AZ-900 Exam Questions and Answers

Elasticity

Elasticity is the cloud characteristic that allows a web application to automatically increase or decrease compute, storage, or networking resources in response to live traffic. Azure autoscale, often paired with Virtual Machine Scale Sets or App Service, uses metric thresholds such as CPU utilization or request queue length to add or remove instances on demand. This directly addresses unpredictable spikes and troughs, making it the correct answer.

High availability

High availability is a design principle that minimizes application downtime by eliminating single points of failure and enabling automatic failover when a component fails. This is achieved through redundancy (multiple instances, Azure Availability Zones, or Availability Sets), health probes, and load balancers that reroute traffic to healthy replicas. In the e-commerce scenario, HA ensures the platform remains reachable and functional during a component failure, directly addressing the stated requirement to keep services running.

Physical network security

Physical network security is the provider's responsibility because the cloud provider operates and controls the physical data center infrastructure. This includes securing the facility, cabling, switches, routers, and firewalls against physical tampering, environmental threats, and unauthorized access. The customer has no visibility or control over these physical layers, so under the shared responsibility model this falls entirely on Microsoft.

Resource pooling

Resource pooling is the cloud characteristic that directly underpins sustainability: providers virtualize and share physical infrastructure across many tenants, dramatically reducing idle capacity and per-workload energy overhead. By consolidating workloads into hyperscale data centers optimized for Power Usage Effectiveness (PUE), resource pooling lowers total electricity consumption and carbon emissions relative to each customer operating dedicated hardware.

Software as a Service (SaaS)

SaaS is a cloud service model that delivers complete, ready-to-use applications over the internet, typically on a subscription basis. For accounting, a SaaS provider like QuickBooks Online or Microsoft Dynamics 365 supplies the fully functional software, including the application, data storage, and underlying infrastructure, eliminating the need to purchase perpetual licenses or install software on local machines. The customer just configures the service and begins using it.

Private cloud

A private cloud is a cloud computing environment dedicated exclusively to a single organization, either on-premises or hosted by a third-party provider with isolated infrastructure. This gives the hospital direct control over the physical location of servers, storage, and networks, allowing it to ensure all data remains within a specific geographic boundary as required by data residency laws. Moreover, private cloud can be configured with strict access policies, encryption, and audit logs to meet healthcare compliance standards like HIPAA, making it the most reliable choice for strict data residency.

Azure Kubernetes Service (AKS)

Azure Kubernetes Service (AKS) is the correct choice because it provides a fully managed Kubernetes control plane, enabling containerized microservices to be deployed, scaled, and updated independently. With native support for horizontal pod autoscaling, service discovery, and rolling updates, AKS directly addresses the requirement for independent scaling and deployment of each microservice component, without the operational overhead of managing the control plane yourself.

Blob Storage - Cool tier

Azure Blob Storage Cool tier is optimized for data that is infrequently accessed but must be available immediately on demand. It offers significantly lower storage costs than the Hot tier while maintaining millisecond access latency, making it ideal for video files that are viewed only occasionally but require instant playback. Lifecycle management policies can automatically transition blobs to Cool tier after a set period of inactivity, providing a cost-effective balance between performance and price.

Blob Storage - Archive tier

The Archive tier in Azure Blob Storage delivers the absolute lowest storage cost of any Azure storage option, designed for data that is rarely accessed and must be retained long-term, such as compliance archives. However, blobs in Archive are offline and require rehydration to an online tier before reading, with retrieval latency ranging from minutes to up to 15 hours. This makes it perfect for media assets that must be preserved for regulatory purposes but are almost never accessed, as long as you can tolerate delay when retrieval is finally needed.

Azure Functions in Premium plan with VNet integration

Azure Functions Premium plan supports VNet integration, enabling your function app to route outbound and inbound calls to and from resources in a virtual network. With a site-to-site VPN or ExpressRoute, you can securely connect that VNet to your on-premises SQL Server, keeping database traffic off the public internet. This preserves the event-driven serverless model while providing private, predictable network access.

