Azure Application Gateway Health Probes are not being resolved correctly by apache/nginx

Greg Bengis

5/13/23, 12:39 PM

I am using Azure ApplicationGateway and have implemented Health Probes. I have a number of health probes, with different domains.

I struggled with Apache for weeks, trying to get a healthy probes, but got nothing but certificate mismatch errors no matter what I tried.

After a lot of pain, and switching to nginx as a test, I've discovered that the probe hostnames are not matching correctly to the right server configuration, but rather are defaulting to the first SSL config as determined by alphabetical filename order.

This means that the health check on Azure passes for whichever config is first in the list and fails with a certificate mismatch error for all the others.

When accessing these urls of the probems via browser, these SSL configurations all work correctly.

Without going into configs etc, my question is this: What could be the possible reason that requests from a probe do not resolve correctly (fails to match 'virtualhost'), yet it's fine in my browser? I've added logging to check the $host name is correct, so that's not the issue. I assume something similar happened with Apache, which could point to something system level? I don't really know how to diagnose this further - I am not finding similar issues on Google. Any help appreciated.

0 + 0

nginx

health

ssl-certificate

azure

apache2

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Azure Application Gateway Health Probes are not being resolved correctly by apache/nginx

TH: Azure Application Gateway Health Probes ไม่ได้รับการแก้ไขอย่างถูกต้องโดย apache/nginx

RO: Probele de sănătate Azure Application Gateway nu sunt rezolvate corect de apache/nginx

RU: Зонды работоспособности Шлюза приложений Azure не разрешаются правильно apache/nginx

VI: Thăm dò sức khỏe cổng ứng dụng Azure không được apache/nginx giải quyết chính xác

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