MS-900 Describe cloud concepts — 15 Questions

Question 1

A company is evaluating moving its on-premises infrastructure to a cloud environment. They want a service that provides virtual machines, storage, and networking capabilities while retaining full control over the operating system and applications. Which cloud service model best meets this requirement?

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

Accepted Answer

Infrastructure as a Service (IaaS). Infrastructure as a Service (IaaS) provides virtualized computing resources, including virtual machines, storage, and networking, over the internet. The customer retains full administrative control over the operating system, applications, and middleware, while the cloud provider manages the underlying physical hardware. This matches the requirement for full OS and application control.

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Software as a Service (SaaS)

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Platform as a Service (PaaS)

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Private Cloud

Question 2

Which characteristic of cloud computing allows a user to provision resources automatically without requiring human interaction with the service provider?

Accepted Answer

On-demand self-service. On-demand self-service is a fundamental characteristic of cloud computing defined by NIST (SP 800-145) that allows a user to unilaterally provision computing capabilities, such as server time and network storage, as needed automatically without requiring human interaction with each service provider. This is typically implemented through a web portal or API (e.g., AWS Console, Azure Portal, or RESTful APIs) that enables instant resource creation and configuration.

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Rapid elasticity

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Resource pooling

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Measured service

Question 3

A company runs a critical application on-premises but wants to extend capacity to the cloud during peak demand without purchasing additional hardware. Which cloud deployment model best describes this strategy?

Accepted Answer

Hybrid cloud. A hybrid cloud model combines on-premises infrastructure (private cloud) with public cloud resources, enabling a company to 'burst' into the public cloud during peak demand without purchasing additional hardware. This strategy, often called cloud bursting, allows the critical application to run locally under normal conditions and seamlessly extend capacity to a public cloud provider like Azure during spikes.

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Public cloud

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Private cloud

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Multi-cloud

Question 4

An e-commerce application runs in the cloud and automatically adjusts the number of virtual machines based on real-time traffic. When traffic spikes, more VMs are added; when traffic drops, VMs are removed. Which cloud computing characteristic does this behavior exemplify?

Accepted Answer

Rapid elasticity. Rapid elasticity is the cloud characteristic that enables resources to scale out (add VMs) and scale in (remove VMs) automatically in response to real-time demand. In this e-commerce scenario, the application adjusts VM count based on traffic spikes and drops, which directly matches the definition of rapid elasticity as defined by NIST SP 800-145.

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Measured service

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Resource pooling

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On-demand self-service

Question 5

A company runs a legacy application that requires a fixed amount of dedicated hardware resources for compliance reasons. However, they want to benefit from cloud-based backup and disaster recovery to reduce on-premises hardware costs. Which cloud deployment model best aligns with this requirement?

Accepted Answer

Hybrid cloud. Hybrid cloud is correct because it allows the company to keep the legacy application on dedicated on-premises hardware for compliance, while leveraging cloud-based backup and disaster recovery services (e.g., Azure Backup and Azure Site Recovery) to reduce on-premises hardware costs. This model combines private cloud (or on-premises infrastructure) with public cloud resources, enabling data replication and failover to the cloud without migrating the application itself.

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Public cloud

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Private cloud

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Community cloud

Question 6

Which cloud deployment model provides the highest level of control over resources and infrastructure?

Accepted Answer

Private cloud. The private cloud deployment model provides the highest level of control over resources and infrastructure because it is dedicated to a single organization, allowing full customization of hardware, networking, and security policies. Unlike public or hybrid models, the organization retains exclusive administrative access and can enforce strict compliance requirements without sharing underlying physical resources with other tenants.

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Public cloud

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Hybrid cloud

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Community cloud

Question 7

A company migrates its database to Azure SQL Database (PaaS). According to the shared responsibility model, which of the following is the customer's responsibility?

Accepted Answer

Managing user access and authentication. In the shared responsibility model for Azure SQL Database (PaaS), the customer is responsible for managing user access and authentication because the customer controls who can connect to the database and what permissions they have. Microsoft manages the underlying infrastructure, including the operating system, physical hardware, and virtualization layer, while the customer must secure data access through Azure Active Directory or SQL authentication, configure firewall rules, and manage logins and users.

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Patching the operating system of the database server

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Maintaining the physical infrastructure

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Managing the virtualization layer

Question 8

A company migrates its database to a cloud service where the provider manages the database engine, patching, backups, and replication. The customer only manages the data and schema. Which cloud service model is this?

Accepted Answer

Platform as a Service (PaaS). Platform as a Service (PaaS) provides a managed hosting environment where the cloud provider handles the underlying infrastructure, including the database engine, operating system, patching, backups, and replication. The customer is responsible only for managing the data and schema, which aligns directly with the scenario described.

