resources (for compute-intensive batch processing). The batch jobs are orchestrated from the cloud but access the sensitive data on-premises without storing it in the cloud, which is a classic hybrid deployment pattern. Hybrid cloud enables workload portability and orchestration across private and public environments while meeting data residency and regulatory requirements.

Answer

Public cloud

Answer

Private cloud

Answer

Multi-cloud

Question 5

A startup company is developing a new mobile application. The development team needs to quickly create test environments to validate new features. They can provision virtual machines and databases in Azure within minutes, use them for a few hours, and then delete them when done. This ability to rapidly deploy and decommission resources directly supports which cloud computing benefit?

Accepted Answer

Agility. The scenario describes the ability to rapidly provision and decommission Azure resources like virtual machines and databases in minutes, use them for a few hours, and then delete them. This directly supports cloud agility, which is the cloud computing benefit that enables organizations to quickly adapt to changing requirements by deploying and releasing resources on demand. Agility is about speed and flexibility in resource management, not just scaling or metering.

Answer

Scalability

Answer

Elasticity

Answer

Measured service

Question 6

A company is evaluating moving its on-premises datacenter to Azure. The CFO points out that Microsoft purchases servers, networking equipment, and cooling systems in enormous quantities, enabling them to negotiate lower prices from hardware vendors. The company expects to benefit from these lower hardware costs as it migrates. Which cloud computing benefit does this scenario primarily describe?

Accepted Answer

Economies of scale. The scenario describes how Microsoft's massive purchasing power reduces per-unit costs for hardware like servers and cooling systems, which is the definition of economies of scale. This benefit is passed to customers through lower Azure service prices, not through any operational or architectural feature of the cloud itself.

Answer

Elasticity

Answer

High availability

Answer

Measured service

Question 7

A company runs a mission-critical application on Azure virtual machines. The application is hosted in the East US Azure region. To protect against a regional disaster, the company configures Azure Site Recovery to replicate the VMs to a secondary region (West US). If a disaster occurs in East US, the company can initiate a failover to West US and bring the application back online within minutes using the replicated data. Which cloud computing benefit does this scenario best demonstrate?

Accepted Answer

Disaster recovery and business continuity. Azure Site Recovery provides disaster recovery and business continuity by replicating Azure VMs from the primary region (East US) to a secondary region (West US). In the event of a regional disaster, failover can be initiated to bring the application online within minutes using the replicated data, ensuring minimal downtime and data loss. This directly aligns with the cloud benefit of disaster recovery and business continuity, which focuses on maintaining operations during catastrophic failures.

Answer

Elasticity

Answer

Pay-as-you-go pricing

Answer

Geo-redundancy

Question 8

A company uses Azure to host a web application. The finance team reviews the monthly invoice and notices that the charges are based on the exact number of hours each virtual machine was running, the amount of storage consumed, and the volume of data transferred out of Azure. They did not pay a fixed upfront cost. Which cloud computing characteristic does this billing model best illustrate?

Accepted Answer

Measured service. The billing model described—charging based on exact hours of VM runtime, storage consumed, and data transfer out—directly aligns with the 'measured service' characteristic of cloud computing. This characteristic means cloud providers meter and bill for resource usage at a granular level (e.g., per hour, per GB), with no upfront fixed cost, enabling a pay-as-you-go model. Azure implements this through its usage meters and billing APIs, which track consumption precisely for each resource.

Answer

Rapid elasticity

Answer

Resource pooling

Answer

On-demand self-service

Question 9

A company migrates its on-premises SQL Server database to Azure SQL Database. The company's security team is concerned about who is responsible for applying security updates to the operating system that hosts the database engine. According to the shared responsibility model for cloud computing, who is responsible for patching the operating system of the underlying host?

Accepted Answer

Microsoft (Azure). In the shared responsibility model for Azure SQL Database, Microsoft is responsible for the underlying infrastructure, including the operating system that hosts the database engine. Azure SQL Database is a Platform as a Service (PaaS) offering, where Microsoft manages the host OS, applies security patches, and ensures the physical and virtual environment is secure. The customer is only responsible for data, access management, and database-level configurations.

Answer

The company (customer)

Answer

Both the company and Microsoft share this responsibility

Answer

A third-party managed service provider

Question 10

A company runs a critical transaction processing application on two Azure virtual machines. The infrastructure is designed so that if one virtual machine encounters a hardware failure and stops functioning, the other virtual machine continues to serve traffic without any interruption or loss of service. Which cloud computing characteristic does this design primarily address?

