add k3s traefik writeup

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rskntroot
2024-06-08 06:48:24 +00:00
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# K3S Traefik Setup
## Brief
Enabling internal access to dashboard and metrics for traefik ingress controller in k3s kubernetes cluster
- by `rskntroot` on `2024-07-01`
## Assumptions
```
$ k3s --version
k3s version v1.29.5+k3s1 (4e53a323)
go version go1.21.9
```
```
$ kubectl version
Client Version: v1.29.5+k3s1
Kustomize Version: v5.0.4-0.20230601165947-6ce0bf390ce3
Server Version: v1.29.5+k3s1
```
## Traefik Dashboards
*Note: `Traefik Dashboards` refers to both traefik dashboard and prometheus*
### Preparation
Enable `internal`+`.your.domain.com` in non-public DNS
- (alt) edit the `hosts` file on your admin to point the desired k3s host IP
On host with `kubectl` access:
```
export DOMAIN=your.domain.com
```
*Note: This example does not currently include authentication and exposing these dashboards is a security risk.*
### Update Manifest
Add the following to `spec.valuesContent` section of `/var/lib/rancher/k3s/server/manifests/traefik.yaml`
```
dashboard:
enabled: true
metrics:
prometheus: true
```
Example:
```
spec:
chart: https://%{KUBERNETES_API}%/static/charts/traefik-25.0.3+up25.0.0.tgz
set:
global.systemDefaultRegistry: ""
valuesContent: |-
deployment:
podAnnotations:
prometheus.io/port: "8082"
prometheus.io/scrape: "true"
dashboard:
enabled: true
metrics:
prometheus: true
```
### Restart Ingress Controller
```
kubectl -n kube-system scale deployment traefik --replicas=0
kubectl -n kube-system get deployment traefik
```
```
kubectl -n kube-system scale deployment traefik --replicas=1
```
Example: (`kubectls`?! see `#shortcuts`)
```
$ kubectls scale deployment traefik --replicas=0
deployment.apps/traefik scaled
$ kubectls get deployment traefik
NAME READY UP-TO-DATE AVAILABLE AGE
traefik 0/0 0 0 3d1h
$ kubectls scale deployment traefik --replicas=1
deployment.apps/traefik scaled
```
### Create Resource Definition YAML
Save the following to `traefik-dashboard.yml` in your workspace.
```
apiVersion: v1
kind: Service
metadata:
name: traefik-dashboard
namespace: kube-system
labels:
app.kubernetes.io/instance: traefik
app.kubernetes.io/name: traefik-dashboard
spec:
type: ClusterIP
ports:
- name: traefik
port: 9000
targetPort: 9000
protocol: TCP
selector:
app.kubernetes.io/instance: traefik-kube-system
app.kubernetes.io/name: traefik
---
apiVersion: v1
kind: Service
metadata:
name: traefik-metrics
namespace: kube-system
labels:
app.kubernetes.io/instance: traefik
app.kubernetes.io/name: traefik-metrics
spec:
type: ClusterIP
ports:
- name: traefik
port: 9100
targetPort: 9100
protocol: TCP
selector:
app.kubernetes.io/instance: traefik-kube-system
app.kubernetes.io/name: traefik
---
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
name: traefik-ingress
namespace: kube-system
annotations:
spec.ingressClassName: traefik
spec:
rules:
- host: internal.${DOMAIN}
http:
paths:
- path: /
pathType: Prefix
backend:
service:
name: traefik-dashboard
port:
number: 9000
- path: /metrics
pathType: Prefix
backend:
service:
name: traefik-metrics
port:
number: 9100
```
If you don't want `traefik-metrics` simply do not include the service definition and remove the `- path: metrics` section from the ingress definition.
### Create Service & Ingress Resources
[envsubst](https://www.gnu.org/software/gettext/manual/html_node/envsubst-Invocation.html) - `envsusbst` enables code-reuse by providing environment variable substituion as demonstrated below.
```
envsubst < traefik-dashboard.yml | kubectl apply -f -
```
Example:
```
$ envsubst < traefik-dashboards.yml | kubectl apply -f -
service/traefik-dashboard created
service/traefik-metrics created
ingress.networking.k8s.io/traefik-ingress created
$ kubectls get svc | grep traefik-
traefik-dashboard ClusterIP 10.43.157.54 <none> 9000/TCP 25s
traefik-metrics ClusterIP 10.43.189.128 <none> 9100/TCP 25s
```
### Access Dashboards
That's it. You should now be able to access the Traefik Ingress Controller Dashboard and metrics remotely.
Don't forget to include the appropriate uri paths:
- `internal.your.domain.com/dashboard/` for `Traefik Dashboard` *(Note: just `/dashboard` will not work.)*
- `internal.your.domain.com/metrics` for `Traefik Metrics`
### Disable Dashboards
```
envsubst < traefik-dashboard.yml | kubectl delete -f -
```
Example:
```
envsubst < traefik-dashboards.yml | kubectl delete -f -
service "traefik-dashboard" deleted
service "traefik-metrics" deleted
ingress.networking.k8s.io "traefik-ingress" deleted
```
## Shortcuts
### alias kubectls
*Note: kubectl-completion will not work for `kubectls`*
```
echo 'alias kubectls="kubectl -n kube-system"' >> ~/.bashrc
source ~/.bashrc
```
Example:
```
$ echo 'alias kubectls="kubectl -n kube-system"' >> ~/.bashrc
$ source ~/.bashrc
$ kubectls get deployments
NAME READY UP-TO-DATE AVAILABLE AGE
coredns 1/1 1 1 3d2h
local-path-provisioner 1/1 1 1 3d2h
metrics-server 1/1 1 1 3d2h
traefik 1/1 1 1 3d2h
```
(alt) use `skubectl` or `kubesctl` as the alias instead. comparisons:
- `skubectl` means you can hit `[up-arrow]` `[ctrl]+[a]` `[s]` `[enter]` when you inevitably forget to include `-n kube-system`
- `kubectls` just adds `[alt]+[right-arrow]` to the above
- `kubesctl` makes sense because all of these are really kube-system-ctl, but that adds 4x `[right-arrow]`, ewww.
## References
- [https://docs.k3s.io](https://docs.k3s.io)
- [https://k3s.rocks/traefik-dashboard/](https://k3s.rocks/traefik-dashboard/)
- [https://doc.traefik.io/traefik/v2.10/](https://doc.traefik.io/traefik/v2.10/)

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@@ -12,4 +12,5 @@ Rskio
./docs/system_on_chip.md ./docs/system_on_chip.md
./docs/network_attached_storage.md ./docs/network_attached_storage.md
./docs/k3s_traefik_setup.md