Seeing the Current active connections per backend endpoint on Load Balancer

Question

I've been scouring online resources for the past week and I can't find an answer to what seems to me a simple request. I'm trying to figure out how to see the number of current active connections to the backend endpoints on my Azure Load Balancer. I've used other load balancer products and this is among the most basic features, yet I can't find how to see this information in Azure. The use case for this data is to allow us to monitor active connections when taking an endpoint off the load balancer for deployments or updates. We want to confirm that those connections have successfully flushed to other endpoints before moving forward with the changes. Can anyone point me to where I can see this without logging into each web server to check connections there?

Answer 1

@Ray Beckwith ,

Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.

Your observation is correct, currently, there are no metrics that could give you the number of current active connections to the backend endpoints from Azure Load Balancer.

However, you can still see the Total number of active connections per Virtual Machine (LB backend).

• The point to note here is that this displays the total number of active connections to this VM, not the one explicitly created via the Load Balancer.
• i.e., if your backend is exposed directly to Internet along with Load Balancer, and is expected to serve requests directly, the effective metric will be the combination of total requests via the LB and the total requests directly from the VM.
• However, looking at your use case "taking an endpoint off the load balancer for deployments or updates" - I believe this should do the trick.

Open the Load Balancer and

• Navigate to "Insights" from the left tab and click "View Detailed Metrics"
  • 
• Make sure you select the appropriate "Time Range" and select "Flow Distribution" tab
  • 
• Below this, you can see the metrics for Inbound Flows - which you can edit as well.
• You can either use "Sum" or "Average" aggregation to understand the current flows to the backend VM.
• Again, this is just a view of the actual VM's metrics (i.e., the metrics are from VMs and not from the Load Balancer itself)
• Data Reference : Metrics for Microsoft.Compute/virtualMachines
  • Metric Name : Inbound Flows

Hope this helps.

Thanks,

Kapil

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