Microsoft Azure Architect Design (AZ-301) Practice Exam

In a stateless application deployment, how many public IPs are needed for the load balancer and virtual machines?

1. 1 for load balancer, 0 for VMs

2. 1 for each VM, 1 for load balancer

3. 2 for load balancer, 0 for VMs

4. 0 for load balancer, 1 for each VM

The correct answer is: 1 for load balancer, 0 for VMs

In a stateless application deployment, employing a load balancer is essential for distributing incoming traffic across a set of virtual machines (VMs) to ensure high availability and reliability. When you have a load balancer, you typically need only one public IP address assigned to it. This single public IP serves as the entry point for user requests, which the load balancer then routes to the appropriate VM based on its distribution algorithm (such as round-robin, least connections, etc.). The virtual machines themselves do not require a public IP address in this configuration because they can communicate with the load balancer using private IP addresses. This setup enhances security by minimizing the exposure of virtual machines to the public internet. When only the load balancer has a public IP while the VMs utilize private IPs, it effectively creates a buffer that helps to protect your application and its resources. Additionally, this architecture simplifies management and can reduce costs since fewer public IP addresses are needed. Therefore, having one public IP for the load balancer and zero for the virtual machines aligns perfectly with the requirements for a stateless application deployment, making this approach both efficient and secure.