Exposing a TCP port out of cluster in Kubernetes using nginx-Ingress
Question
So I have setup my application on Google cloud using Kubernetes. I have a Pod which I want to expose out of the cluster that expects TCP requests.
I came to know that this is possible via ingress-nginx and researched about it. As mentioned in the docs here , it can be done by setting up a configMap like below:
apiVersion: v1
kind: ConfigMap
metadata:
name: tcp-configmap-example
data:
9000: "default/my-service-name:7051
, but it's full usage is not clearly described nor I could find a complete example in the docs properly.
I have installed ingress-nginx as mentioned in the Installation Guide but I am unsure what the next steps are to expose my Pod.
Extra Info
- The port in the Pod that I want to expose out of cluster is
7051 - I have a NodePort Service that targets my Pod's port that can be used with Ingress to expose.
2 answers
solution1
4 2019-10-27 14:11:26
So, in order to achieve this you can do this:
- First create the configMap that you added to the post.
apiVersion: v1
kind: ConfigMap
metadata:
name: tcp-configmap-example
data:
9000: "default/my-service-name:7051
Then edit your nginx-ingress-controller deployment by adding this flag to container args like below:
... containers: - name: nginx-ingress-controller image: "quay.io/kubernetes-ingress-controller/nginx-ingress-controller:0.26.1" imagePullPolicy: "IfNotPresent" args: - /nginx-ingress-controller - --default-backend-service=nginx-ingress/nginx-ingress-default-backend - --election-id=ingress-controller-leader - --ingress-class=nginx - --configmap=nginx-ingress/nginx-ingress-controller - --tcp-services-configmap=default/tcp-configmap-example ...Edit LoadBalancer service by adding port to your LoadBalancer
... ports: - name: http port: 80 protocol: TCP targetPort: http - name: https port: 443 protocol: TCP targetPort: https - name: some-service-port port: 7051 protocol: TCP
Hope it helps!
solution2
0 2021-09-24 06:25:12
If you are installing with helm there is a way to expose tcp ports by setting values.
# add helm repo
helm repo add ingress-nginx https://kubernetes.github.io/ingress-nginx
helm repo update
helm show values ingress-nginx/ingress-nginx will show the values.yaml file for reference, there are two dictionaries for exposing ports: tcp and udp :
# TCP service key:value pairs
# Ref: https://github.com/kubernetes/ingress-nginx/blob/main/docs/user-guide/exposing-tcp-udp-services.md
##
tcp: {}
# 8080: "default/example-tcp-svc:9000"
# UDP service key:value pairs
# Ref: https://github.com/kubernetes/ingress-nginx/blob/main/docs/user-guide/exposing-tcp-udp-services.md
##
udp: {}
# 53: "kube-system/kube-dns:53"
To set the values from command line:
# set `tcp` dictionary in values (other `helm install` options omitted, only left options regarding to exposing tcp ports)
helm install ingress-nginx ingress-nginx/ingress-nginx --set tcp.12345=some-namespace/some-service:80
solution3
-2 2018-10-30 10:51:20
Inside Google Cloud Platform you can use type: LoadBalancer in order to expose your service outside the cluster. You can see example here Exposing Applications using Services .
Here is a quick example:
$ kubectl run hello --image=test/hello-world
deployment "hello" created
$ kubectl expose deployment hello --port=8080 --type=LoadBalancer
service "hello" exposed
$ kubectl get service
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
hello LoadBalancer 10.11.251.34 35.192.25.112 8080:33107/TCP 2m
$ curl 35.192.25.112:8080
<html><head><title>hello world</title></head><body>hello world!</body></html>
Also you can follow the instructions inside Kubernetes documentation Exposing an External IP Address to Access an Application in a Cluster
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