What Is the AZ-900? Glossary & Key Terms

Cloud Computing
The on-demand delivery of IT resources like compute, storage, and networking over the internet with pay-as-you-go pricing.
IaaS
Infrastructure as a Service; a cloud model providing virtualized compute, storage, and networking while the customer manages the OS and above.
PaaS
Platform as a Service; a cloud model where the provider manages the runtime environment so customers can focus only on their application code.
SaaS
Software as a Service; a cloud model delivering a complete, ready-to-use application managed entirely by the provider.
Shared Responsibility Model
The framework describing which security and operational tasks are handled by the cloud provider versus the customer, varying by service type.
Availability Zone
A physically separate location within an Azure region with independent power and networking, used to protect against datacenter failures.
Region Pair
Two Azure regions in the same geography linked together so that one can serve as a disaster-recovery target for the other.
Resource Group
A logical container in Azure used to group related resources for unified management, deployment, and billing.
Azure Resource Manager (ARM)
The deployment and management service that underlies all resource creation, updates, and deletion in Azure.
Management Group
A container that sits above subscriptions in the Azure hierarchy, used to apply governance controls across multiple subscriptions at once.
Virtual Machine (VM)
An emulated, software-based computer running an operating system and applications, provisioned on Azure's IaaS compute service.
Virtual Machine Scale Set
An Azure service that manages a group of identical, load-balanced VMs that automatically scale in or out based on demand.
App Service
A fully managed PaaS platform for building and hosting web apps and APIs without managing servers.
Azure Functions
A serverless compute service that executes small units of code in response to events, billed only for actual execution time.
Container
A lightweight, portable package of an application and its dependencies that shares the host operating system kernel.
Virtual Network (VNet)
The core Azure networking construct that lets resources communicate securely with each other, the internet, and on-premises networks.
VPN Gateway
An Azure service that establishes an encrypted connection over the public internet between an Azure VNet and another network.
ExpressRoute
An Azure service that provides a private, dedicated network connection between on-premises infrastructure and Azure, bypassing the public internet.
Network Security Group (NSG)
A set of rules that filter inbound and outbound network traffic to and from Azure resources within a virtual network.
Blob Storage
An Azure storage service optimized for storing massive amounts of unstructured object data such as documents and media files.
Azure Files
A managed cloud file-share service accessible via the SMB protocol, mountable like a traditional network drive.
Redundancy (LRS/GRS)
Data replication strategies in Azure Storage; LRS copies data within one datacenter, while GRS also copies it to a distant secondary region for disaster protection.
Microsoft Entra ID (Azure Active Directory)
Microsoft's cloud-based identity and access management service used to authenticate users and control access to resources.
Multi-Factor Authentication (MFA)
An authentication method requiring two or more independent proofs of identity before granting access.
Role-Based Access Control (RBAC)
An Azure authorization model that grants permissions to users, groups, or applications by assigning roles scoped to specific resources.