4.1.4. Configure Load Balancing for VMs

💡 First Principle: Load balancing is a fundamental strategy for achieving high availability and scalability by distributing incoming network traffic across multiple healthy backend resources, preventing any single resource from becoming a bottleneck or a single point of failure.

Scenario: You need to deploy a web application that receives a large volume of incoming HTTP/HTTPS traffic. This application must be highly available, scalable, and protected from common web exploits.

This task delves into the practical application of load balancing services. You'll explore how to:

• Configure Azure Load Balancer: Distribute traffic at Layer 4 (TCP/UDP) for high performance.
• Configure Azure Application Gateway: Manage web traffic at Layer 7 (HTTP/HTTPS) with advanced routing and Web Application Firewall (WAF) capabilities.
• Implement Azure Virtual Machine Scale Sets (VMSS): Deploy and manage a group of identical, load-balanced VMs that can automatically scale based on demand.

Mastering these concepts is crucial for the AZ-104 exam, as it assesses your ability to implement scalable and highly available compute solutions.

⚠️ Common Pitfall: Choosing the wrong type of load balancer for the workload. For example, using a Layer 4 Azure Load Balancer when you need Layer 7 features like URL-based routing or SSL offloading.

Key Trade-Offs:

• Performance/Simplicity (Layer 4) vs. Features/Intelligence (Layer 7): A Layer 4 load balancer is faster and simpler but less intelligent. A Layer 7 load balancer offers advanced features but has slightly more overhead.

Reflection Question: How do Azure's load balancing solutions (Azure Load Balancer, Azure Application Gateway), when combined with Virtual Machine Scale Sets, fundamentally ensure high availability, scalability, and protection for your web applications by distributing traffic and automatically scaling VMs?