Fundamental
Prepare and test your skills
Fundamental
Prepare and test your skills
Azure Functions for Event-Driven Image Processing
Free sample question, answered and explained below. The AZ-900 Microsoft Azure Fundamentals Exam practice bank has 688 more like it. Try 10 free: instant score, no account.
A retail company wants to automatically process and resize product images whenever photographers upload them to Azure Storage. Image uploads happen sporadically throughout the day, with periods of zero activity followed by sudden bursts.
The company has the following requirements:
- The solution must execute custom code only when a new file upload event occurs.
- Compute resources must automatically scale to handle variable traffic without manual intervention.
- Costs must be incurred only when code is actively executing, avoiding charges for idle time.
- The team wants to eliminate server management, OS patching, and infrastructure maintenance.
Which Azure compute service best meets these requirements?
Explanations
Azure Virtual Machine Scale Sets
Azure Virtual Machine Scale Sets
What Azure Virtual Machine Scale Sets Are
Azure Virtual Machine Scale Sets (VMSS) allow administrators to create and manage a group of identical, load-balanced IaaS virtual machines that can automatically increase or decrease instance counts based on demand or scheduled metrics.
Why It Doesn't Meet the Requirement
- Infrastructure Overhead: VMSS is an IaaS compute model where the customer is still responsible for configuring OS images, applying software updates, and managing runtime dependencies.
- Slower Scaling Latency: Provisioning and booting full virtual machine instances takes minutes, making it poorly suited for immediate, event-driven image processing tasks.
- Ongoing Compute Costs: Maintaining baseline VM instances incurs steady infrastructure charges even when no uploads occur.
Key Characteristics and Limitations
- Provides automated scaling of homogeneous VM instances across availability zones.
- Requires configuration of scaling rules (e.g., CPU or memory threshold metrics).
- Does not offer native, instantaneous trigger-based serverless execution for discrete file upload events.
This Answer Would Be Correct If
The organization needed to deploy and scale large-scale, enterprise IaaS workloads across identical virtual machines with full network and OS level controls.
Azure Virtual Machines
Azure Virtual Machines
What Azure Virtual Machines Are
Azure Virtual Machines (VMs) represent an Infrastructure as a Service (IaaS) offering that delivers customizable, on-demand compute instances with full administrative control over the guest operating system and installed software stack.
Why It Doesn't Meet the Requirement
- Continuous Billing During Idle Time: Azure VMs incur compute charges 24/7 as long as they are running, regardless of whether any image processing code is actively executing.
- High Management Overhead: The administration team remains responsible for operating system patching, security configurations, antivirus updates, and server scaling logic.
- No Native Event-Driven Scaling: An individual VM does not automatically scale instances up and down to zero based on event triggers like file uploads without complex custom orchestration.
Key Characteristics and Limitations
- Provides full root/administrator access to the underlying OS.
- Requires manual configuration for auto-scaling, load balancing, and fault tolerance.
- Classified as IaaS, requiring substantial operational overhead compared to serverless architectures.
This Answer Would Be Correct If
The workload required deep operating system customization, legacy software with specific OS registry dependencies, or persistent long-running processes requiring uninterrupted dedicated compute capacity.
Azure App Service (Dedicated Plan)
Azure App Service (Dedicated Plan)
What Azure App Service Is
Azure App Service is a Platform as a Service (PaaS) environment designed for hosting web applications, RESTful APIs, and mobile backends on managed infrastructure without requiring direct OS management.
Why It Doesn't Meet the Requirement
- Fixed Plan Costs: In a dedicated App Service plan, customers pay for allocated virtual machine instances continuously on an hourly basis, even when no requests or background processing jobs are occurring.
- Does Not Scale to Zero: Dedicated App Service plans maintain pre-provisioned compute instances running at all times rather than scaling to zero during idle periods.
- Suboptimal for Intermittent Event Triggers: While App Service can run WebJobs, it is architected primarily for steady-state web traffic rather than instantaneous, lightweight event processing that charges purely per execution.
Key Characteristics and Limitations
- Provides managed web hosting with built-in SSL, custom domains, and deployment slots.
- Uses dedicated compute resources reserved specifically for your application instances.
- Billed continuously according to the selected App Service plan pricing tier (e.g., Basic, Standard, Premium).
This Answer Would Be Correct If
The scenario involved hosting a continuous web portal or standard HTTP website requiring persistent availability and predictable baseline monthly hosting costs.
Azure Functions
Azure Functions
What Azure Functions Is
Azure Functions is a serverless, event-driven compute service that enables developers to run code in response to various platform events and triggers without having to explicitly provision, manage, or maintain underlying virtual machines or infrastructure.
How It Meets the Requirements
- Event-Driven Execution: Azure Functions natively integrates with triggers such as Azure Blob Storage events, running code automatically whenever a file is uploaded or modified.
- Automatic Dynamic Scaling: When hosted on a serverless Consumption plan, Azure Functions automatically allocates new compute instances to process bursts of incoming events and scales down to zero when traffic stops.
- Execution-Only Billing: With serverless hosting, billing is calculated strictly based on execution count, execution duration, and memory consumption. There is no cost incurred during idle periods.
- Zero Infrastructure Overhead: The cloud platform manages the operating system, runtime environment, high availability, and security patching, freeing developers to focus purely on business logic.
Key Advantages and Capabilities
- Broad Language Support: Allows code development in C#, Python, JavaScript, TypeScript, Java, and PowerShell.
- Rich Trigger and Binding Ecosystem: Seamlessly integrates with services like Azure Cosmos DB, Azure Event Grid, Azure Service Bus, and Azure Queue Storage.
- Ideal for Intermittent Workloads: Perfectly suited for background data processing, webhooks, lightweight APIs, and microservices.
Why This Is Optimal
Compared to hosting virtual machines or running dedicated web app plans, Azure Functions provides a true serverless architecture that minimizes operational overhead and optimizes costs for variable, event-triggered workloads.
Try 10 interactive questions like this one, free
Answer them yourself and get your score the moment you finish. No account needed.
Full access includes
- 688 practice questions across all 3 exam domains
- Every answer explained: why it is right, and why the others are not
- Scout, an AI tutor that answers your follow-up questions
- Readiness tracking by domain, so you know when to book the exam
Related questions
Keep the momentum going with these hand-picked practice scenarios
FundamentalAZ-900 Microsoft Azure Fundamentals Exam
Azure Functions
Compare compute types, including containers, virtual machines, and functions
FundamentalAZ-900 Microsoft Azure Fundamentals Exam
Azure Functions vs Virtual Machines vs Containers
Compare compute types, including containers, virtual machines, and functions
FundamentalAZ-900 Microsoft Azure Fundamentals Exam
Azure Kubernetes Service
Compare compute types, including containers, virtual machines, and functions
FundamentalAZ-900 Microsoft Azure Fundamentals Exam
Azure Virtual Machines IaaS Full Control
Compare compute types, including containers, virtual machines, and functions
FundamentalAZ-900 Microsoft Azure Fundamentals Exam
Shared Responsibility Model IaaS
Describe the shared responsibility model
ExpertAZ-305 Designing Microsoft Azure Infrastructure Solutions Exam
Azure Monitor Cost Optimization Design
Recommend a monitoring solution
Last updated Validated