Routing to ExternalName services doesn't work for ones created on the command line.

[outcast]

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Describe the bug Looks like I may have hit bug or doing something wrong. I am trying setup routing to an ExternalName service that I have created using the CLI and getting the following error: W0610 18:52:33.302089 1 controller.go:2133] Error retrieving endpoints for the service test-nginx: No port {0 80 } in service test-nginx

There is no port definition required for externalname services. Even the example show in the repo : https://github.com/nginxinc/kubernetes-ingress/tree/master/examples/externalname-services

To Reproduce Steps to reproduce the behavior:

1. Deploy the complete example from the examples folder
2. Create an externalname service via the cli in the same namespace as the ingress definition example: `kubectl -n default create service externalname foo --external-name=foo.example.com
3. Add a route to the ingress to the externalname
4. Try to go to the route and you will get a 503 error.

Expected behavior The route should work the same as if I had used a manifest to create the externalname service

Your environment AKS in Azure

• Version of the Ingress Controller - release version or a specific commit main branch from repo
• Version of Kubernetes Client Version: version.Info{Major:"1", Minor:"21", GitVersion:"v1.21.1", GitCommit:"5e58841cce77d4bc13713ad2b91fa0d961e69192", GitTreeState:"clean", BuildDate:"2021-05-12T14:18:45Z", GoVersion:"go1.16.4", Compiler:"gc", Platform:"linux/amd64"} Server Version: version.Info{Major:"1", Minor:"19", GitVersion:"v1.19.11", GitCommit:"c6a2f08fc4378c5381dd948d9ad9d1080e3e6b33", GitTreeState:"clean", BuildDate:"2021-05-13T17:14:18Z", GoVersion:"go1.15.12", Compiler:"gc", Platform:"linux/amd64"}
• Kubernetes platform (e.g. Mini-kube or GCP) AKS
• Using NGINX or NGINX Plus NGINX Plus

Additional context I have also submitted a F5 ticket as well.

https://my.f5.com/manage/s/case/5001T00001V0papQAB/routing-to-externalname-services-doesnt-work-for-ones-created-on-the-command-line

Aha! Link: https://nginx.aha.io/features/IC-236

[github-actions[bot]]

Hi @outcast thanks for reporting!

Be sure to check out the docs while you wait for a human to take a look at this :slightly_smiling_face:

Cheers!

[github-actions[bot]]

This issue is stale because it has been open 60 days with no activity. Remove stale label or comment or this will be closed in 7 days.

[outcast]

bump

[jasonwilliams14]

@outcast When using our externalName with NGINX Ingress Controller, NGINX Ingress controller requires that external name services do not have any selectors requires.

For example:

kind: Service
apiVersion: v1
metadata:
  name: my-service
spec:
  type: ExternalName
  externalName: my.service.example.com

When you create your externalName service using the imperative method like you did, it will automatically add selectors to the config, which will not work with our Ingress controller:

For example, externalname created imperatively:

kubectl create service externalname ext-test --external-name nginx.org -n nginx-ingress --dry-run=client -oyaml
apiVersion: v1
kind: Service
metadata:
  creationTimestamp: null
  labels:
    app: ext-test
  name: ext-test
  namespace: nginx-ingress
spec:
  externalName: nginx.org
  selector:
    app: ext-test
  type: ExternalName
status:
  loadBalancer: {}

Let us know if you have any questions.

[outcast]

Wouldn't this still be considered a bug since it breaks Kubernetes norms and should be accounted for in code?

[jasonwilliams14]

@outcast I would not classify this a bug. I would say it would be a feature request to have our externalName support selectors.

[outcast]

or ignore them? :P

[brianehlert]

IMHO - the outlier here is how command-line created objects behave. The assumptions that are made for you when you define objects using the command line. That said. There is an opportunity. However, the use of a selector does complicate the API interaction as it becomes a query instead of a direct path so that might complicate things.