What is the name of the domain?
example.com
What is the error number?
http 520 error
What is the error message?
Error 520: web server returns an unknown error
What is the isssue you’re encountering
Some requests are not forwarded to our webserver and end up in http 520 errors
What steps have you taken to resolve the issue?
Since 1 Week ~1% of all HTTP calls just fail with a 520 HTTP error message on our proxied AKS cluster
- We have checked all nginx ingress and trace logs / worked directly with Azure AKS / MS Support
- It looks like we never received the call, we even build a simulator that can generate 520s, somehow it looks like it has something to do with the load of a single client IP
- Important: We have tried to execute the same calls directly with disabled proxy and do not receive any error messages
- It looks like it has to do something with load per single client IP, if we increase the number of calls then the likelihood of a 520 is higher (but this is just an assumption and could be a statistical ‘correlation’ somehow)
What are the steps to reproduce the issue?
We have already opened a ticket, but only gotten bot / standard answers for a week now and no one is really trying to review the CF-Ray ID we have provided.