AZ-900 Describe cloud concepts — 20 Questions

Question 1

A company wants to ensure that its cloud resources are available even if a major disaster occurs in one region. They plan to deploy resources in two different geographic locations. Which cloud computing characteristic does this scenario primarily address?

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

Accepted Answer

C) High availability. High availability (HA) is correct because the scenario explicitly describes deploying resources in two different geographic locations to ensure that the cloud resources remain available even if a major disaster occurs in one region. HA focuses on minimizing downtime by providing redundant resources across locations, including multi-region deployments. Disaster recovery (DR), on the other hand, focuses on restoring services and data after a catastrophic failure, often involving backups and recovery plans, not necessarily continuous availability. Since the goal is to keep resources available before and during the disaster, HA is the primary characteristic addressed.

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A) Scalability

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B) Elasticity

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D) Disaster recovery

Question 2

A company runs several virtual machines on Azure that are hosted on physical servers shared with other customers. The company is concerned that another customer's high workload ('noisy neighbor') could degrade their own application performance. However, Azure's infrastructure ensures that each virtual machine receives a dedicated allotment of CPU and memory resources, and performance remains consistent regardless of the activity of other tenants. Which characteristic of cloud computing does this scenario best illustrate?

Accepted Answer

Resource pooling. Resource pooling is the correct answer because it describes how Azure's multi-tenant architecture allows physical resources (CPU, memory, storage, network) to be shared among multiple customers while ensuring each virtual machine receives a dedicated allocation of resources. This isolation prevents a 'noisy neighbor' scenario from degrading performance, as each VM's resource allotment is guaranteed regardless of other tenants' activity.

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Measured service

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Rapid elasticity

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On-demand self-service

Question 3

A financial services company has an on-premises data center that houses sensitive customer data. Regulatory requirements mandate that this data cannot be stored or processed outside the company's physical premises. However, the company wants to take advantage of cloud computing for compute-intensive risk analysis workloads that process anonymized subsets of the data. The company also needs to maintain a consistent management and security posture across both environments. Which cloud deployment model should the company adopt?

Accepted Answer

Hybrid cloud. Hybrid cloud is correct because it allows the company to keep sensitive customer data on-premises to meet regulatory requirements while leveraging the public cloud for compute-intensive risk analysis on anonymized subsets. This model also enables consistent management and security policies across both environments through unified tools like Azure Arc.

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Public cloud

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Private cloud

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Community cloud

Question 4

A company currently runs its IT operations entirely on-premises. The finance team is evaluating moving to Azure and wants to understand the financial impact. They currently purchase new servers every five years as a large upfront capital expenditure (CapEx). In Azure, they would pay a fixed monthly subscription for virtual machines instead. This shift from a large upfront payment to a smaller monthly operational expense (OpEx) is a direct illustration of which cloud computing benefit?

Accepted Answer

Consumption-based pricing (OpEx model). The shift from a large upfront capital expenditure (CapEx) for on-premises servers to a monthly operational expense (OpEx) for Azure virtual machines directly illustrates the consumption-based pricing model, a key cloud benefit. This model converts capital costs into recurring operational costs, enabling better cash flow management and budget predictability.

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Elasticity

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High availability

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Predictable performance

Question 5

A company runs a batch job every night that takes 4 hours and cannot be interrupted. Which VM pricing model provides the lowest cost for this workload?

Accepted Answer

Pay-as-you-Go Instances. Pay-as-you-go pricing is the most cost-effective for a nightly 4-hour batch job because it charges only for the time the VM runs, without requiring an upfront commitment. Reserved Instances are designed for always-on workloads; using them for only 4 hours per night would waste the paid capacity during idle hours, making Pay-as-you-go cheaper for intermittent usage.

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Spot VMs

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Reserved Instances (1 or 3-year)

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Dedicated Hosts

Question 6

A startup wants to deploy a web application that experiences unpredictable traffic spikes. They need to scale resources automatically without manual intervention. Which benefit of cloud computing directly addresses this requirement?

Accepted Answer

Elasticity. Elasticity is the cloud computing benefit that enables resources to automatically scale out (add instances) during traffic spikes and scale in (remove instances) when demand drops, without manual intervention. This directly matches the startup's need to handle unpredictable traffic patterns by dynamically adjusting compute capacity, typically using services like Azure Virtual Machine Scale Sets or Azure App Service auto-scale rules.

