Serverless vs PaaS vs IaaS decision in Azure - Practice Questions

Challenge - 5 Problems

🧠 Conceptual

intermediate

Choosing the best Azure service model for a simple event-driven app

You want to build a small app that runs code only when a user uploads a file. You want to pay only when the code runs and avoid managing servers.

Which Azure service model fits best?

A Azure Blob Storage because it stores files but does not run code.

B Azure Virtual Machines (IaaS) because you get full control over the server and can install any software.

C Azure App Service (PaaS) because it automatically scales but you pay for reserved compute even if idle.

D Azure Functions (Serverless) because it runs code on demand and you pay per execution.

💡 Hint

Think about paying only when code runs and not managing servers.

Azure Functions is serverless, so it runs code only when triggered and charges per execution. This fits event-driven apps well.

❓ Architecture

intermediate

Selecting Azure service model for a web app needing custom OS configuration

You need to deploy a web app that requires installing custom OS software and full control over the environment.

Which Azure service model should you choose?

A Azure App Service (PaaS) because it manages OS and runtime for you.

B Azure Functions (Serverless) because it automatically scales without OS management.

C Azure Virtual Machines (IaaS) because it gives full control over OS and software installation.

D Azure Logic Apps because it is for workflow automation, not custom OS control.

💡 Hint

Think about needing full OS control and custom software installation.

Azure Virtual Machines provide full control over the OS and installed software, suitable for custom configurations.

✅ Best Practice

advanced

Cost optimization for a continuously running web app with moderate traffic

You have a web app that runs 24/7 with moderate traffic. You want to minimize management overhead and optimize cost.

Which Azure service model is the best choice?

A Azure App Service (PaaS) to reduce management overhead and pay for reserved compute.

B Azure Virtual Machines (IaaS) to control costs by managing VM size and uptime.

C Azure Functions (Serverless) because it charges only when code runs, ideal for continuous apps.

D Azure Container Instances because they are for short-lived containers, not continuous apps.

💡 Hint

Consider a service that reduces management but supports continuous running.

Azure App Service is PaaS that manages infrastructure and supports continuous apps with moderate traffic, balancing cost and management.

❓ security

advanced

Security responsibility in Azure service models

Which Azure service model requires you to manage the most security responsibilities, including OS patching and network configuration?

A Azure Virtual Machines (IaaS) because you manage OS, network, and app security.

B Azure App Service (PaaS) because you manage app security but not OS patching.

C Azure Functions (Serverless) because you manage code security only.

D Azure SQL Database (PaaS) because Microsoft manages OS and database security.

💡 Hint

Think about who manages OS and network security in each model.

In IaaS, you manage OS patching, network settings, and app security. PaaS and Serverless offload OS and infrastructure security to Azure.

❓ service_behavior

expert

Behavior of Azure Functions under heavy load

You deploy an Azure Function with a consumption plan. What happens when many events trigger the function simultaneously?

A Azure Functions queue the events and process them one by one on a single instance.

B Azure Functions automatically scale out by creating more instances to handle the load.

C Azure Functions reject new events until the current instance finishes processing all events.

D Azure Functions require manual scaling to handle increased load.

💡 Hint

Think about serverless scaling behavior on demand.

Azure Functions on a consumption plan automatically scale out by adding instances to handle many simultaneous events.