Short, friendly explanations for each topic. Mark a topic as learned when it clicks.
Cloud computing means accessing computing resources such as servers, storage, databases and software over a network instead of owning and maintaining all the physical equipment yourself.
🌍 Instead of buying a powerful server for a school application, the school rents computing resources from a cloud provider and accesses them over the internet.
Cloud services can help organizations adjust capacity, maintain service availability, estimate performance, manage resources centrally and use built-in security and governance capabilities.
🌍 An online shop may increase its computing capacity during a busy sale and reduce it when customer traffic falls.
The cloud provider and customer share security and operational responsibilities. The provider manages the physical cloud infrastructure, while the customer remains responsible for certain things such as data, identities and access. The exact division depends on the service.
🌍 A provider secures the physical data centre. A customer must still protect their account, configure access correctly and handle their data responsibly.
Public cloud uses cloud infrastructure offered by a provider to multiple customers. Private cloud infrastructure is dedicated to one organization. Hybrid cloud combines private infrastructure with public cloud services.
🌍 A hospital might keep certain systems in its own private environment while using public cloud services for another application.
Consumption-based pricing charges customers according to measured usage or other pricing factors for a service. It can reduce the need to purchase large amounts of hardware before it is needed.
🌍 A business pays for cloud storage it uses instead of buying and maintaining its own storage equipment upfront.
IaaS provides infrastructure such as virtual machines. PaaS provides a managed platform for building or running applications. SaaS provides a finished application that customers use.
🌍 IaaS is like renting a kitchen and managing much of the equipment. PaaS is like using a prepared kitchen to cook. SaaS is like ordering a ready-made meal.
Serverless lets developers run code or use services without directly managing the underlying servers. Servers still exist, but the cloud provider handles much of their provisioning and maintenance.
🌍 A function runs when a new file arrives and processes that file without the developer having to maintain a dedicated server for the task.
Public cloud uses cloud infrastructure offered to customers by a provider. Private cloud provides a dedicated cloud environment for an organization. Hybrid cloud combines on-premises infrastructure or a private environment with public cloud services.
🌍 A startup that wants to deploy quickly may choose public cloud. An organization needing a dedicated environment may consider private cloud. A hospital that keeps some systems on-premises while using Azure for other workloads may use a hybrid approach.
IaaS provides infrastructure such as virtual machines. PaaS provides a platform for building and deploying applications without managing all the underlying infrastructure. SaaS provides a ready-to-use software application.
🌍 Choose IaaS when you need control over a virtual machine's operating system. Choose PaaS when you want to deploy your application without managing the underlying server operating system. Choose SaaS when you simply want to use a finished application.
An Azure region is a geographic area containing Azure datacenters. Region pairs are designated relationships between certain regions. Sovereign regions are designed for specific government or regulatory requirements.
🌍 An organization may choose a region based on latency, service availability, data residency requirements and resilience needs.
Availability zones are physically separate locations within a supported Azure region, designed with independent infrastructure such as power, cooling and networking to improve resilience.
🌍 A service deploys copies of its workload across supported zones so that a problem affecting one zone is less likely to make every copy unavailable.
Azure resources are individual services or components. Resource groups organize resources, subscriptions provide management and billing boundaries, and management groups organize multiple subscriptions.
🌍 A school may put a web app and its supporting resources in a resource group, organize subscriptions by department, and use a management group to apply governance across those subscriptions.
Compute services provide processing power for applications. Virtual machines provide virtualized computers, containers package applications and dependencies, and functions run code in response to events or requests.
🌍 A legacy application may run on a virtual machine, a packaged web service may run in a container, and a small event-triggered task may run as a function.
Azure offers different ways to host applications. Azure App Service provides a managed platform for web apps and APIs, while virtual machines and container services offer different levels of control and management.
🌍 A developer deploying a standard web application may use Azure App Service instead of configuring and maintaining a virtual machine.
Azure networking connects resources and controls how they communicate. A virtual network provides a private network environment, and subnets divide its address space into smaller network segments.
🌍 A business may place web servers in one subnet and application servers in another, with network rules controlling communication between them.
Azure Storage offers different services for different kinds of data. Blob Storage stores object data, Azure Files provides managed file shares, Queue Storage stores messages, Table Storage stores structured NoSQL data, and managed disks support virtual machines.
🌍 A learning app might store uploaded documents in Blob Storage and use a managed disk for a virtual machine's operating system.
Storage access tiers help balance storage cost and access needs. Redundancy options keep additional copies of data to improve durability and, depending on the option, availability or geographic resilience.
🌍 Frequently used files may use an online tier suited to regular access, while long-term records may use a lower-cost tier if its access requirements are acceptable.
Azure provides tools for transferring files and migrating workloads. The right tool depends on data volume, available connectivity, the source environment and the migration goal.