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High availability

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Disaster recovery

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Fault tolerance

Question 7

A retail company runs its e-commerce platform on a public cloud. During a major sale event, they want to ensure that the application remains accessible even if an entire data center fails. Which cloud computing concept does this describe?

Accepted Answer

High availability. High availability ensures that the application remains accessible even if an entire data center fails, typically through redundant infrastructure across multiple availability zones. This is achieved by deploying the application in a load-balanced, multi-AZ configuration that automatically fails over to healthy instances, maintaining uptime despite a complete data center outage.

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Scalability

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Elasticity

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Disaster recovery

Question 8

A financial services company is evaluating a public cloud provider. They are concerned about the shared responsibility model for security. The company must ensure that their customer data is encrypted at rest and in transit. Under the shared responsibility model, which security control is the cloud provider typically responsible for?

Accepted Answer

Physical network security. Under the shared responsibility model, the cloud provider is responsible for the security OF the cloud, which includes physical network security such as protecting the data center perimeter, network infrastructure, and hardware. This is correct because physical security controls (e.g., access badges, surveillance, and network firewalls at the provider's edge) are entirely the provider's domain and cannot be delegated to the customer.

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Encrypting customer data at rest

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Patching virtual machines

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Managing customer access policies

Question 9

A multinational corporation wants to reduce its carbon footprint by shifting workloads to the cloud. They want to understand how using a cloud provider's shared infrastructure contributes to sustainability. Which cloud computing concept is most directly related to this environmental benefit?

Accepted Answer

Resource pooling. Resource pooling is the cloud computing concept most directly related to sustainability because it allows a cloud provider to serve multiple customers from the same shared physical infrastructure. By dynamically allocating and reallocating resources based on demand, the provider maximizes utilization rates, reducing the total number of physical servers and data centers needed. This consolidation directly lowers energy consumption and carbon emissions per workload, which is the core environmental benefit of shifting to the cloud.

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Broad network access

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On-demand self-service

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Rapid elasticity

Question 10

A small business wants to move its accounting software to the cloud to avoid purchasing and maintaining physical servers. Which cloud service model would provide the accounting application as a ready-to-use service over the internet?

Accepted Answer

Software as a Service (SaaS). (SaaS) is correct because the business needs a ready-to-use accounting application delivered over the internet without managing underlying infrastructure. SaaS provides fully functional software accessed via a web browser, where the provider handles all maintenance, updates, and server management, aligning perfectly with the goal of avoiding physical server ownership.

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Infrastructure as a Service (IaaS)

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Platform as a Service (PaaS)

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Function as a Service (FaaS)

Question 11

A hospital is subject to strict data residency laws that require patient data to remain within the country's borders. They are considering using a public cloud provider. Which cloud deployment model would best meet this compliance requirement?

Accepted Answer

Private cloud. A private cloud is dedicated to a single organization, allowing the hospital to deploy and manage infrastructure within its own data center or a colocation facility located within the country's borders. This ensures full control over data storage and processing, directly satisfying data residency laws that prohibit patient data from leaving the country. In contrast, public cloud providers may have data centers in multiple regions, making it harder to guarantee data never crosses borders.

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Public cloud

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Hybrid cloud

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Community cloud

Question 12

A small business wants to run its accounting application without managing the underlying operating systems or hardware. The application is accessed through a web browser. Which cloud service model is being used?

Accepted Answer

Software as a Service (SaaS). (SaaS) because the business uses a web browser to access the accounting application without managing the underlying OS or hardware. SaaS delivers fully functional software over the internet, where the provider handles all infrastructure, platform, and application management, matching the scenario's requirement of zero administrative overhead.

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Infrastructure as a Service (IaaS)

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Platform as a Service (PaaS)

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Functions as a Service (FaaS)

Question 13

A financial services company processes sensitive customer data and must strictly control the physical location of the servers. They want to use cloud computing but with dedicated hardware that is not shared with other customers. Which cloud deployment model should they choose?

Accepted Answer

Private cloud. A private cloud is the correct deployment model because it provides dedicated, single-tenant infrastructure that is not shared with other customers. This ensures that the financial services company can maintain strict physical control over server locations and meet compliance requirements for sensitive customer data, as the hardware is exclusively used by one organization.

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Public cloud

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Hybrid cloud

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Community cloud

Question 14

A company runs a web application that experiences sudden spikes in traffic during promotional events. They want to automatically add more virtual machines during high demand and remove them when traffic subsides, paying only for the resources used. Which cloud computing benefit does this scenario describe?

