What Is Microsoft Azure? Cloud Platform Overview

What Azure actually is

At its core, Azure is a network of Microsoft-owned data centers that you rent hardware and software from. Instead of buying a server, you ask Azure for one, pay by the second while you use it, and release it when you are done. The same model applies to databases, networking, storage, and AI services.

Microsoft launched Azure in 2010, calling it “Windows Azure” at the time. It was originally focused on .NET applications and Windows virtual machines. Today it supports Linux equally well, offers first-class support for open-source languages and frameworks, and runs workloads from containerized microservices to mainframe migrations.

Azure groups its services into categories:

• Compute — Virtual Machines, App Service, Azure Functions, Azure Kubernetes Service (AKS)
• Storage — Blob Storage, Azure Files, Queue Storage, Table Storage
• Databases — Azure SQL Database, Cosmos DB, Azure Database for PostgreSQL/MySQL, Azure Cache for Redis
• Networking — Virtual Network, Azure Load Balancer, Azure CDN, Azure DNS, Application Gateway
• Identity and security — Microsoft Entra ID, Azure Key Vault, Azure Defender
• DevOps and developer tools — Azure DevOps, Azure Pipelines, Azure Container Registry
• AI and machine learning — Azure OpenAI Service, Azure Machine Learning, Cognitive Services
• Monitoring — Azure Monitor, Application Insights, Log Analytics

You don’t need to use all of these. Most teams start with two or three services and add more as needs grow.

Why organizations choose Azure over other clouds

Azure’s biggest differentiator is its Microsoft ecosystem integration. If your organization already uses any of the following, Azure reduces friction significantly:

• Windows Server and Active Directory — Azure Active Directory (now called Microsoft Entra ID) is the cloud version of AD, and the two sync seamlessly. Your existing user accounts, groups, and policies transfer.
• Office 365 and Microsoft 365 — These services run on Azure infrastructure. Single sign-on between your apps and Microsoft 365 is straightforward with Entra ID.
• SQL Server — Azure SQL Database is a fully managed version of SQL Server. Migrations from on-premises SQL Server are well-supported with the Azure Database Migration Service.
• Visual Studio and GitHub — Microsoft owns GitHub, and Azure DevOps integrates directly into Visual Studio. The toolchain between development, CI/CD, and deployment is tightly connected.

Azure also has a strong hybrid cloud story. Azure Arc lets you manage on-premises servers, Kubernetes clusters, and even resources in other clouds through the Azure portal, using the same Azure RBAC, policies, and monitoring. This matters to enterprises that cannot move everything to the cloud immediately.

How Azure compares to AWS and GCP

All three major clouds offer similar capabilities. The differences are in emphasis, pricing, and ecosystem fit.

If your team is greenfield with no existing infrastructure, all three are reasonable starting points. If you already run Windows Server, SQL Server, or Active Directory on-premises, Azure will feel familiar and integrate more smoothly.

Three ways to interact with Azure

Azure gives you three main interfaces. Most people start with the portal and then move toward CLI or infrastructure-as-code as they get more comfortable.

1. The Azure Portal

The portal at portal.azure.com is a web UI where you can create, configure, and monitor resources. It is the easiest starting point. You can point and click to spin up a virtual machine, configure a storage account, or set a budget alert. The downside is that manual portal actions don’t produce repeatable infrastructure — if you delete something, recreating it from memory is error-prone.

2. The Azure CLI

The Azure CLI (az) is a command-line tool that runs on Windows, macOS, and Linux. Once installed and authenticated, you can automate and script anything you can do in the portal. For example:

# Log in to Azure
az login

# List all subscriptions on your account
az account list --output table

# Create a resource group in East US
az group create --name my-rg --location eastus

# List all resources in that group
az resource list --resource-group my-rg --output table

The CLI is the fastest way to experiment from a terminal and is essential for CI/CD pipelines. See the Azure CLI overview and how to install the Azure CLI to get set up.

3. The REST API

Everything Azure does — portal clicks, CLI commands — ultimately calls the Azure Resource Manager REST API. You can call it directly with any HTTP client. This is mostly useful when you’re building tools that need to integrate with Azure programmatically or when the CLI doesn’t expose a feature yet. See Azure REST APIs for an introduction.

A real scenario: a startup moving off on-premises

Here is what Azure looks like in practice. Consider a small software company with 15 engineers. They currently run their application on two physical servers in a rented rack. The servers are aging, backups are manual, and scaling for traffic spikes means buying more hardware.

When they move to Azure, here is what changes:

1. Compute — Their application moves to Azure App Service (a managed platform for web apps). No OS patching, no server management. They pay only for the compute tier they choose, and scaling up takes a slider in the portal.
2. Database — Their SQL Server database moves to Azure SQL Database. Backups are automatic. Point-in-time restore is built in. High availability is on by default.
3. Identity — They set up Microsoft Entra ID. Engineers log in once and get access to Azure resources, the company’s Microsoft 365 email, and the GitHub organization — all with the same credentials and MFA.
4. CI/CD — They connect their GitHub repositories to Azure Pipelines. Every pull request triggers a test run, and merges to main automatically deploy to a staging environment.
5. Monitoring — Application Insights is added to the app. They can see real-time request rates, error rates, and performance traces in a dashboard without writing any logging infrastructure.
6. Cost — Instead of a fixed monthly rack rental fee plus hardware depreciation, they pay for actual usage. During off-hours, the staging environment scales down to near zero.

This scenario uses six Azure services, none of which require the team to manage physical infrastructure. That’s the practical value of cloud computing — not just “someone else’s servers,” but a set of managed services that replace operational work.

Azure’s global footprint

Azure operates in more than 60 regions across every major continent. A “region” is a geographic area containing one or more data centers. Most regions also offer availability zones — physically separate buildings within the same region with independent power and networking. Availability zones let you build applications that survive a single data center failure.

Azure also operates sovereign clouds for specific regulatory contexts:

• Azure Government — US government agencies and contractors, physically isolated from commercial Azure
• Azure China — Operated by 21Vianet, physically isolated, required by Chinese law
• Azure Germany — A data trustee model (largely superseded by the standard Azure Germany region)

For most organizations, the commercial Azure regions are the right choice. For compliance-sensitive cases, see Azure global infrastructure for how to pick a region and what sovereign cloud restrictions apply.

Before you start: what you need to understand first

Azure has a few concepts that are unlike anything in traditional IT, and misunderstanding them early causes real problems later. The short list:

• Subscriptions are your billing and access boundary. Every resource belongs to a subscription. See Azure subscriptions.
• Resource groups are containers for related resources. You cannot create a resource without putting it in a resource group.
• RBAC roles control who can do what. Access is granted at the subscription, resource group, or individual resource level. See Azure identity basics.
• Regions matter for latency, compliance, and availability. Not every service is available in every region.

The pages in this section walk through each of these concepts in detail. Start with subscriptions, then the resource hierarchy, and you’ll have a solid mental model before touching any actual services.