🌍 A company with a very large dataset and limited network bandwidth might consider an offline transfer appliance instead of sending everything over the internet.
Identity services help establish who a user or application is and control access. Microsoft Entra ID is Microsoft's cloud identity and access management service. Authentication verifies identity; authorization determines permitted actions.
🌍 A student signs in with an account and completes an additional verification step. The system then checks whether the account is allowed to access a particular application.
Azure RBAC assigns roles to identities at defined scopes so users and applications receive the permissions needed to manage Azure resources.
🌍 A developer might receive permission to manage a test resource group without receiving unrestricted control over the whole subscription.
Zero Trust requires explicit verification and treats access as something that must be evaluated rather than automatically trusted. Defense in depth uses multiple security layers to reduce reliance on any single control.
🌍 A company checks identity, limits permissions, protects devices and monitors activity instead of assuming that everyone inside its network is trustworthy.
Microsoft Defender for Cloud helps assess and improve cloud security posture and provides security capabilities for supported cloud workloads.
🌍 A team uses security recommendations to identify a virtual machine that needs a security configuration improvement.
A datacenter is a physical facility containing servers, networking equipment, power systems, and cooling systems. An Azure region is a geographic area containing one or more datacenters. Availability zones are physically separate locations within a supported region.
🌍 A company deploys an application in an Azure region. If it needs protection against a problem affecting one datacenter location, it can consider deploying supported resources across availability zones.
An Azure virtual machine is a software-based computer running in Azure. You select an operating system image and a VM size, and configure resources such as disks and networking. Scale sets help manage groups of similar VMs, availability sets help improve VM availability, and Azure Virtual Desktop delivers virtual desktops and applications.
🌍 A company running a legacy application that needs a particular operating system can host it on an Azure VM. If it needs many similar VM instances, it can consider a Virtual Machine Scale Set.
An Azure Storage account provides a namespace and endpoints for supported Azure Storage services. When creating one, you consider the account type, performance options, redundancy, and the storage services or features your workload needs.
🌍 An application storing images and documents may use Blob Storage through a Storage account. The organization then selects suitable performance and redundancy options based on its requirements.
Azure costs depend on factors such as resource type, usage, region, storage, data transfer and selected pricing options. Cost tools help estimate spending, review actual costs and set budgets or alerts.
🌍 Before deploying an application, a team estimates expected costs with the pricing calculator and then reviews actual spending using cost-management tools.
Azure Policy evaluates resources against organizational rules. Resource locks help prevent accidental changes or deletion. Tags attach metadata to resources to support organization and cost analysis.
🌍 A company uses a policy to restrict deployments to approved regions, a deletion lock to protect a critical resource, and tags to label resources by department.
Microsoft Purview provides data governance capabilities that help organizations discover, understand, classify and govern data across supported environments.
🌍 An organization uses data-governance tools to understand where sensitive business data resides and how it should be managed.
Azure provides several interfaces for managing resources. The portal is a graphical interface, Azure CLI uses commands, Azure PowerShell uses PowerShell commands, and Cloud Shell provides a browser-accessible shell environment.
🌍 A beginner creates a storage account in the portal, while an administrator may use CLI or PowerShell to repeat a deployment consistently.
Azure Resource Manager (ARM) is the deployment and management service for Azure resources. Infrastructure as code describes infrastructure in files that can be versioned and deployed consistently. ARM templates are a declarative way to define Azure infrastructure.
🌍 A team defines its development environment in a template so it can deploy a consistent set of resources repeatedly instead of configuring each resource manually.
Azure Arc extends certain Azure management and governance capabilities to supported resources outside Azure, including on-premises and other cloud environments.
🌍 An organization can use supported Azure management capabilities for servers that run in its own datacenter as well as servers in Azure.
Azure Monitor collects and analyzes monitoring data from supported Azure and application environments. Its capabilities include metrics, logs, alerts and application performance monitoring.
🌍 A team creates an alert when a monitored metric crosses a configured threshold and investigates logs to understand what happened.
Azure Advisor analyzes supported resource configurations and usage data to provide recommendations that can help improve cost, reliability, performance, operational excellence and security.
🌍 Advisor may recommend reviewing an underused resource or improving a supported configuration.
Azure Service Health provides personalized information about Azure service issues, planned maintenance and other health events that may affect the resources or services relevant to an organization.
🌍 An administrator checks Service Health to investigate whether an Azure service incident could explain an application problem.
Azure Monitor focuses on metrics, logs, alerts and application monitoring. Azure Advisor provides optimization recommendations. Azure Service Health reports Azure service issues and planned maintenance relevant to your environment.
🌍 Use Monitor to investigate an application's high response time, Advisor to review optimization suggestions, and Service Health to check whether a platform incident is affecting a service.
Topics follow the public skills outline. For full detail see the official AZ-900 study guide.