Accepted Answer

Elasticity. This scenario describes elasticity, which is the ability of a cloud system to automatically provision and de-provision resources (such as virtual machines) in response to real-time demand changes. The key phrase 'automatically add more virtual machines during high demand and remove them when traffic subsides, paying only for the resources used' directly matches the cloud computing benefit of elasticity, where scaling is dynamic and resource usage is metered, ensuring cost efficiency.

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Scalability

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High availability

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Fault tolerance

Question 15

A company is evaluating moving its on-premises applications to the cloud. The IT manager wants to avoid upfront hardware costs and instead pay for resources on a monthly basis based on usage. Which cloud characteristic enables this financial model?

Accepted Answer

Consumption-based pricing. Consumption-based pricing is the cloud characteristic that allows organizations to pay only for the resources they actually use, such as compute hours, storage GBs, or data transfer, without any upfront hardware costs. This model shifts IT spending from a capital expenditure (CapEx) to an operational expenditure (OpEx), aligning costs directly with usage. The IT manager's requirement to avoid upfront costs and pay monthly based on usage is the exact definition of consumption-based pricing.

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Measured service

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Rapid elasticity

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Resource pooling

Question 16

A company is considering moving its IT infrastructure to the cloud. The CFO wants to understand the financial impact: instead of purchasing servers and paying for maintenance, the company will pay a monthly fee based on usage. This shift represents moving from which type of expenditure to which?

Accepted Answer

From capital expenditure (CapEx) to operational expenditure (OpEx). This shift represents moving from capital expenditure (CapEx) to operational expenditure (OpEx). CapEx involves upfront costs for physical assets like servers, which depreciate over time, while OpEx involves ongoing, usage-based payments for cloud services. In Azure, this aligns with the consumption-based model where you pay only for resources consumed (e.g., VM hours, storage GBs), eliminating large initial investments and shifting financial risk to the provider.

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From operational expenditure (OpEx) to capital expenditure (CapEx)

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From direct expenditure to indirect expenditure

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From variable expenditure to fixed expenditure

Question 17

A company wants to increase the number of virtual machines it uses during peak hours and decrease them during off-peak hours without manual intervention. Which characteristic of cloud computing does this represent?

Accepted Answer

Elasticity. Elasticity is the cloud characteristic that allows resources to automatically scale out (increase) during peak demand and scale in (decrease) during off-peak hours without manual intervention. This matches the company's requirement for dynamic, automatic adjustment of virtual machine counts based on workload changes.

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High Availability

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Scalability

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Load Balancing

Question 18

A startup wants to use a cloud-based email service without installing any software on their own computers. They access the service through a web browser and the provider manages all updates and maintenance. Which cloud service model does this represent?

Accepted Answer

Software as a Service (SaaS). This scenario describes Software as a Service (SaaS) because the startup is using a fully managed cloud-based email application accessed via a web browser, with no local installation required. The provider handles all updates, maintenance, and infrastructure, which is the defining characteristic of SaaS. Examples include Microsoft 365 or Google Workspace, where the consumer only uses the software without managing the underlying platform or infrastructure.

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Infrastructure as a Service (IaaS)

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Platform as a Service (PaaS)

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Anything as a Service (XaaS)

Question 19

A bank needs to keep some sensitive customer data on-premises due to regulatory requirements, but wants to use cloud services for less sensitive workloads. Which cloud deployment model should they adopt?

Accepted Answer

Hybrid cloud. A hybrid cloud model combines on-premises infrastructure (private cloud) with public cloud services, allowing the bank to keep sensitive customer data on-premises to meet regulatory requirements while using the public cloud for less sensitive workloads. This approach provides a unified management plane and secure connectivity (e.g., VPN or Azure ExpressRoute) between the two environments, ensuring compliance and flexibility.

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Public cloud

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Private cloud

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Community cloud

Question 20

A company is moving from an on-premises data center to Azure. Instead of paying a large upfront cost for servers, they will pay a monthly subscription fee based on usage. This represents a shift from which type of expenditure to which?

Accepted Answer

Capital expenditure to Operational expenditure. This scenario describes a shift from Capital Expenditure (CapEx) to Operational Expenditure (OpEx). CapEx involves upfront, long-term investments in physical assets like servers, while OpEx is a pay-as-you-go model where costs are incurred based on actual usage. Azure's subscription model eliminates the need for large initial capital outlays, aligning costs with consumption.

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Operational expenditure to Capital expenditure

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Direct cost to Indirect cost

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Fixed cost to Variable cost