How to expose traefik v2 dashboard in k3d/k3s via configuration? - kubernetes

Question

*Cross-posted to k3d github discussions, to a thread in Rancher forums, and to traefik's community discussion board
Tutorials from 2020 refer to editing the traefik configmap. Where did it go?
The traefik installation instructions refer to a couple of ways to expose the dashboard:
This works, but isn't persistent: Using a 1-time command kubectl -n kube-system port-forward $(kubectl -n kube-system get pods --selector "app.kubernetes.io/name=traefik" --output=name) 9000:9000
I cannot get this to work: Creating an "IngressRoute" yaml file and applying it to the cluster. This might be due to the Klipper LB and/or my ignorance.
No configmap in use by traefik deployment
For a 2-server, 2-agent cluster... kubectl -n kube-system describe deploy traefik does not show any configmap:
Volumes:
data:
Type: EmptyDir (a temporary directory that shares a pod's lifetime)
Medium:
SizeLimit: <unset>
tmp:
Type: EmptyDir (a temporary directory that shares a pod's lifetime)
Medium:
SizeLimit: <unset>
Priority Class Name: system-cluster-critical
No "traefik" configmap
And, kubectl get -n kube-system cm shows:
NAME DATA AGE
chart-content-traefik 0 28m
chart-content-traefik-crd 0 28m
chart-values-traefik 1 28m
chart-values-traefik-crd 0 28m
cluster-dns 2 28m
coredns 2 28m
extension-apiserver-authentication 6 28m
k3s 0 28m
k3s-etcd-snapshots 0 28m
kube-root-ca.crt 1 27m
local-path-config 4 28m
No configmap in use by traefik pods
Describing the pod doesn't turn up anything either. kubectl -n kube-system describe pod traefik-.... results in no configmap too.
Traefik ports in use, but not responding
However, I did see arguments to the traefik pod with ports in use:
--entryPoints.traefik.address=:9000/tcp
--entryPoints.web.address=:8000/tcp
--entryPoints.websecure.address=:8443/tcp
However, these ports are not exposed. So, I tried port-forward with kubectl port-forward pods/traefik-97b44b794-r9srz 9000:9000 8000:8000 8443:8443 -n kube-system --address 0.0.0.0, but when I curl -v localhost:9000 (or 8000 or 8443) and curl -v localhost:9000/dashboard, I get "404 Not Found".
After getting a terminal to traefik, I discovered the local ports that are open, but it seems nothing is responding:
/ $ netstat -lntu
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address Foreign Address State
tcp 0 0 :::8443 :::* LISTEN
tcp 0 0 :::8000 :::* LISTEN
tcp 0 0 :::9000 :::* LISTEN
/ $ wget localhost:9000
Connecting to localhost:9000 ([::1]:9000)
wget: server returned error: HTTP/1.1 404 Not Found
/ $ wget localhost:8000
Connecting to localhost:8000 ([::1]:8000)
wget: server returned error: HTTP/1.1 404 Not Found
/ $ wget localhost:8443
Connecting to localhost:8443 ([::1]:8443)
wget: server returned error: HTTP/1.1 404 Not Found
Versions
k3d version v4.4.7
k3s version v1.21.2-k3s1 (default)

Answer 1

I found a solution and hopefully someone find a better one soon
you need to control your k3s cluster from your pc and not to ssh into master node, so add /etc/rancher/k3s/k3s.yaml into your local ~/.kube/config (in order to port forward in last step into your pc)
now get your pod name as follows:
kubectl get pod -n kube-system
and seach for traefik-something-somethingElse
mine was traefik-97b44b794-bsvjn
now this part is needed from your local pc
kubectl port-forward traefik-97b44b794-bsvjn -n kube-system 9000:9000
get http://localhost:9000/dashboard/ in your favorite browser and don't forget the second slash
enjoy the dashboard
please note you have to enable the dashboard first in /var/lib/rancher/k3s/server/manifests/traefik.yaml by adding
dashboard:
enabled: true

Answer 2

Jakub's answer is pretty good. But one thing that is unfortunate about it is that if k3s restarts, the configs get reset. According to the k3s docs, if you create a custom file called /var/lib/rancher/k3s/server/manifests/traefik-config.yaml, k3s' traefik will automatically update with this new config and use its values. Here is what I have:
apiVersion: helm.cattle.io/v1
kind: HelmChartConfig
metadata:
name: traefik
namespace: kube-system
spec:
valuesContent: |-
dashboard:
enabled: true
ports:
traefik:
expose: true # this is not recommended in production deployments, but I want to be able to see my dashboard locally
logs:
access:
enabled: true
With this setup, you can skip the port-forwarding and just go to http://localhost:9000/dashboard/ directly!

Answer 3

for the current latest version of k3s (1.21.4):
according to traefik's installation guide (https://doc.traefik.io/traefik/getting-started/install-traefik/#exposing-the-traefik-dashboard), create dashboard.yaml with the proper CRD content, and run
kubectl apply -f dashboard.yaml
create DNS record or modify host file of the hostname - ip mapping for you set up in last step