nut_webgui on kubernetes

[linux24365]

Good Morning,
Sorry to bother you, but I need some help / guidance. I am trying to setup nut_webgui on Kubernetes using the example you provided. I am just wondering what would be the port to access the http page. ( I tried 80 , 9000 without success) . Either I get "no server available " or "no page found". The port 3493 conncetion to my external network UPS tool server seems to work according to the pod logs
Thanks

[SuperioOne]

Default port for web UI is 9000, unless PORT environment variable has a different value.

Do you have any ingress or service configuration to expose nut_webgui's HTTP port? Normally, I didn't include them in the example since there are too many options.

Most basic one looks something like this, but you still need an ingress config, or use different service type.

apiVersion: v1
kind: Service
metadata:
  name: nutwebgui-service
spec:
  type: ClusterIP
  selector:
    app: nutweb-pod
  ports:
  - port: 80
    targetPort: 9000

For troubleshooting, I would use the kubectl port-forward command to see if Pod is accessible via service or deployment.

# Exposes deployment port (9000) on localhost:9000
kubectl port-forward deployments/nutweb-deployment 9000:9000

# Exposes service port (80) on localhost:9000
kubectl port-forward services/nutwebgui-service 80:9000

Also, feel free to ask anytime 👍

[linux24365]

Hi,

Thank you for your response. Now I get it, everything works fine. I might have gotten confused because of the EndPointSlice. It's the first time I came across this config and I didn't know where to put it. So I created, as you suggested a second service along side just for the webgui and now all seems to be comprehensive. .

[SuperioOne]

I'm glad it's working now.

Might have gotten confused because of the EndPointSlice.

Its kinda confusing at first glance, especially since it has its own service. I should actually improve the examples for better clarity 😅 .

[linux24365]

This brings me to the question, what was/is the benefit of of EndPointslices. I am running a 6 nodes K3s cluster, which is ,from what I read, not really the target for EndPointSlices

[SuperioOne]

It turns a NUT server endpoint into Kubernetes Service with DNS record (nut-service). It also allows some topology-aware routing for people with very specific network requirements, which makes it little bit more flexible.

Other than these benefits, you can achieve the similar thing with CoreDNS, ExternalName Service (which only supports DNS names), or you can simply ignore all complexity and use NUT server address directly on UPSD_ADDR.

Extra Note:
You often see EndpointSlices mentioned in multi-zone huge deployments, but they are actually pretty common resource type. Almost every Service create their own endpoint slice under the hood regardless of cluster size.