NGINX Ingress Controller for multiple service for branch wise deployment - regex

Question

I my case, I have a branch wise deployment in EKS 1.14 and I want to handle this with "regex" & Nginx ingress.
Scenario:- Let's say I have Branch B1 with service_A(apache service), Similarly under B2 with service_A((apache service) and so on and want to access the service via URL like:- apache-{branch_name}.example.com
Note :- Branch B1/B2 is nothing but unique namespaces where same kind of service is running.
I need single ingress from where I can control all different branch URL
My example file:-
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
name: regex-ingress
annotations:
kubernetes.io/ingress.class: "nginx"
cert-manager.io/cluster-issuer: "letsencrypt-prod"
spec:
tls:
- hosts:
- '*.k8s.example.com'
secretName: prod-crt
rules:
- host: {service_A-b1}.k8s.acko.in
http:
paths:
- backend:
serviceName: {service_A-b1}
servicePort: 80
- host: {service_A-b2}.k8s.acko.in
http:
paths:
- backend:
serviceName: {service_A-b2}
servicePort: 80

Answer 1

Nginx ingress don't work in this way, is not possible to have regex in serviceName neither host.
From NGINX docs:
Regular expressions and wild cards are not supported in the spec.rules.host field. Full hostnames must be used.
You can use regex only in path field:
The ingress controller supports case insensitive regular expressions in the spec.rules.http.paths.path field. This can be enabled by setting the nginx.ingress.kubernetes.io/use-regex annotation to true (the default is false).
If you need to control your serviceName and host dinamically I strong recommend use some kind of automation (could be jenkins, bash script etc...) or templates by HELM which will modify at deployment time.
References:
https://kubernetes.github.io/ingress-nginx/user-guide/ingress-path-matching/