How to use nginx ingress to route traffic based on port

Question

I'm currently working on deploying ELK stack on kubernetes cluster, i was successfully able to use ClusterIP service and nginx-ingress on minikube to route inbound http traffic to kibana (5601 port), need inputs on how i can route traffic based on inbound port rather than path?

Using below Ingress object declaration, i was successfully able to connect to my kibana deployment, but how can i access other tools stack exposed on different ports (9200, 5044, 9600)?

---
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  annotations:
    kubernetes.io/ingress.class: nginx
  name: ingress-service
spec:
  rules:
  - http:
      paths:
      - path: /
        backend:
          serviceName: kibana-service
          servicePort: 5601

CUrl'ing minikube ip on default 80 port returns valid response

# curl http://<minikube-ip>/api/status
{"name":"kibana",....}

Note: i would not want to use NodePort, but would like to know if nodeport is the only way we can achieve the above?

Answer 1

As you already have minikube and minikube ingress addon enabled:

$ minikube addons list | grep ingress
| ingress                     | minikube | enabled ✅   |
| ingress-dns                 | minikube | enabled ✅   |

Just as reminder:

targetPort: is the port the container accepts traffic on (port where application runs inside the pod).

port: is the abstracted Service port, which can be any port other pods use to access the Service.

Please keep in mind that if your container will not be listening port specified in targetPort you will not be able to connect to the pod. Also remember about firewall configuration to allow traffic.

As for example I've used this yamls:

apiVersion: v1
kind: Service
metadata:
  name: service-one
spec:
  selector:
    key: application-1
  ports:
    - port: 81
      targetPort: 8080
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: deployment-1
spec:
  replicas: 1
  selector:
    matchLabels:
      key: application-1
  template:
    metadata:
      labels:
        key: application-1
    spec:
      containers:
      - name: hello1
        image: gcr.io/google-samples/hello-app:1.0
        imagePullPolicy: IfNotPresent
        ports:
        - containerPort: 8080
---
apiVersion: v1
kind: Service
metadata:
  name: service-two
spec:
  selector:
    key: application-2
  ports:
    - port: 82
      targetPort: 8080
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: deployment-2
spec:
  replicas: 1
  selector:
    matchLabels:
      key: application-2
  template:
    metadata:
      labels:
        key: application-2
    spec:
      containers:
      - name: hello2
        image: gcr.io/google-samples/hello-app:2.0
        imagePullPolicy: IfNotPresent
        ports:
        - containerPort: 8080
---
apiVersion: networking.k8s.io/v1beta1
kind: Ingress
metadata:
  name: ingress
  annotations:
    kubernetes.io/ingress.class: nginx
spec:
  rules:
  - http:
      paths:
      - path: /hello
        backend:
          serviceName: service-one
          servicePort: 81
      - path: /hello2
        backend:
          serviceName: service-two
          servicePort: 82

service/service-one created
deployment.apps/deployment-1 created
service/service-two created
deployment.apps/deployment-2 created
Warning: networking.k8s.io/v1beta1 Ingress is deprecated in v1.19+, unavailable in v1.22+; use networking.k8s.io/v1 Ingress
ingress.networking.k8s.io/ingress created

Warning: networking.k8s.io/v1beta1 Ingress is deprecated in v1.19+, unavailable in v1.22+; use networking.k8s.io/v1 Ingress

Please keep in mind that soon Minikube will change apiVersion as per warning above.

Below output of this configuration:

$ curl http://172.17.0.3/hello
Hello, world!
Version: 1.0.0
Hostname: deployment-1-77ddb77d56-2l4cp
minikube-ubuntu18:~$ curl http://172.17.0.3/hello2
Hello, world!
Version: 2.0.0
Hostname: deployment-2-fb984955c-5dvbx

You could use:

      paths:
      - path: /elasticsearch
        backend:
          serviceName: elasticsearch-service
          servicePort: 100
      - path: /anotherservice
        backend:
          serviceName: another-service
          servicePort: 101

Where service would looks like:

  name: elasticsearch-service
  ...
  ports:
    - port: 100
      targetPort: 9200
  ---
  name: another-service
  ...
  ports:
    - port: 101
      targetPort: 5044

However, if you would need more advanced path configuration you can also use rewrite. Also you can use default backend to redirect to specific service.

More information about accessing Minikube you can find in Minikube documentation.

Is it what you were looking for or something different?