Azure App Service
What it is
Azure App Service is Azure’s Platform as a Service (PaaS) for hosting web apps, APIs, and mobile backends. You deploy your code and App Service manages the OS, patching, scaling, TLS, and load balancing for you. No VMs to manage — you focus on the app.
Why it exists
Hosting a website by hand means provisioning VMs, installing a web server, patching the OS, and scaling manually. App Service abstracts all of that: deploy (via Git, ZIP, DevOps, or CI/CD) and the platform keeps it running and scales it on a plan.
Key ideas
- Choice of runtime: .NET/.NET Core, Java, Node.js, Python, PHP, and containers (Linux/Windows).
- Runs on an App Service plan, which defines the pricing tier / SKU and capacity; the app itself is the “web app” (site) on the plan.
- Built-in security: managed TLS/SSL, App Service authentication (Entra/social), IP/access restrictions, Managed identities, VNet integration.
- Deployment features: deployment-slots (staging), continuous deployment from GitHub/Azure DevOps, App Service Deployment Center.
- Scaling: scale up (bigger SKU) and scale out (more instances on the plan) — same tier and instance limits as the plan.
- Monitoring: Azure Application Insights for app telemetry and logs.
- Backup/restore and custom domains with managed certificates.
How it fits (diagram)
Exam notes
- App Service = PaaS; you do not patch OS (+ automatic platform patching). Contrast with VMs.
- Deployment slots let you validate a warm deployment then swap (zero downtime).
- Custom domain + TLS binding; App Service Authentication (identity module) for Entra/social auth without code.
- The plan determines scale limits/size; multiple apps can share one plan.
- AZ-104: App Service authentication, deployment slots, scaling via plan, and Application Insights telemetry are the focus areas.
Related
Path MOC · app-service-plan · deployment-slots · azure-functions
📘 Source: Microsoft Learn — App Service