Azure SNAT exhaustion - how do I know when it is happening?

Question

We think we are having Azure SNAT exhaustion issues with a group of virtual machines within Cloud Foundry. The machines are not going through a load balancer. I've been through this document: https://docs.microsoft.com/en-us/azure/load-balancer/load-balancer-outbound-connections#snatexhaust

I want to find out how, if possible, to know if we are hitting SNAT exhaustion issues without having to open a support ticket with Microsoft. Remediating or preventing the SNAT issues is NOT what I'm asking about.

Thanks,

Solution 1

I just got off the phone with Microsoft Azure support. At this time, there is no way for us as a customer to see SNAT exhaustion without opening a ticket.

Solution 2

For an Azure WebApp, click Diagnose and solve problems, then in search box type snat then click the SNAT Port Exhaustion item which appears as the result of your search.

Solution 3

I have put in an enhancement request for Microsoft to enable monitoring on it: https://feedback.azure.com/forums/231545-diagnostics-and-monitoring/suggestions/36274288-apim-load-balancer-metrics-to-view-snat-metrics-st

If it sounds like a good solution make sure to up vote it!

Solution 4

The answer may be outdated. With Azure Standard LoadBalancer you will be able to see the following SNAT Metrics.

1. SNAT Connection Count
2. Allocated SNAT Ports
3. Used SNAT Ports

This is not available with Azure Basic Load Balancer, which requires support ticket to get info on SNATS.

Hope it helps.

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Comments

[Admin]

Thanks, that is good information but simply seeing failed connections does not confirm SNAT exhaustion. Seeing the failed connections was a clue we were having an issue but there is no way to confirm SNAT exhaustion w/o a ticket to Microsoft it turns out.

[Sylhare]

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