kubens and kubectl ns

[Paul-Browne]

kubectl ns works as expected and returns a list of namespaces. However kubens gives the error

paulbrowne@A-FVFGD2H8Q05P ~ % kubens
error: could not list namespaces (is the cluster accessible?): failed to initialize k8s REST client: failed to initialize config: invalid configuration: unable to read certificate-authority my_cluster_name.k8s.local.crt for my_cluster_name.k8s.local due to open my_cluster_name.k8s.local.crt: no such file or directory

[dosubot]

Hi @Paul-Browne! I'm Dosu and I’m helping the kubectx team.

The error from kubens means it can't find the certificate-authority file referenced in your kubeconfig, so it fails to initialize the Kubernetes client. Unlike kubectl ns (which is an external plugin or alias and not part of this repo), kubens is strict: if the certificate file is missing or the path is wrong, it immediately throws an error and doesn't try to resolve or ignore it.

To fix this, check that the file my_cluster_name.k8s.local.crt exists at the path specified in your kubeconfig. If it's missing, update your kubeconfig to point to the correct location, or copy the certificate file to where it's expected. Also, compare your environment variables and PATH settings between the two commands—sometimes differences there can affect how files are resolved.

For more details on how kubens handles kubeconfig and errors, see the source code.

To reply, just mention @dosu.

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[ahmetb]

Does kubectl actually work? At any rate the error is basically saying the kubeconfig file you have is misconfigured. Maybe use absolute paths?

[cshiv]

I am getting a similar error , but this is happening only with the cluster created by K3s. I am digging more into it, but I am not sure what's happening.
This is the scenario

1. kubectx and kubens works on pretty much all the clusters created like EKS,GKE etc
2. When I create cluster with k3s, kubectx is working but kubens is not working. However kubectl get ns works .

I get the following error

 % kubens
error: could not list namespaces (is the cluster accessible?): failed to list namespaces from k8s API: Get "https://<API-Server>:6443/api/v1/namespaces?limit=500": dial tcp: lookup <API-Server> on <redacted>: no such host

% kubectl get po
No resources found in default namespace.

 % kubectl get ns
NAME              STATUS   AGE
default           Active   6m12s
kube-node-lease   Active   6m12s
kube-public       Active   6m12s
kube-system       Active   6m12s
metallb-system    Active   5m44s

I tried to open a proxy with kubectl proxy --port 8080

API % curl 127.0.0.1:8080/api/v1/namespaces fetches results .

API
% curl 127.0.0.1:8080/api/v1/namespaces?limit=500 throws up following error

% curl 127.0.0.1:8080/api/v1/namespaces?limit=500
zsh: no matches found: 127.0.0.1:8080/api/v1/namespaces?limit=500

However this behaviour is observed on other clusters too, Not sure where I should check

I am using kubens 0.9.4

~ % kubens --version
0.9.4

Kubeconfig looks something like this

apiVersion: v1
clusters:
- cluster:
    certificate-authority-data: <redacted>
    server: https://<redacted>:6443
  name: <redacted>
contexts:
- context:
    cluster:<redacted>
    user: <redacted>
  name: <redacted>
current-context: <redacted>
kind: Config
users:
- name: <redacted>
  user:
    client-certificate-data: <redacted>
    client-key-data: <redacted>

Looking forward for your inputs

[ahmetb]

Can you attach the "kubectl get ns -v7" output please? Also what version of apiserver is this cluster running.

Assuming k3s doesn't distribute its own kubectl, this should be working.

[cshiv]

Apologies for delay in getting back

% kubectl get ns -v7
I1013 21:06:15.425768   18071 loader.go:402] Config loaded from file:  /Users/<redacted>/.kube/config
I1013 21:06:15.426111   18071 envvar.go:172] "Feature gate default state" feature="ClientsPreferCBOR" enabled=false
I1013 21:06:15.426118   18071 envvar.go:172] "Feature gate default state" feature="InformerResourceVersion" enabled=false
I1013 21:06:15.426121   18071 envvar.go:172] "Feature gate default state" feature="InOrderInformers" enabled=true
I1013 21:06:15.426123   18071 envvar.go:172] "Feature gate default state" feature="WatchListClient" enabled=false
I1013 21:06:15.426126   18071 envvar.go:172] "Feature gate default state" feature="ClientsAllowCBOR" enabled=false
I1013 21:06:15.429769   18071 round_trippers.go:527] "Request" verb="GET" url="https://<redacted>:6443/api/v1/namespaces?limit=500" headers=<
	Accept: application/json;as=Table;v=v1;g=meta.k8s.io,application/json;as=Table;v=v1beta1;g=meta.k8s.io,application/json
	User-Agent: kubectl/v1.33.3 (darwin/arm64) kubernetes/80779bd
 >
I1013 21:06:16.470304   18071 round_trippers.go:632] "Response" status="200 OK" milliseconds=1040
NAME              STATUS   AGE
default           Active   11d
kube-node-lease   Active   11d
kube-public       Active   11d
kube-system       Active   11d
metallb-system    Active   11d

Version:

% kubectl version
Client Version: v1.33.3
Kustomize Version: v5.6.0
Server Version: v1.34.1+k3s1