Accepted Answer

Fault tolerance. The design ensures that if one virtual machine fails due to a hardware failure, the other continues serving traffic without any interruption or loss of service. This is the definition of fault tolerance, which eliminates any single point of failure and maintains continuous operation even when a component fails. High availability reduces downtime but may allow brief interruptions during failover, whereas fault tolerance guarantees zero interruption.

Answer

High availability

Answer

Disaster recovery

Answer

Scalability

Question 11

A company runs an e-commerce website on a set of on-premises servers that are fully owned and depreciated. The website experiences predictable traffic surges during seasonal sales. The company plans to migrate to Azure and wants to pay only for the compute and storage resources consumed, with the ability to automatically add virtual machines during sales and remove them afterward. Which characteristic of cloud computing does this scenario best illustrate?

Accepted Answer

Elasticity. Elasticity is the cloud computing characteristic that allows resources to automatically scale out (add virtual machines) during demand spikes like seasonal sales and scale in (remove VMs) when demand drops, aligning with the pay-per-use model. This scenario directly matches elasticity because the company wants to dynamically adjust compute and storage resources in response to predictable traffic surges, paying only for what is consumed.

Answer

High availability

Answer

Fault tolerance

Answer

Disaster recovery

Question 12

A company is evaluating moving their workloads to Azure. They currently operate a small on-premises data center. Their IT manager notes that by using Azure, they will benefit from the fact that Microsoft operates many large data centers globally, which allows them to achieve lower network bandwidth costs and hardware procurement discounts. The company will not have to negotiate separate contracts for power and cooling. Which cloud computing concept does this benefit best illustrate?

Accepted Answer

Economies of scale. The scenario describes how Microsoft's global scale of operations—operating many large data centers—enables lower network bandwidth costs and hardware procurement discounts, and eliminates the need for separate power and cooling contracts. This directly illustrates economies of scale, where the average cost per unit decreases as the scale of operations increases, allowing Microsoft to pass these savings to customers. It is not about technical capabilities like availability, elasticity, or agility, but about the cost advantage derived from massive infrastructure investment.

Answer

High availability

Answer

Elasticity

Answer

Agility

Question 13

A company runs a web application on Azure App Service. During a marketing campaign, the application's traffic surges to five times its normal level. The application is configured to automatically add more instances to handle the increased load and then remove them when demand returns to normal. This ability to dynamically provision and de-provision resources based on real-time demand is a direct example of which cloud computing characteristic?

Accepted Answer

Elasticity. The scenario describes automatically adding and removing App Service instances in response to real-time traffic spikes, which is the definition of elasticity. Elasticity is the ability to dynamically scale resources up or down to match demand, ensuring you only pay for what you use. In Azure, this is implemented via autoscale rules that adjust the instance count based on metrics like CPU or request queue length.

Answer

Scalability

Answer

High availability

Answer

Fault tolerance

Question 14

A company is developing a custom web application that will be deployed to Azure. The development team wants to minimize operational overhead and avoid any responsibility for managing the underlying operating system, runtime, or middleware. They want to focus solely on writing application code and managing data. Which cloud service model should the company use for this application?

Accepted Answer

Platform as a Service (PaaS). Platform as a Service (PaaS) is the correct model because it abstracts the underlying OS, runtime, and middleware, allowing developers to focus solely on writing application code and managing data. Azure App Service is a PaaS offering that provides automatic patching, load balancing, and scaling without any responsibility for the host OS or runtime environment. This directly matches the requirement to minimize operational overhead and avoid managing infrastructure layers.

Answer

Infrastructure as a Service (IaaS)

Answer

Software as a Service (SaaS)

Answer

Functions as a Service (FaaS)

Question 15

A company is migrating its on-premises virtual machines (VMs) to Azure using the Infrastructure as a Service (IaaS) model. The VMs run a custom legacy application that requires specific OS-level configurations. The company's IT team wants to understand which party is responsible for applying operating system security patches after the migration. According to the shared responsibility model, who is responsible for patching the OS of the Azure VMs?

Accepted Answer

The company is responsible for patching the operating system on the virtual machines.. In the shared responsibility model for IaaS, the customer retains control over the operating system, including applying security patches. Microsoft manages the physical host, hypervisor, and Azure infrastructure, but the customer is responsible for OS-level configurations and updates on their virtual machines. This applies to both Windows and Linux VMs, regardless of whether the OS is provided by Azure or the customer.

Answer

Microsoft is fully responsible for applying OS patches to the virtual machines.

Answer

Responsibility is shared equally between Microsoft and the company for OS patching.

Answer

Responsibility depends on whether the VM uses Windows or Linux; Microsoft patches Windows VMs and the company patches Linux VMs.