Kubernetes nginx ingress adds internal port - nginx

Question

I have a docker image with Nginx serving a static site. The site is served from a folder, lets call it "folder". When I request http://mydomain/folder/ it works. However when I request http://mydomain/folder it redirects to http://mydomain:8080/folder which is the internal port used by the container. How can I prevent my ingress controller from adding the port?
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
generation: 1
labels:
app.kubernetes.io/instance: administration-env
name: administration-env-erst-env
namespace: default
resourceVersion: "71710149"
selfLink: /apis/extensions/v1beta1/namespaces/default/ingresses/administration-env-erst-env
uid: c89014d2-60fe-11e9-8a63-000d3a2cc488
spec:
rules:
- host: mydomain
http:
paths:
- backend:
serviceName: administration
servicePort: 8080
path: /administration
tls:
- hosts:
- mydomain
secretName: some-tls-secret
status:
loadBalancer:
ingress:
- ip: xx.xx.xx.xx

Answer 1

you can try as a workaround adding a proxy pass in your nginx.conf
something like:
location /folder {
proxy_pass http://mydomain/folder/;
}

Answer 2

if you are using nginx ingress you can do this like
nginx.ingress.kubernetes.io/configuration-snippet
for an nginx location block snippet
nginx.ingress.kubernetes.io/server-snippet
for a snippet in the nginx config service block
server-snippets: |
location /foldername {
proxy_pass http://yourdomain/folder/;
proxy_set_header Upgrade $http_upgrade;
proxy_http_version 1.1;
proxy_set_header X-Forwarded-Host $http_host;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header X-Forwarded-For $remote_addr;
proxy_set_header Host $host;
proxy_set_header Connection "upgrade";
proxy_cache_bypass $http_upgrade;
}