ingress ip is providing expected result but host returns 404 http not found

Ingress.yaml

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: helloworld-ing
  annotations:
    nginx.ingress.kubernetes.io/ssl-redirect: "false" 
    nginx.ingress.kubernetes.io/use-regex: "true" 
    nginx.ingress.kubernetes.io/rewrite-target: /$2
spec:
  defaultBackend:
    service:
      name: helloworld-svc
      port:
        number: 8080
  ingressClassName: nginx
  tls:
    - hosts:
        - helloworld.dev.com
      secretName: ingress-tls-csi
  rules:
    - host: helloworld.dev.com
      http:
        paths:
          - path: /helloworld
            pathType: Prefix
            backend:
              service:
                name: helloworld-svc
                port:
                  number: 8080

Ingress Ip was not working earlier but adding default backend resolved that issue. I believe this can be the issue that its not going past backend and not even reaching rules.

I do not see warning/errors in ingress logs but If I remove default backend I can not even access app using ingress IP.

I am not sure what I am missing in my ingress configuration.

I am trying same path for url and Ip -

Curl http://10.110.45.61/helloworld/service/result

Curl http://helloworld.dev.com/helloworld/service/result

I am happy to provide more information if required.

CodePudding user response：

Hello, Hope you'are enjoying your Kubernetes journey !

So This is what I have tested for a first try (i havent tested tls now): First I have setup a kind cluster locally with this configuration (info here: https://kind.sigs.k8s.io/docs/user/quick-start/):

kind: Cluster
apiVersion: kind.x-k8s.io/v1alpha4
name: so-cluster-1
nodes:
- role: control-plane
  image: kindest/node:v1.23.5
- role: control-plane
  image: kindest/node:v1.23.5
- role: control-plane
  image: kindest/node:v1.23.5
- role: worker
  image: kindest/node:v1.23.5
- role: worker
  image: kindest/node:v1.23.5
- role: worker
  image: kindest/node:v1.23.5

after this I create my cluster with this command:

kind create cluster --config=config.yaml

Next, i have created a test namespace (manifest obtained with: kubectl create ns so-tests -o yaml --dry-run):

apiVersion: v1
kind: Namespace
metadata:
  name: so-tests

then I created this vanilla nginx deployment and exposed it with a service, here is the config (manifest from here https://kubernetes.io/docs/concepts/workloads/controllers/deployment/#creating-a-deployment):

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx
        ports:
        - containerPort: 80

same with the pod (manifest from obtained with: k expose deployment nginx-deployment --dry-run -o yaml ):

apiVersion: v1
kind: Service
metadata:
  creationTimestamp: null
  labels:
    app: nginx
  name: nginx-deployment
spec:
  ports:
  - port: 80
    protocol: TCP
    targetPort: 80
  selector:
    app: nginx

after applying every manifests to my cluster and checked if my pods were running, I made sure that i could access my nginx pod web homepage by running:

kubectl port-forward pod/nginx-deployment-74d589986c-c85r9 8080:80 #checked on localhost:8080 and it was succesful

I've done the same against the service to make sure that it was correctly redirecting the traffic to the pod:

k port-forward service/nginx-deployment 8080:80 #checked on localhost:8080 and it was succesful

When I was sure that my workload was correctly running and accessible, I installed nginx ingress controller (from here: https://kubernetes.github.io/ingress-nginx/deploy/) with this command:

helm upgrade --install ingress-nginx ingress-nginx \
  --repo https://kubernetes.github.io/ingress-nginx \
  --namespace ingress-nginx --create-namespace

Then I created the ingress k8s resource, here is the config (obtained by running: k create ingress demo-localhost --class=nginx --rule="demo.localdev.me/*=demo:80" and by replacing the service.name by the name of my service.):

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  creationTimestamp: null
  name: demo-localhost
spec:
  ingressClassName: nginx
  rules:
  - host: demo.localdev.me
    http:
      paths:
      - backend:
          service:
            name: nginx-deployment
            port:
              number: 80
        path: /
        pathType: Prefix

Then to check if my ingress was corretly redirecting the traffic i ran:

kubectl port-forward --namespace=ingress-nginx service/ingress-nginx-controller 8080:80 #I also tested this on my browser localhost:8080

And guess what? -> 404 not found.

so, I decided to replace the name "demo.localdev.me" by "localhost" and it worked, here is the conf:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: demo-localhost
spec:
  ingressClassName: nginx
  rules:
  - host: localhost #demo.localdev.me
    http:
      paths:
      - backend:
          service:
            name: nginx-deployment
            port:
              number: 80
        path: /
        pathType: Prefix

I went to my C:\Windows\System32\drivers\etc\hosts file on windows (equivalent to /etc/hosts on linux, or equivalent to your DNS serveur in enterprise) to check if it was a dns issue, i added this line:

127.0.0.1       demo.localdev.me

and it worked as expected. (make sure to clear you browser cache when playing with /etc/hosts file or to use private navigation to get accurate resulsts)

So, you can do some testing: make sure that:

1. your path is correctly reachable (you can do the testing with kubectl port-forward, as i have done before)
2. you do have the correct entry in dns that redirects the traffic to your nginx service (not your application pod service)
3. you do not have a firewall that is blocking your ports
4. the tls configuration is working properly (try with and without)

If you have more information to share with us, feel free, i'll be happy to help you !

Have a nice day man !