In the context of developing apps on Kubernetes it is often useful to quickly access a service from your local environment without exposing it using, for example, a load balancer or an ingress resource. In this case you can use port forwarding.
Let’s create an app consisting of a deployment and a service called simpleservice, serving on port 80:
kubectl apply -f https://raw.githubusercontent.com/openshift-evangelists/kbe/main/specs/pf/app.yaml
Let’s say we want to access the simpleservice service from the local environment, say, your laptop, on port 8080. So we forward the traffic as follows:
kubectl port-forward service/simpleservice 8080:80
Forwarding from 127.0.0.1:8080 -> 9876
Forwarding from [::1]:8080 -> 9876
We can see from above that the traffic gets eventually routed through the service to the pod serving on port 9876.
Now we can invoke the service locally like so (using a separate terminal session):
curl localhost:8080/info
{"host": "localhost:8080", "version": "0.5.0", "from": "127.0.0.1"}
Remember that port forwarding is not meant for production traffic but for development and experimentation.
You can remove the simpleservice with
kubectl delete service/simpleservice
kubectl delete deployment sise-deploy