5.1 When You Need a VM
Why. Not every website needs a full VM. But learning Linux + Nginx on a VM teaches fundamentals that App Service hides.
What. A Virtual Machine is a rented computer (CPU, RAM, disk, NIC) you patch and manage. App Service is a managed web host (later chapter) with less OS work.
How. For Volume 1 we create a small Ubuntu VM to learn SSH and Nginx. Production teams often mix VMs and managed services.