2.3.1. 💡 First Principle: Azure Virtual Machines (VMs)

First Principle: Azure Virtual Machines (VMs) provide on-demand, scalable computing resources (Infrastructure as a Service - IaaS), offering granular control over the operating system and software configurations. Their core purpose is to enable the migration of legacy applications and support highly customized environments in the cloud.

What It Is: An Azure VM is a virtualized server in the cloud that you can use just like a physical computer. You can choose the operating system, hardware specifications, and install any software you need.

Key Concepts:

• Full Control: You manage the OS, patching, and all installed software.
• Scalability: Can be scaled up (more powerful) or out (more instances) using Virtual Machine Scale Sets.
• High Availability: Can be deployed in Availability Sets or Availability Zones to protect against hardware or datacenter failures.

Scenario: A company needs to migrate a legacy application that requires a specific, older version of Windows Server and custom software that cannot be easily containerized or refactored for PaaS.

Reflection Question: When would you choose an Azure Virtual Machine over a PaaS offering like Azure App Service, and what are the key trade-offs in terms of control versus operational overhead?

💡 Tip: Use VMs when you need maximum control over the environment. For web apps, always consider PaaS options like App Service first to reduce management overhead.