AZ-104 Question 243
Single answerYou have configured a Standard Azure Load Balancer to distribute inbound requests across two Linux VMs in a backend pool. After adding the second VM, you notice traffic is still flowing only to the original VM, even though both VMs are running normally. What is the most likely step you should verify to ensure proper load distribution?
- A
Add an inbound NAT rule for the newly added VM
- B
Enable session persistence in the load balancer settings
- C
Confirm that the health probe is configured on a port both VMs are listening on
- D
Assign a public IP address directly to the new VM
Show answer and explanation
Correct answer: C
Explanation
When troubleshooting an Azure Load Balancer that fails to route traffic to all backend VMs, confirming the health probe configuration is critical. If the load balancer deems a VM unhealthy (due to a mismatch in probe ports or protocol), that VM will not receive any traffic.
- A. Incorrect.
Inbound NAT rules map a specific port on the load balancer front end to a single VM. They do not balance traffic across multiple VMs.
- B. Incorrect.
Session persistence (or 'sticky sessions') ensures a user session remains on the same VM, but it doesn't solve the underlying issue of the second VM not receiving traffic.
- C. Correct.
If the health probe port on the load balancer does not match the port the VM actually responds on, the VM will appear unhealthy and receive no traffic.
- D. Incorrect.
Backend VMs in a load balanced set typically do not require their own public IP addresses. The load balancer front end IP is used for external connections.