Azure Fundamentals Interview Q&A - Part 1

Group 1: Cloud Computing & Microsoft Azure

1. What is Cloud Computing?

Priority: High

Cloud computing delivers computing resources such as servers, storage, databases, and networking over the internet on demand.

Key Points: On-demand resources, scalability, pay-as-you-go pricing, and reduced hardware maintenance.

2. What is Microsoft Azure?

Priority: High

Microsoft Azure is Microsoft's cloud computing platform for hosting applications, managing databases, storage, networking, security, and other cloud services.

Example: Azure App Service hosts ASP.NET Core Web APIs.

3. What are the five major advantages of Azure?

Priority: High

1. Cost Optimization: Reduces upfront infrastructure investment.

2. Scalability: Adjusts resources based on demand.

3. High Availability: Supports redundancy and fault tolerance.

4. Security: Provides identity, access control, and security services.

5. Global Reach: Deploys applications across geographic regions.

4. What is the difference between On-Premises and Cloud Computing?

Priority: High

5. What is CapEx vs OpEx?

Priority: High

• CapEx (Capital Expenditure): Upfront investment in physical infrastructure, such as purchasing servers.

• OpEx (Operational Expenditure): Ongoing operational expenses, such as monthly Azure service charges.

Key Point: On-premises is typically CapEx-heavy; cloud is typically OpEx-heavy.

6. What is Pay-as-You-Go in Azure?

Priority: Medium

Pay-as-you-go is a pricing model where customers pay for the Azure resources they provision or consume, according to service-specific billing rules.

Example: An Azure VM can incur compute charges while running, even when no users access it.

7. What is Scalability in Cloud Computing?

Priority: High

Scalability is the ability to increase or decrease computing resources based on application demand.

Example: Increasing Azure App Service instances during heavy website traffic.

8. What is the difference between Vertical and Horizontal Scaling?

Priority: High

• Vertical Scaling (Scale Up): Increase CPU, RAM, or capacity of an existing server.

• Horizontal Scaling (Scale Out): Add more servers or application instances.

Vertical Scaling:
VM (2 CPU, 4 GB)
       |
       v
VM (4 CPU, 8 GB)

Horizontal Scaling:
      Load Balancer
        /      \
       v        v
     VM 1      VM 2

9. What is High Availability in Azure?

Priority: High

High availability means designing applications to remain accessible despite certain infrastructure or component failures.

Key Points: Redundancy, availability zones, load balancing, and failover.

10. What is the difference between Scalability and High Availability?

Priority: High

• Scalability: Handles increasing or decreasing workloads.

• High Availability: Minimizes downtime during failures.

Example: Adding servers increases capacity; redundant servers with failover improve availability.

Group 2: Cloud Service Models – IaaS, PaaS, SaaS

11. What are the three main Cloud Service Models?

Priority: High

• IaaS: Infrastructure as a Service — virtual infrastructure.

• PaaS: Platform as a Service — managed application platform.

• SaaS: Software as a Service — ready-to-use software.

12. What is IaaS in Azure?

Priority: High

IaaS provides virtual servers, storage, and networking. Microsoft manages physical infrastructure, while customers manage the guest OS, applications, and configuration.

Example: Azure Virtual Machines.

13. What is PaaS in Azure?

Priority: High

PaaS provides a managed platform to develop, deploy, and run applications without managing the underlying operating system.

Examples: Azure App Service, Azure SQL Database, and Azure Functions.

14. What is SaaS? Give examples.

Priority: High

SaaS provides complete software applications accessed through the internet. The provider manages the software and underlying infrastructure.

Examples: Microsoft 365, Microsoft Teams, and Azure DevOps Services.

15. What is the difference between IaaS, PaaS, and SaaS?

Priority: High

16. Who is responsible for security in IaaS, PaaS, and SaaS?

Priority: High

• IaaS: Customer secures the guest OS, applications, identities, and data.

• PaaS: Provider secures infrastructure and platform; customer secures applications, identities, and data.

