Kubernetes Ingress Exact not prioritized over Prefix

Question

In Kubernetes we need a new service to handle the root path, but but still a catch everything else on our current frontend.

Current frontend Ingress

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: current-frontend
  labels:
    app: current-frontend
    tier: frontend
  annotations:
    kubernetes.io/ingress.class: nginx
spec:
  tls:
    - hosts:
      - my.domain.com
      secretName: tls-secret
  rules:
    - host: my.domain.com
      http:
        paths:
          - backend:
              service:
                name: current-frontend
                port:
                  number: 80
            path: /
            pathType: Prefix

New service Ingress

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: new-service
  labels:
    app: new-service
    tier: frontend
  annotations:
    kubernetes.io/ingress.class: nginx
spec:
  tls:
  - hosts:
    - my.domain.com
    secretName: tls-secret
  rules:
  - host: my.domain.com
    http:
      paths:
      - backend:
          service:
            name: new-service
            port:
              number: 80
        path: /someendpoint
        pathType: ImplementationSpecific
      - backend:
          service:
            name: new-service
            port:
              number: 80
        path: /
        pathType: Exact

According to the documentation of Kuberntes Ingress, it should prioritize Exact over Prefix

If two paths are still equally matched, precedence will be given to paths with an exact path type over prefix path type.

https://kubernetes.io/docs/concepts/services-networking/ingress/#multiple-matches

The problem is that everything else then my.domain.com/someendpoint goes to the current-frontend, while the expected would be that my.domain.com/ would go to new-service.

How do I achieving this?

Solution

I got it working, even If it doesn't seams to be the optimal solution (According to the Documentation)

I Followed Hemanth Kumar's answer and changed the Current Frontend to use Regex, with (.+) instead of (.*) as I wanted at least one char after the slash for it to be hit.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: current-frontend
  labels:
    app: current-frontend
    tier: frontend
  annotations:
    nginx.ingress.kubernetes.io/use-regex: "true"
    kubernetes.io/ingress.class: nginx
spec:
  tls:
    - hosts:
      - my.domain.com
      secretName: tls-secret
  rules:
    - host: my.domain.com
      http:
        paths:
          - backend:
              service:
                name: current-frontend
                port:
                  number: 80
            path: /(.+)
            pathType: Prefix

At the same time I needed to change the New service to use Prefix instead of Exact as it does not work, event if there is no other services to hit.

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: new-service
  labels:
    app: new-service
    tier: frontend
  annotations:
    kubernetes.io/ingress.class: nginx
spec:
  tls:
  - hosts:
    - my.domain.com
    secretName: tls-secret
  rules:
  - host: my.domain.com
    http:
      paths:
      - backend:
          service:
            name: new-service
            port:
              number: 80
        path: /someendpoint
        pathType: ImplementationSpecific
      - backend:
          service:
            name: new-service
            port:
              number: 80
        path: /
        pathType: Prefix

Hemanth Kumar · Accepted Answer · 2022-12-12T13:13:29.880

1

Ingress path matching can be enabled by setting the

nginx.ingress.kubernetes.io/use-regex annotation to true .

See the description of the use-regex annotation :

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: test-ingress
  annotations:
    nginx.ingress.kubernetes.io/use-regex: "true"
spec:
  ingressClassName: nginx
  rules:
  - host: test.com
    http:
      paths:
      - path: /foo/.*
        pathType: Prefix
        backend:
          service:
            name: test
            port:
              number: 80

Refer to this ingress path matching for more information on path priority

edited Dec 12 '22 at 13:13

answered Dec 12 '22 at 13:00

Hemanth Kumar

2,728
1
4
19

1

Thanks, I got it working following your suggestion, with minor tweaks. See solution in my updated question – IQn Dec 14 '22 at 14:34

score 0 · Answer 2 · answered Dec 12 '22 at 12:40

0

The solution is to use a regular expression (regex) to match all paths except /someendpoint.

answered Dec 12 '22 at 12:40

apan

353
3
11

I don't see this as an viable option, as we have about 50 others prefix patch in other ingresses and do not wish to update the regex and the other ingresses every time something changes or is added. – IQn Dec 12 '22 at 13:45

Kubernetes Ingress Exact not prioritized over Prefix

2 Answers2