5.1.1.1. Design for Azure Virtual Machines

💡 First Principle: Infrastructure as a Service (IaaS) provides the ultimate control over the computing environment, making it the ideal choice for migrating legacy applications, running custom software, or meeting specific operating system requirements.

Scenario: You are designing a solution for a company that needs to host a specialized scientific simulation application. This application requires a custom Linux distribution with specific kernel modules and real-time GPU processing, which isn't supported by standard Azure PaaS offerings.

Azure VMs are on-demand, scalable computing resources that give you control over the operating system.

Key Design Considerations:

• Workload Suitability: Ideal for lift-and-shift migrations, custom software, or when full control over the environment is necessary.
• Scalability: Achieved through Virtual Machine Scale Sets (VMSS) for automatic scaling.
• High Availability: Leverage Availability Sets (within a datacenter) or Availability Zones (across datacenters).
• Storage: Choose appropriate managed disk types (Standard HDD, Standard SSD, Premium SSD, Ultra Disk) based on performance and cost.
• Networking: Integrate VMs into Azure Virtual Networks (VNets) for secure communication.
• Management: Requires patching, updating, and managing the OS and installed software. Use Azure Automation and Azure Monitor to assist.
• Cost: Pay-as-you-go, reserved instances, and Azure Hybrid Benefit can optimize costs.

⚠️ Common Pitfall: Using VMs for workloads that could be run more efficiently and cost-effectively on PaaS or Serverless platforms. This leads to unnecessary operational overhead for patching and maintenance.

Key Trade-Offs:

• Control vs. Management Overhead: VMs offer maximum control but come with the highest management responsibility (patching, security, configuration) compared to other compute options.

Reflection Question: How does designing for Azure Virtual Machines (IaaS), leveraging its granular control over the operating system, custom software installations, and networking configurations, fundamentally enable the migration of legacy applications and support highly customized environments in the cloud?