Recently we did upgrade our kong-version from version 1.1 to version 1.3 and kong-ingress-controller-version from 0.3.0 to 0.6.0.
We are running keycloak behind the kong, so when we do hit to keycloak server, its getting below error:
Kong Error
An invalid response was received from the upstream server.
This suggests that the upstream (Keycloak in your case) closed the connection while the response was being read from Kong.
Do you seen any logs in Keycloak which suggest why it is abruptly closing the connections?
FYI I have this error with nginx + keycloak 11, so it’s not a kong issue (I just stumbled accross this thread).
I’m pretty sure it’s Keycloak/Undertows/Wildflys doing something wrong here.
Just wanted to throw in my two cents. I’m still trying to investigate this issue further.
Has anybody been able to get any further solving this issue?