Describe cloud computing

📘Microsoft Certified: Azure Fundamentals (AZ-900)

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Cloud computing is the delivery of computing services—such as servers, storage, databases, networking, security, software, and analytics—over the internet (“the cloud”). Instead of owning and maintaining physical hardware in a local data center, organizations can use resources provided by cloud service providers like Microsoft Azure.

This model allows organizations to access technology on demand, scale quickly, and pay only for what they use.

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Key Characteristics of Cloud Computing (Important for AZ-900)

Microsoft defines several key characteristics that describe cloud computing. These characteristics often appear in exam questions.

1. On-Demand Self-Service

Users can provision (create) IT resources whenever they need them, without waiting for IT staff.

• Example: A developer can create a new virtual machine (VM) in Azure Portal instantly.

2. Broad Network Access

Cloud services are accessible from anywhere through the internet using devices like computers, servers, or mobile devices.

• Example: You can manage Azure services from the Azure Portal or CLI from any internet-connected device.

3. Resource Pooling

Azure uses shared infrastructure to serve many customers simultaneously. Resources are dynamically assigned based on demand.

• Example: Your Azure VM runs on shared physical hardware, but it is isolated for security and performance.

4. Rapid Elasticity

Cloud resources can scale up or down quickly based on workload needs.

• Example: A web application automatically increases its number of servers during high traffic.

5. Measured Service / Pay-As-You-Go

Users pay only for the resources they consume.

• Example: You pay for the exact storage used in Azure Blob Storage or the runtime of an Azure Function.

These characteristics help organizations reduce operational tasks and focus more on business needs rather than hardware maintenance.

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Cloud Computing Models You Must Know

Azure organizes cloud services under three main service models. These are critical for AZ-900.

1. Infrastructure as a Service (IaaS)

Provides basic IT infrastructure like servers, storage, and networking.

• Example: Azure Virtual Machines.
• The user manages: operating system, apps, and data.
• Azure manages: physical hardware.

2. Platform as a Service (PaaS)

Provides a complete development and deployment environment.

• Example: Azure App Service.
• The user manages: applications and data.
• Azure manages: servers, OS, runtime, networking.

3. Software as a Service (SaaS)

Provides fully ready-to-use applications over the internet.

• Example: Microsoft 365.
• Azure manages everything, including the app.

Exam tip:
IaaS = Most control
PaaS = Middle
SaaS = Least control

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Cloud Computing Deployment Models

These explain where the cloud environment is hosted.

1. Public Cloud

The cloud provider owns and manages the infrastructure. Users share the hardware but are isolated securely.

• Example: Azure Public Cloud.

2. Private Cloud

The environment is used only by one organization.

• Example: A company hosts its own private cloud using Azure Stack.

3. Hybrid Cloud

A combination of public and private cloud.

• Example: On-premises servers connected to Azure using VPN or ExpressRoute.

4. Multi-Cloud

Using services from multiple cloud providers.

• Example: Azure + AWS + Google Cloud.

AZ-900 commonly tests the difference between public, private, and hybrid.

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Benefits of Cloud Computing (Highly Tested in AZ-900)

1. Cost Savings

No need to buy expensive servers or maintain data centers.

2. Scalability

Increase or decrease resources based on demand.

3. Reliability

Azure provides high availability and fault tolerance through globally distributed data centers.

4. High Security

Cloud platforms include identity management, threat detection, encryption, and compliance.

5. Global Reach

Azure has data centers around the world, allowing deployment close to users.

6. Productivity

Teams don’t need to maintain hardware—Azure handles updates, patches, and monitoring.

7. Performance

Azure uses modern hardware, fast networking, and optimized environments.

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Shared Responsibility Model (Critical AZ-900 Topic)

Cloud security and management responsibilities are split between the customer and Azure.

Customer Responsibilities (depend on model)

• Data
• Users and identities (like Azure AD accounts)
• Endpoints (such as laptops)
• Applications

Azure Responsibilities

• Physical data centers
• Hardware
• Global infrastructure
• Networking components

For example:

• In IaaS, you manage more (VM OS, apps).
• In SaaS, you manage least (mostly just user accounts).

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Realistic IT-Based Example (Without Real-World Non-IT Analogies)

Imagine an IT team deploying a new internal application:

Without Cloud

• Must buy servers
• Configure networks
• Install operating systems
• Maintain security patches
• Manage storage and backups

With Azure Cloud

• Deploy a VM or App Service in minutes
• Automatically scale the resources
• Use Azure Backup for protection
• Use Azure Monitor for logs and alerts
• Pay only for what is used

This demonstrates why cloud computing is flexible and cost-efficient for IT environments.

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What You Must Remember for AZ-900

To pass the exam, students must know:

✔ Cloud computing definition
✔ Key characteristics (on-demand, scalability, elasticity, pay-as-you-go)
✔ Service models (IaaS, PaaS, SaaS)
✔ Deployment models (public, private, hybrid, multi-cloud)
✔ Benefits of cloud computing
✔ Shared responsibility model
✔ Basic IT-level examples of cloud usage

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