<p><strong>NGINX Ingress controller version:</strong> 0.18.0
<strong>Kubernetes version (use kubectl version):</strong> 1.11.1
<strong>Cloud provider or hardware configuration:</strong> Azure (AKS)
<strong>Install tools:</strong> helm</p>

<p><strong>What happened:</strong> The Ingress controller gives a 400 error with a certain GET when a request url/header is "too long".</p>

<p><strong>What you expected to happen:</strong>
The request is passed on to the correct service and pod.</p>

<p><strong>How to reproduce it (as minimally and precisely as possible):</strong>
We use keycloak for authentication. When a user logs in a GET is done with an access token that is generated by keycloak. The access token gives a user certain rights within the application. Users have roles that gives them other/more permissions. When a user has a lot of roles the access token get significally longer which causes the 400 on the ingres controller. With a user with less roles it works fine and we can see the GET request being passed on to the right service..</p>

<p><strong>Anything else we need to know:</strong>
We already tried adjusting header buffer sizes etc from 4k to 8 and 16k but that didn't do anything.
I set the ingress controller loglevel to debug, but it doesn't give any more info on the 400 error.</p>

<p>We solved this issue by also setting the backend service, a Spring Boot service with embedded Tomcat, configuration with server.max-http-header-size: 64000. So the Nginx service and the backend service settings had to be raised.</p>