Azure App Service and Azure SQL Database

Azure App Service is a fully managed PaaS offering for web applications that provides automatic scaling, load balancing, and built-in DevOps capabilities without managing VMs. Azure SQL Database is a managed relational database with high availability, automated backups, and a compatibility level for typical transactional SQL workloads. Together they form a standard multi-tier stack where the web tier handles HTTP requests and the data tier stores structured data with low-latency access.

Availability Zones

Availability Zones are physically separate datacenters within an Azure region, each with independent power, cooling, and networking. By placing VMs across multiple zones, you ensure that if an entire datacenter fails, the remaining zones continue to serve traffic, providing true datacenter-level redundancy. This architecture supports an SLA of up to 99.99% for VMs deployed across zones, making it the correct choice for a mission-critical application that must remain available during a facility outage.

Scale out the App Service plan by increasing the instance count.

Scaling out increases the number of VM instances running the App Service plan, allowing Azure's built-in load balancer to distribute incoming requests across all instances. For a predictable doubling of traffic, adding instances provides immediate additional compute capacity and is more cost-effective than scaling up, because you pay per-second for these standard-tier instances and can later scale back in. This manual operation takes effect within seconds to minutes, directly addressing the expected spike now.

Azure Policy

Azure Policy is the correct choice because it can be assigned at management group or subscription scope to enforce resource rules—such as allowed VM SKUs or required tags—across all department subscriptions. Policy definitions use effects like Deny, Audit, or Append, and every existing or newly created resource is continuously evaluated for compliance. A built-in compliance dashboard reports which resources are compliant or non-compliant, giving the centralized governance and reporting the departments require.

Azure Monitor

Azure Monitor is the correct service because it captures and retains the Activity Log, which records control-plane events such as virtual machine deallocation. By creating an Activity Log alert rule, you can define a condition that fires when the 'Deallocate Virtual Machine' operation occurs, sending notifications via action groups to email, SMS, or webhook. This makes Azure Monitor the go-to for real-time, resource-level operational alerts.

Azure Cost Management

Azure Cost Management is the native cloud financial management service for tracking, analyzing, and optimizing spend across Azure subscriptions. It provides a centralized view of costs, supports budget creation with alert thresholds, and includes cost analysis tools to identify spending trends and anomalies. As the umbrella service, it is the correct answer for tracking and optimizing costs.

Management groups

Management groups support hierarchical organization of Azure subscriptions, enabling centralized governance, policy assignment, and access control across a global enterprise. They can nest subscriptions under a common structure, allowing consistent RBAC and compliance at scale. This makes them the appropriate mechanism for organizing resources by business unit, region, or other top-level groupings.

Tags

Tags are key-value pairs that can be assigned to resources, resource groups, or subscriptions to categorize them according to business units, environments, cost centers, or owners. They provide a straightforward way to organize metadata for cost allocation, reporting, and operational filtering, but they do not affect governance or access. Tags are a complementary organizational tool, often used alongside management groups for finer-grained labeling.

Azure Policy

Azure Policy is the correct answer because it is the native Azure governance service that evaluates resource creation and update requests in real time against rule definitions. Policies can enforce tagging by using effects such as 'deny' (blocking resource creation if required tags are missing), 'append' (automatically adding a tag with a default value), or 'audit' (logging non-compliant resources). For example, the built-in policy 'Require a tag and its value on resources' ensures every new resource is created with the specified tag, and you can assign it at subscription or management group scope to make the enforcement consistent across all new resources.

Azure Cost Management + Billing budgets

Azure Cost Management + Billing budgets are purpose-built to track spending against defined monetary thresholds at subscription, resource group, or management group scope. You can configure budget amounts, actual and forecasted cost threshold percentages, and trigger email alerts or automation via action groups when spending approaches or exceeds those levels. Because the service reads Azure billing and meter data, it directly fulfills the requirement to alert on subscription cost limits, unlike the general governance and telemetry tools in the other choices.