How to manage two paths on the same hostname? - kubernetes

Question

I'm using Kubernetes v1.23.16 cluster (One master and three workers) bare metal based.
I have created couple of services in a separate namespace. The same as follows.
$ kubectl get services --all-namespaces
NAMESPACE NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
default kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 11d
app1 app1-service ClusterIP 10.103.151.235 <none> 80/TCP 19h
app2 app2-service ClusterIP 10.105.88.151 <none> 80/TCP 11d
kube-system kube-dns ClusterIP 10.96.0.10 <none> 53/UDP,53/TCP,9153/TCP 11d
Now I'm having below nginx resource yml to access the service outside. For example i would like access as given below.
http://web.example.com/app1
http://web.example.com/app2
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
annotations:
nginx.ingress.kubernetes.io/rewrite-target: /$2
name: app-ingress
spec:
ingressClassName: nginx
rules:
- host: web.example.com
http:
paths:
- path: /app1
pathType: Prefix
backend:
service:
name: app1-service
port:
number: 80
- path: /app2
pathType: Prefix
backend:
service:
name: app2-service
port:
number: 80
When i apply the nginx resource yml file it says service not found error.
$ kubectl describe ingress app-ingress
Name: app-ingress
Labels: <none>
Namespace: default
Address:
Default backend: default-http-backend:80 (<error: endpoints "default-http-backend" not found>)
Rules:
Host Path Backends
---- ---- --------
web.example.com
/app1 app1-service:80 (<error: endpoints "app1-service" not found>)
/app2 app2-service:80 (<error: endpoints "app2-service" not found>)
Annotations: nginx.ingress.kubernetes.io/rewrite-target: /$2
Since my applications services are running in different namespace separately and my nginx resource yml is running in default namespace. So now how do i configure nginx resource file to access both of my service?

Answer 1

An Ingress resource can only refer to Services in the same namespace as the Ingress. To manage two paths on the same hostname that lead to backends in different namespaces, you will need two separate Ingress resources.
In the app1 namespace:
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: app-ingress
namespace: app1
spec:
ingressClassName: nginx
rules:
- host: web.example.com
http:
paths:
- path: /app1
pathType: Prefix
backend:
service:
name: app1-service
port:
number: 80
And in the app2 namespace:
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: app-ingress
namespace: app2
spec:
ingressClassName: nginx
rules:
- host: web.example.com
http:
paths:
- path: /app2
pathType: Prefix
backend:
service:
name: app2-service
port:
number: 80
With these resources in place, requests for http://web.example.com/app1 will go to app1-service, and requests for http://web.example.com/app2 will go to app2-service.
NB: I've removed your nginx.ingress.kubernetes.io/rewrite-target annotation because you're not doing any regex-based path rewriting in this example.
I've put a deployable example online here.

Answer 2

Just remove your rewrite path in single ingress you can achieve it.
If you are creating the multiple make sure to change the name as Larsks suggested else it will overwrite the existing one.
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: app-ingress
spec:
ingressClassName: nginx
rules:
- host: web.example.com
http:
paths:
- path: /app1
pathType: Prefix
backend:
service:
name: app1-service
port:
number: 80
- path: /app2
pathType: Prefix
backend:
service:
name: app2-service
port:
number: 80