Variables in ingress host carried over to service name - amazon-web-services

Question

My current ingress looks something like
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: my-ingress
spec:
rules:
- host: web1.dev.cloud
http:
paths:
- path: /
backend:
serviceName: web1
servicePort: 8080
Meaning that the first part of the host will always match the serviceName.
So for every web pod I would need to repeat the above like:
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: my-ingress
spec:
rules:
- host: web1.dev.cloud
http:
paths:
- path: /
backend:
serviceName: web1
servicePort: 8080
- host: web2.dev.cloud
http:
paths:
- path: /
backend:
serviceName: web2
servicePort: 8080
I was just wondering if there is some support for doing the following:
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: my-ingress
spec:
rules:
- host: $1.dev.cloud
http:
paths:
- path: /
backend:
serviceName: $1
servicePort: 8080

Answer 1

This is not possible if you use kubectl to deploy your kubernetes manifests. However if you write a helm chart for your application it is possible. Helm uses a packaging format called charts. A chart is a collection of files that describe a related set of Kubernetes resources in the form for templates.
There in the inress.yaml template you can write such config using range block and putting the variable values in values.yaml
In your case it will look something like below
spec:
rules:
{{- range .Values.ingress.hosts }}
- host: {{ .name }}.dev.cloud
http:
paths:
- path: {{ default "/" .path | quote }}
backend:
serviceName: {{ .name }}
servicePort: 8080
{{- end }}
and the values.yaml will have
ingress:
hosts:
- name: abc
- name: xyz

Answer 2

Thanks to RAMNEEK GUPTA post, you have solution how it can be automated.
According to the documentation:
Regular expressions and wild cards are not supported in the spec.rules.host field. Full hostnames must be used.
So please try as in your example:
1. Request based on the HTTP URI being requested "Simple fanout"
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: fanout
annotations:
nginx.ingress.kubernetes.io/rewrite-target: /
spec:
rules:
- host: dev.com
http:
paths:
- path: /web1
backend:
serviceName: web1
servicePort: 8080
- path: /web2
backend:
serviceName: web2
servicePort: 8080
2. Requests based on the Host header "Named based virtual hosting"
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
name: Named
spec:
rules:
- host: web1.dev.com
http:
paths:
- backend:
serviceName: web1
servicePort: 8080
- host: web2.dev.com
http:
paths:
- backend:
serviceName: web2
servicePort: 8080