How to change proxy_buffer sizes in nginx gateway ?

[atomicloopzilla]

I use .net 7 application with OpenId authentication.
.net implementation uses large cookies to store auth information for the session. After sucessful log-in, I'm getting next error:
"*238 upstream sent too big header while reading response header from upstream" so I'm getting "502 Bad Gateway".
There's not enough proxy_buffer size for headers... Default one is 8Kb and seems need to increase it.

I'm using Kubernetes Gateway API, so I hope that there's some way to set annotations somehow, so the nginx will use them..
In ingress nginx, you could do it by adding annotations for ingress:
nginx.ingress.kubernetes.io/proxy-buffers: "8 16k"
nginx.ingress.kubernetes.io/proxy-buffer-size: "32k"
But how can I do it via modern Gateway API (Gateway or HTTPRoute) ?
Please help.

[salonichf5]

We currently do not support this but plan to do so in the future. The workaround to configure those directives at the http context level by modifying this file https://github.com/nginxinc/nginx-gateway-fabric/blob/bcc6ac6da5be1a88d8edf8477600b3a9ac7959fb/internal/mode/static/nginx/conf/nginx.conf and building the image — https://docs.nginx.com/nginx-gateway-fabric/installation/building-the-images/
it is also possible to replace that conf file without building the image using this approach — #1245 (comment)

[mpstefan]

To add on to this answer, we specifically will be looking at implementing an easy way to configure this early next year. We have a design for applying policies, including NGINX configuration, that should solve a lot of the problems the ingress annotations had.

I created an issue to track for this here.