Azure App Service, Containers, and Serverless

Quick Answer: Azure App Service = PaaS web hosting. Azure Container Instances = simple containers without VMs. Azure Kubernetes Service = managed container orchestration. Azure Functions = serverless event-driven compute.

Azure App Service (PaaS)

Azure App Service is a fully managed PaaS platform for building, deploying, and scaling web applications, REST APIs, and mobile backends.

Key features:

• Supports multiple languages: .NET, Java, Node.js, PHP, Python, Ruby
• Built-in auto-scaling and load balancing
• CI/CD integration with GitHub, Azure DevOps, Docker Hub
• Custom domains and free SSL/TLS certificates
• Deployment slots for staging and blue-green deployments
• Built-in authentication (Azure AD, Google, Facebook, Twitter)
• Runs on Windows or Linux

App Service Plans: App Service resources run on App Service Plans, which define the compute resources (CPU, memory) available. Plans range from Free and Shared (for dev/test) to Basic, Standard, Premium, and Isolated (for production).

Containers in Azure

Containers package an application and its dependencies into a portable, consistent unit that runs the same anywhere. Azure offers multiple container hosting options:

Azure Container Instances (ACI)

The simplest and fastest way to run a container in Azure. No VMs to manage, no orchestration to configure.

• PaaS — Azure manages the underlying infrastructure
• Per-second billing — Pay only while the container is running
• Fast startup — Containers start in seconds
• Best for: Simple applications, batch jobs, CI/CD tasks, sidecar containers

Azure Kubernetes Service (AKS)

A managed Kubernetes service for deploying, scaling, and managing containerized applications at scale.

• Managed control plane — Azure manages the Kubernetes master nodes (free)
• You manage the worker nodes (VMs) that run your containers
• Auto-scaling — Automatically scale pods and nodes based on demand
• Built-in monitoring — Integration with Azure Monitor and Container Insights
• Best for: Complex microservices architectures, multi-container applications, enterprise-grade container deployments

Azure Container Apps

A serverless container platform built on Kubernetes that abstracts away cluster management.

• Serverless — No cluster management required (unlike AKS)
• Event-driven scaling — Scale based on HTTP traffic, queue length, or custom events
• Scale to zero — Save costs when there is no traffic
• Best for: Microservices, event-driven apps, background processing

Serverless Computing

Azure Functions

Azure Functions is a serverless compute service that runs small pieces of code (functions) in response to events.

Key characteristics:

• Event-driven — Triggered by HTTP requests, timers, queue messages, blob uploads, etc.
• Auto-scaling — Scales from zero to thousands of instances automatically
• Micro-billing — Pay only for execution time (per-second billing)
• Stateless by default — Each invocation is independent (use Durable Functions for state)
• Multiple languages — C#, JavaScript, Python, Java, PowerShell, TypeScript

Pricing plans:

Azure Logic Apps

Azure Logic Apps is a serverless workflow orchestration service that connects apps, data, services, and systems.

• Visual designer — Build workflows using a drag-and-drop designer
• 400+ connectors — Pre-built integrations with Microsoft 365, Salesforce, SAP, and more
• Pay per action — Billed for each action executed in a workflow
• Best for: Business process automation, data integration, system integration

Compute Service Comparison

On the Exam: Questions will describe a scenario and ask which compute service is the best fit. Focus on the KEY differentiator: Does the scenario need full OS control (VMs)? Just web hosting (App Service)? Event-driven code (Functions)? Container orchestration (AKS)?