VM vs Other Compute Options¶
Azure offers several ways to run your code. Choosing the right service depends on how much control you need and how you prefer to manage your application.
Detailed Comparison Table¶
| Feature | Virtual Machines | App Service | Functions | Container Apps | AKS |
|---|---|---|---|---|---|
| Responsibility | OS + App | App + Config | Code only | App + Config | Containers + K8s |
| Scaling | Manual / VMSS | Auto-scaling | Serverless | Auto / Event-based | K8s HPA/VPA |
| Cost Model | Pay-per-hour | Per plan / tier | Per execution | Per consumption | Per node / control plane |
| Operational Burden | High | Low | Very Low | Low | High |
| Best Case | OS-level control | Web Apps | Short tasks | Microservices | Orchestration |
Compute Decision Flow¶
flowchart TD
Start[Start: New Compute Resource?] --> Control{Need OS access or custom runtime?}
Control -- Yes --> VM[Virtual Machine]
Control -- No --> Container{Container-based?}
Container -- No --> Web{Web App?}
Web -- Yes --> AppS[App Service]
Web -- No --> Func[Azure Functions]
Container -- Yes --> Scale{High orchestration needs?}
Scale -- Yes --> AKS[Azure Kubernetes Service]
Scale -- No --> ACA[Container Apps]Judgment Criteria¶
Use this table to decide if a VM is truly necessary or if it's overkill for your task.
| Criteria | Choose Virtual Machine (Necessary) | Choose PaaS / Serverless (Overkill) |
|---|---|---|
| Control | Need deep OS-level access or custom kernel | Only need to run code or standard runtime |
| Migration | Legacy "lift-and-shift" without code changes | Modernized or cloud-native code |
| Dependencies | Specialized COM+ or legacy GAC assemblies | Standard web or containerized libraries |
| Hardware | GPU or specific high-memory SKU needs | Standard CPU/RAM requirements |
Warning
Running a single web app on a VM means you are responsible for OS patching, firewall rules, and web server configuration. App Service handles these for you automatically.