how to customize k8s nginx ingress HTTP headers error - kubernetes

Question

in our cluster, there's a customized error pages backend and a auth service
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
annotations:
nginx.ingress.kubernetes.io/use-regex: 'true'
nginx.ingress.kubernetes.io/auth-url: 'http:/***/auth'
https://kubernetes.github.io/ingress-nginx/user-guide/custom-errors/
https://github.com/kubernetes/ingress-nginx/tree/master/images/custom-error-pages
From above link and the log show in error pages backend from auth service 401, it only have 8 hardcode heades like below.
2020/04/14 03:24:35 request info &{GET /?access_token=pk1.eyJ1Ijoid2ViZXJ0YW8iLCJhIjoiY2pibTdmaWc2MTZqaDJybzFzcm93bGE2eiJ9.cwSE9DYCYP0dIeY4Hhp6Kg HTTP/1.0 1 0 map[Accept:[/] Accept-Encoding:[gzip, deflate, br] Cache-Control:[no-cache] Connection:[close] Postman-Token:[c7d07b51-5e3d-469d-9ec4-73be2cf5cd26] User-Agent:[PostmanRuntime/7.24.0] X-Code:[401] X-Format:[/] X-Ingress-Name:[static-api-ingress] X-Namespace:[default] X-Original-Uri:[/xxxx/-76.9,38.9,15/1000x1000#1x?access_token=pk1.eyJ1Ijoid2ViZXJ0YW8iLCJhIjoiY2pibTdmaWc2MTZqaDJybzFzcm93bGE2eiJ9.cwSE9DYCYP0dIeY4Hhp6Kg] X-Service-Name:[static-api-svc] X-Service-Port:[80]] {} 0 [] true api.staging.versalinks.net map[] map[] map[] 172.20.0.70:11440 /?access_token=pk1.eyJ1Ijoid2ViZXJ0YW8iLCJhIjoiY2pibTdmaWc2MTZqaDJybzFzcm93bGE2eiJ9.cwSE9DYCYP0dIeY4Hhp6Kg 0xc00009e0c0}
Is it possible we can add some customized header X-AUTH-INFO from auth service?

Answer 1

You can use Custom Headers for nginx ingress controller via a ConfigMap to pass a custom list of headers to the upstream server.
You should define ConfigMap with your custom headers:
apiVersion: v1
data:
X-Different-Name: "true"
X-Request-Start: t=${msec}
X-Using-Nginx-Controller: "true"
kind: ConfigMap
metadata:
name: custom-headers
namespace: ingress-nginx
This defines a ConfigMap in the ingress-nginx namespace named custom-headers, holding several custom X-prefixed HTTP headers.
apiVersion: v1
data:
proxy-set-headers: "ingress-nginx/custom-headers"
kind: ConfigMap
metadata:
name: nginx-configuration
namespace: ingress-nginx
labels:
app.kubernetes.io/name: ingress-nginx
app.kubernetes.io/part-of: ingress-nginx
This defines a ConfigMap in the ingress-nginx namespace named nginx-configuration. This controls the global configuration of the ingress controller, and already exists in a standard installation. The key proxy-set-headers is set to cite the previously-created ingress-nginx/custom-headers ConfigMap.
The nginx ingress controller will read the ingress-nginx/nginx-configuration ConfigMap, find the proxy-set-headers key, read HTTP headers from the ingress-nginx/custom-headers ConfigMap, and include those HTTP headers in all requests flowing from nginx to the backends.