AZ-900 Describe cloud concepts Practice Test 16 — 15 Questions

Question 1

What is the primary advantage of deploying VMs across multiple Azure Availability Zones instead of a single Availability Set?

Accepted Answer

Protection against datacenter-level failures with a higher SLA (99.99% vs. 99.95%). Azure Availability Zones are physically separate datacenters within an Azure region, each with independent power, cooling, and networking. Deploying VMs across multiple zones protects against a complete datacenter failure, enabling a 99.99% VM-to-VM connectivity SLA. In contrast, an Availability Set protects against hardware failures within a single datacenter (e.g., rack or update domain failures) and offers a 99.95% SLA.

Answer

VMs in different Availability Zones are always cheaper than Availability Sets

Answer

VMs automatically scale in response to demand when placed in Availability Zones

Answer

Availability Zones reduce network latency between VM instances

Question 2

Which of the following best describes the 'shared responsibility' for operating system updates under the IaaS model?

Accepted Answer

The customer is responsible for patching the guest OS in IaaS VMs. Under the Infrastructure as a Service (IaaS) model, the cloud provider is responsible for the physical infrastructure and the hypervisor, but the customer retains control over the guest operating system running inside the virtual machine. Therefore, the customer is responsible for patching and updating the guest OS, including applying security updates and managing configuration. This aligns with the shared responsibility model where the customer manages anything they deploy on top of the abstracted infrastructure.

Answer

The cloud provider is responsible for patching the OS in IaaS VMs

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Both customer and provider share equal responsibility for OS patches in IaaS

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OS patching is not required in cloud environments as Azure handles this automatically

Question 3

What is the role of a cloud provider's physical datacenter security in the shared responsibility model?

Accepted Answer

Physical security is entirely the cloud provider's responsibility. In the shared responsibility model, physical security of the datacenter—including access controls, surveillance, and environmental controls—is always the sole responsibility of the cloud provider (e.g., Microsoft Azure). The customer never manages or is responsible for the physical infrastructure, regardless of the service model (IaaS, PaaS, SaaS). This is because the customer has no physical access to the datacenter and cannot implement or control physical security measures.

Answer

Both the cloud provider and customer share responsibility for physical security

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Customers are responsible for physical security when using IaaS

Answer

Physical security responsibility depends on the customer's support plan level

Question 4

A startup has unpredictable traffic — sometimes thousands of users, sometimes almost none. Which pricing model best fits their needs?

Accepted Answer

Consumption-based (pay-as-you-go) pricing. Consumption-based (pay-as-you-go) pricing is ideal for unpredictable workloads because it charges only for the resources actually used, with no upfront commitment. This model scales automatically with demand, so the startup pays for compute and storage only when traffic spikes occur, and incurs minimal cost during idle periods. It aligns perfectly with the elastic nature of cloud computing, where resources can be provisioned and deprovisioned dynamically.

Answer

Reserved Instances with a 1-year commitment

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Dedicated Hosts with annual contracts

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Fixed monthly flat-rate pricing

Question 5

Which Azure cloud benefit means organizations don't need to predict future resource needs exactly when planning infrastructure?

Accepted Answer

Stop guessing capacity requirements. The 'Stop guessing capacity requirements' benefit, often referred to as 'Capacity Planning' in the Azure Well-Architected Framework, directly addresses the challenge of over-provisioning or under-provisioning infrastructure. Azure's elastic scaling model allows organizations to provision resources on demand and pay only for what they use, eliminating the need to predict future workloads precisely. This is a core advantage of the consumption-based model in cloud computing, where resources can be scaled up or down automatically based on real-time metrics.

Answer

Economies of scale

Answer

Increased speed and agility

Answer

Go global in minutes

Question 6

Which statement accurately describes the consumption-based pricing model for Azure services?

Accepted Answer

You pay only for the cloud resources you consume, with no upfront costs or wasted capacity. The consumption-based pricing model in Azure means you pay only for the resources you actually use, such as compute hours, storage GB, or data transfer, with no upfront costs or commitments. This model provides flexibility and cost efficiency because you can scale resources up or down based on demand and only incur charges for what you consume. It is a core principle of cloud computing that aligns costs directly with usage, enabling organizations to avoid over-provisioning and reduce waste.

Answer

You pay a fixed monthly fee regardless of how many resources you use

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You must purchase at least 12 months of capacity regardless of usage

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You pay based on the performance level of the service, not actual usage

Question 7

An organization needs to meet GDPR data residency requirements ensuring personal data of EU residents is stored only within the EU. How does Azure support this?

Accepted Answer

Azure provides EU regions and contractual commitments enabling customers to keep EU data within EU boundaries. Azure supports GDPR data residency by offering data center regions within the EU (e.g., West Europe, North Europe, France Central) and including contractual commitments in the Microsoft Online Services Terms that guarantee customer data remains stored in the chosen EU region. Customers must explicitly select these regions during resource deployment and can use Azure Policy to enforce region restrictions, but the core support comes from Azure's physical infrastructure and legal agreements, not automatic enforcement.

