AZ-700 Question 196
Single answerYou manage a Standard SKU Azure Load Balancer in the East US region to distribute traffic among three virtual machines (VMs). Each VM resides in a different subnet, but all subnets belong to the same virtual network and region. You need to create a back-end pool that includes all three VMs without moving them to a single subnet. Which method should you use to add these VMs to the back-end pool so they receive traffic from the load balancer?
- A
Configure a back-end pool using public IP addresses directly assigned to each VM� operating system.
- B
Create a NIC-based back-end pool and associate each VM� network interface card (NIC) with it, ensuring all VMs are in the same region and subscription.
- C
Place all VMs in a single availability set before creating the back-end pool, as separate subnets are not supported by Standard SKU load balancers.
- D
Use an IP-based back-end pool that references each VM� private IP address from different subnets in the same virtual network.
Show answer and explanation
Correct answer: B
Explanation
For a Standard SKU Azure Load Balancer, you can create a back-end pool that spans multiple subnets as long as all subnets are in the same virtual network and region. Microsoft documentation recommends using NIC-based back-end pool membership for most scenarios, ensuring that each VM� network interface is properly associated with the load balancer. Refer to Azure Load Balancer best practices (https://learn.microsoft.com/azure/load-balancer/load-balancer-overview) for more details on how to configure back-end pools reliably.
- A. Incorrect.
Option 1 is incorrect. Standard SKU Load Balancers typically do not route traffic directly to public IPs assigned inside the VM's operating system. Instead, you associate the pool at the NIC or IP configuration level in Azure. Public IP addresses used at the OS level are neither a best practice nor supported for direct load balancer back-end pool membership.
- B. Correct.
Option 2 is correct. With a Standard SKU Load Balancer, you can create a back-end pool that references the NICs of each VM. As long as the VMs are in the same region and subscription, and their NICs are within the virtual network, it doesn't matter if they reside in different subnets; they can be part of the same back-end pool through NIC-based membership.
- C. Incorrect.
Option 3 is incorrect. While placing VMs in an availability set might help with high availability, Standard SKU Load Balancers do support back-end pools that span multiple subnets. There's no requirement to consolidate the VMs into a single subnet or a single availability set specifically for back-end pool membership.
- D. Incorrect.
Option 4 is misleading. While you can create an IP-based back-end pool for private IPs, each individual IP assignment must be associated with a valid NIC or IP configuration in Azure. Simply pointing to private IPs from different subnets without properly associating them with the underlying NIC configuration is not sufficient or recommended for a Standard SKU Load Balancer. The recommended approach is usually NIC-based membership.