• SaaS: Provider secures the application infrastructure; customer manages users, access, and data responsibilities.

Key Point: Cloud security follows the Shared Responsibility Model.

17. When would you choose IaaS over PaaS?

Priority: High

Choose IaaS when applications require operating-system control, custom server configurations, or legacy dependencies.

Example: Migrating an existing ASP.NET application that requires Windows Server and IIS configurations.

18. When would you choose PaaS over IaaS?

Priority: High

Choose PaaS when you want to focus on application development and deployment without maintaining operating systems or servers.

Example: Hosting an ASP.NET Core Web API in Azure App Service.

19. Is Azure SQL Database IaaS or PaaS?

Priority: High

Azure SQL Database is a PaaS offering. Microsoft manages database infrastructure, OS maintenance, and platform patching.

Key Point: Customers manage databases, queries, access permissions, and application data.

20. Is Azure Virtual Machine IaaS or PaaS?

Priority: High

Azure Virtual Machine is IaaS because Microsoft provides virtual infrastructure while customers manage the guest operating system and installed applications.

Example: Windows Server VM running IIS and an ASP.NET Core application.

Group 3: Azure Services & Microsoft Integration

21. What are the commonly used Azure services for .NET developers?

Priority: High

22. What is Azure App Service?

Priority: High

Azure App Service is a managed PaaS offering for hosting web applications, REST APIs, and backend services.

Key Points: Supports .NET, deployment slots, scaling, HTTPS, and CI/CD integration.

23. What is the difference between Azure App Service and Azure Virtual Machine?

Priority: High

• App Service: PaaS; Microsoft manages the OS and hosting infrastructure.

• Virtual Machine: IaaS; customer manages the guest OS, IIS, and application environment.

Key Point: App Service reduces server administration, while VMs provide greater control.

24. How does Azure integrate with existing Microsoft technologies?

Priority: Medium

Azure integrates with .NET, SQL Server, Windows Server, and identity technologies to support cloud migration and modernization.

Examples: IIS hosting → App Service; SQL Server → Azure SQL Database or SQL Managed Instance, depending on compatibility.

Group 4: Hybrid Cloud & Deployment Models

25. What is Hybrid Cloud?

Priority: High

Hybrid cloud combines on-premises or private infrastructure with public cloud services.

Example: ASP.NET Core Web API hosted in Azure connecting to an on-premises SQL Server database.

26. Why do organizations choose Hybrid Cloud?

Priority: High

Organizations use hybrid cloud for gradual migration, legacy application integration, regulatory requirements, and workload flexibility.

Key Point: It allows existing infrastructure and cloud services to work together.

27. What is Public Cloud vs Private Cloud vs Hybrid Cloud?

Priority: High

28. How can Azure connect securely to an On-Premises network?

Priority: Medium

Azure can connect to on-premises networks through Site-to-Site VPN or Azure ExpressRoute.

Key Points: VPN uses encrypted tunnels over the internet; ExpressRoute provides private connectivity through a connectivity provider.

Group 5: Real-Time Scenario-Based Questions

29. How would you host an Angular + ASP.NET Core Web API + SQL Server application in Azure?

Priority: High

Use Azure Static Web Apps for Angular, Azure App Service for the ASP.NET Core API, and Azure SQL Database for relational data.

           Users
             |
             v
    Azure Static Web Apps
          (Angular)
             |
             v
      Azure App Service
     (ASP.NET Core API)
             |
             v
      Azure SQL Database

Supporting Services:
---------------------
Azure Key Vault
Azure Monitor
Application Insights
Azure DevOps Pipelines

Key Point: This architecture primarily uses managed cloud services, reducing infrastructure administration.

30. A company wants to migrate its legacy ASP.NET application without major code changes. Which cloud model would you recommend?

Priority: High

Start by evaluating IaaS using Azure Virtual Machines when the application depends on custom Windows Server or IIS configurations.

Key Point: Lift-and-shift migration can minimize application changes. Evaluate PaaS if the application is compatible.