Answer

Azure automatically stores all EU customer data in EU regions without configuration

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Azure cannot support GDPR data residency as it's a US company

Answer

Data residency is automatically enforced by Azure Policy without customer configuration

Question 8

What is a key advantage of using Azure Availability Zones over a single data center deployment?

Accepted Answer

Protection against single data center failures with a 99.99% SLA. Azure Availability Zones are physically separate data centers within an Azure region, each with independent power, cooling, and networking. By deploying resources across multiple zones, you protect your application from a single data center failure, and Azure guarantees 99.99% VM uptime SLA when VMs are deployed across two or more zones. This is a key advantage over a single data center deployment, which would have no such cross-zone redundancy.

Answer

Resources deployed across Availability Zones are cheaper than single-zone deployment

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Resources are automatically replicated to a secondary Azure region

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Availability Zones eliminate the need for load balancing

Question 9

Which cloud characteristic ensures data remains accessible and readable even when stored for long periods?

Accepted Answer

Durability. Durability is the cloud characteristic that guarantees data remains intact and readable over extended periods, even in the face of hardware failures or bit rot. Cloud providers achieve this through data replication (e.g., Azure Storage's Locally Redundant Storage (LRS) or Geo-Redundant Storage (GRS)) and erasure coding, ensuring that stored objects survive individual disk or node failures. This is distinct from availability, which focuses on uptime and access, not long-term data integrity.

Answer

Scalability

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Availability

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Performance

Question 10

A company decides to move its email to Microsoft 365. What cloud service model is this an example of?

Accepted Answer

SaaS. Moving email to Microsoft 365 is an example of Software as a Service (SaaS) because Microsoft provides the entire email application (Exchange Online) as a fully managed service. The customer accesses the software via a web browser or email client without managing the underlying infrastructure, operating system, or middleware.

Answer

IaaS

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PaaS

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On-premises

Question 11

What is a key difference between vertical scaling and the benefit of cloud elasticity?

Accepted Answer

Vertical scaling resizes one resource while elasticity adds/removes instances automatically without downtime. Vertical scaling (scaling up) increases the capacity of a single resource, such as adding more RAM or CPU to a virtual machine, but it typically requires downtime to apply the changes. Cloud elasticity, on the other hand, automatically adds or removes instances (horizontal scaling) based on demand, often without downtime, enabling the system to handle variable workloads seamlessly. Option B correctly captures this distinction by contrasting the resizing of one resource with the automated, no-downtime addition or removal of instances.

Answer

Vertical scaling works faster than horizontal scaling

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Vertical scaling is more cost-effective than elasticity for all workloads

Answer

Both vertical and horizontal scaling require manual intervention in cloud environments

Question 12

In the context of cloud computing, what does 'going global in minutes' mean?

Accepted Answer

Deploying applications to multiple worldwide regions rapidly with minimal effort. 'going global in minutes' refers to the ability to deploy applications and services across multiple Azure regions worldwide with minimal effort and rapid provisioning. Azure's global infrastructure, combined with tools like Azure Resource Manager and Traffic Manager, allows you to replicate resources across regions in minutes, enabling low-latency access and disaster recovery without physical hardware shipping.

Answer

Cloud providers can physically ship servers to any country within minutes

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Users anywhere in the world can access cloud applications at zero latency

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Cloud providers can guarantee 100% uptime globally

Question 13

Which of the following correctly describes Azure's approach to pricing for data transfer?

Accepted Answer

Inbound data to Azure is free; outbound data transfer incurs charges. Azure charges for outbound data transfer (egress) from Azure data centers to the internet or other regions, while inbound data transfer (ingress) into Azure is free. This pricing model encourages customers to move data into Azure without upfront cost, but charges apply when data leaves Azure's network, reflecting the bandwidth costs incurred by Microsoft.

Answer

All data transfer (inbound and outbound) is charged at the same rate

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Data transfer is entirely free within Azure regardless of direction or region

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Data transfer is charged based on the speed of the transfer, not the amount

Question 14

What benefit does Azure provide that specifically helps companies maintain business continuity when their primary location is unavailable?

Accepted Answer

Geo-redundancy and disaster recovery capabilities. Azure's geo-redundancy and disaster recovery capabilities, such as Azure Site Recovery and geo-redundant storage (GRS), replicate workloads and data across paired Azure regions. This ensures that if a primary location fails due to an outage or disaster, services can failover to a secondary region, maintaining business continuity with minimal downtime and data loss.

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Economies of scale reducing operational costs

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Automatic performance optimization for all applications

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Unified billing for all cloud services

Question 15

What is the difference between 'high availability' and 'fault tolerance' in cloud computing?

Accepted Answer

High availability minimizes downtime during failures; fault tolerance aims for zero interruption despite failures. High availability (HA) focuses on minimizing downtime by using redundant components and failover mechanisms, typically achieving uptime of 99.99% or higher, but it may allow brief interruptions during failover. Fault tolerance, in contrast, is designed to operate without any interruption at all, often through active-active configurations or redundant hardware that masks failures completely. Option B correctly captures this distinction: HA reduces downtime, while fault tolerance aims for zero interruption.

Answer

High availability and fault tolerance are identical concepts

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High availability requires multiple regions; fault tolerance requires only one region

Answer

Fault tolerance is only for databases; high availability is for compute