how to make already exposed service not to be exposed? - kubernetes

Question

I deployed a (LoadBalancer) service for a pod on my minikube cluster, then exposed it via minikube service [my_service] command. Now I tried to "turn off the exposure" but couldn't find any way to do this, except deleting it what I would like to avoid. Is it possible to just turn off the exposure, not deleting (and redeploying) the existing already exposed service?

Answer 1

Background
In Kubernetes documentation regarding ServiceTypes, you can find information that if you want to expose your cluster outside you have to use NodePort or LoadBalancer.
If you want to keep your service/application in cluster, you should use ClusterIP:
Exposes the Service on a cluster-internal IP. Choosing this value makes the Service only reachable from within the cluster. This is the default ServiceType.
Depends on your version, you can edit it or use workaround. For example in K8s 1.16 you won't be able as some errors might occurs.
$ kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.8.0.1 <none> 443/TCP 3d20h
my-nginx LoadBalancer 10.8.14.224 34.121.77.108 80:32039/TCP 3m16s
$ kubectl patch service my-nginx -p '{"spec":{"type":"ClusterIP"}}'
The Service "my-nginx" is invalid: spec.ports[0].nodePort: Forbidden: may not be used when `type` is 'ClusterIP'
Solutions
However as you are using Minikube so I guess you are using newer version (1.20), so you can change it using:
kubectl edit
kubectl edit svc <yourSvcName> and change type to ClusterIP.
It will open Vi editor, where you can change spec.type to ClusterIP or just remove it as default type for Kubernetes service is ClusterIP so if it won't be specified, Kubernetes will automatically use ClusterIP.
$ kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 25s
my-nginx LoadBalancer 10.107.129.201 <pending> 80:30173/TCP 8s
minikube-new:~$ kubectl edit svc my-nginx
service/my-nginx edited
sekreta#minikube-new:~$ kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 46s
my-nginx ClusterIP 10.107.129.201 <none> 80/TCP 29s
kubectl patch
$ kubectl patch service <yourServiceName> -p '{"spec":{"type":"ClusterIP"}}'
$ kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 10m
my-nginx LoadBalancer 10.107.129.201 <pending> 80:30456/TCP 2m
minikube-new:~$ kubectl patch service my-nginx -p '{"spec":{"type":"ClusterIP"}}'
service/my-nginx patched
minikube-new:~$ kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 10m
my-nginx ClusterIP 10.107.129.201 <none> 80/TCP 3m
kubectl apply
You can edit your Yaml and remove spec.type or have 2 Yamls with ClusterIP and LoadBalancer and switch them depends on your needs.
$ kubectl apply -f svc.yaml
service/my-nginx configured
minikube-new:~$ kubectl get svc
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE
kubernetes ClusterIP 10.96.0.1 <none> 443/TCP 22m
my-nginx ClusterIP 10.111.237.133 <none> 80/TCP 16s
Use some 3rd party software to make changes in your cluster like Helm and using templates.