Some tips.
K8S ingresses based on nginx. Even out of K8S, the configuration templates can be used as a source of information.
Ignored if out of the if block, don't know why (probably because if is evil).
location @backend {
internal;
if ($request_filename ~* \.(jpg|jpeg|gif|png|bmp|ico|pdf|flv|swf|txt|css|js|otf|eot|svg|ttf|woff|woff2|map)$) {
expires 7d;
add_header "Cache-control" "public";
add_header "Access-Control-Allow-Origin" "*";
access_log off;
}
include rdbp/proxy.conf;
proxy_pass http://ngxps-backend:3080;
proxy_pass_header Cache-Control;
}