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Infrastructure as a Service (IaaS)

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Software as a Service (SaaS)

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On-premises

Question 9

A company wants to deploy a cloud solution where they have the maximum control over the operating system, installed software, and security configurations, but they do not want to manage physical servers or data center facilities. Which cloud service model best meets this requirement?

Accepted Answer

Infrastructure as a Service (IaaS). Infrastructure as a Service (IaaS) provides virtualized computing resources over the internet, giving the customer full administrative control over the operating system, installed software, and security configurations (e.g., firewall rules, patch management) while the cloud provider manages the physical servers, storage, and networking hardware. This model aligns with the requirement for maximum control without managing physical infrastructure.

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Platform as a Service (PaaS)

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Software as a Service (SaaS)

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Hybrid cloud

Question 10

Which cloud deployment model exclusively uses resources that are owned and managed by a single organization, and is often chosen for its high level of control and compliance?

Accepted Answer

Private cloud. The private cloud deployment model is correct because it is defined as a cloud infrastructure that is provisioned for exclusive use by a single organization. This model provides the highest level of control over data, security, and compliance, as the organization owns and manages the underlying hardware and software, often within its own data center or via a dedicated hosted environment.

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Public cloud

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Hybrid cloud

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Community cloud

Question 11

A company wants to use a cloud service that provides ready-to-use business applications such as email, collaboration, and customer relationship management without managing the underlying infrastructure. Which cloud service model is this?

Accepted Answer

Software as a Service (SaaS). (SaaS) is correct because Software as a Service delivers ready-to-use business applications like Microsoft 365 (Exchange Online for email, Teams for collaboration, Dynamics 365 for CRM) over the internet, with the provider managing all underlying infrastructure, including servers, storage, and networking. The customer simply accesses the software via a web browser or client app without any responsibility for patching, scaling, or hardware maintenance.

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Infrastructure as a Service (IaaS)

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Platform as a Service (PaaS)

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Private cloud

Question 12

A financial services company uses a public cloud provider for its development and testing environments, but keeps its production data and applications on-premises due to strict regulatory requirements. Which cloud deployment model is the company using?

Accepted Answer

Hybrid cloud. The company uses a hybrid cloud model because it combines on-premises infrastructure (private cloud) for production workloads with a public cloud provider for development and testing. This allows the organization to meet strict regulatory requirements for data residency and security while leveraging the scalability and cost benefits of the public cloud for non-sensitive workloads.

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Public cloud

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Private cloud

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Community cloud

Question 13

A development team wants to build a custom web application. They choose a cloud service that provides the runtime environment, operating system, and middleware, but the team is responsible for writing and deploying their own code. The provider automatically applies patches to the underlying infrastructure. Which cloud service model best describes this approach?

Accepted Answer

Platform as a Service (PaaS). Platform as a Service (PaaS) provides the runtime environment, operating system, and middleware, allowing developers to focus on writing and deploying their own code while the cloud provider manages the underlying infrastructure, including automatic patching. This model abstracts the hardware and OS layer, giving the team full control over application code but not the platform stack.

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Infrastructure as a Service (IaaS)

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Software as a Service (SaaS)

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Function as a Service (FaaS)

Question 14

A company plans to migrate its on-premises workloads to the cloud. They will use Virtual Machines (VMs) for their legacy applications and a serverless computing service for new microservices. The cloud provider will manage the physical hardware, but the company is responsible for patching the operating system of the VMs. Which two cloud service models are being used?

Accepted Answer

IaaS and PaaS. The company uses Virtual Machines (VMs) for legacy applications, where it manages the OS patching while the cloud provider handles the physical hardware — this is Infrastructure as a Service (IaaS). For new microservices, it uses a serverless computing service, which is a form of Platform as a Service (PaaS) where the provider manages the runtime and scaling, and the company only deploys code. Therefore, the two models are IaaS and PaaS, making option A correct. Option D (IaaS only) is incorrect because it ignores the PaaS component introduced by the serverless service.

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IaaS and SaaS

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PaaS and SaaS

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IaaS only

Question 15

A development team wants to deploy a custom web application. They choose a cloud service that provides the operating system, web server, and database management system. The team is responsible only for uploading and managing their application code. Which cloud service model does this represent?

Accepted Answer

Platform as a Service (PaaS). This scenario describes Platform as a Service (PaaS) because the cloud provider manages the underlying infrastructure—operating system, web server, and database management system—while the development team is responsible only for deploying and managing their custom application code. PaaS abstracts the platform layer, allowing developers to focus on code without worrying about OS patches, web server configuration, or database administration.

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Infrastructure as a Service (IaaS)

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Software as a Service (SaaS)

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Function as a Service (FaaS)