chore: imported knowledge from the private kb, moved examples to the correct section

examples/kubernetes/grafana on k8s using helm.md

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+# Grafana on Kubernetes using Helm
+
+Installation:
+
+1. add the repository:
+
+   ```sh
+   helm repo add grafana https://grafana.github.io/helm-charts
+   helm repo update
+   ```
+
+1. install the release:
+
+   ```sh
+   helm upgrade --install --namespace monitoring --create-namespace grafana grafana/grafana
+   ```
+
+Get the admin user's password:
+
+```sh
+kubectl get secret --namespace monitoring grafana -o jsonpath="{.data.admin-password}" | base64 --decode ; echo
+```
+
+The Grafana server can be accessed via port 80 on `grafana.monitoring.svc.cluster.local` from within the cluster.  
+To get the external URL:
+
+```sh
+export POD_NAME=$(kubectl get pods --namespace monitoring -l "app.kubernetes.io/name=grafana,app.kubernetes.io/instance=grafana" -o jsonpath="{.items[0].metadata.name}")
+kubectl --namespace monitoring port-forward "${POD_NAME}" 3000
+```
+
+Clean up:
+
+```sh
+helm delete --namespace monitoring grafana
+kubectl delete namespace --ignore-not-found monitoring
+```
+
+Access a Prometheus instance in the same namespace using `http://prometheus-server`
+
+Get the default values from the updated chart
+
+```sh
+helm inspect values grafana/grafana > "$(git rev-parse --show-toplevel)/kubernetes/helm/grafana/values.yaml"
+```
+
+## Gotchas
+
+Useful dashboards:
+
+- `3662`: prometheus 2.0 overview
+- `6417`: kubernetes cluster (prometheus)
+- `9632`: nextcloud
+
+## Further readings
+
+- Official [helm chart]
+- [Set up prometheus and ingress on kubernetes]
+
+[helm chart]: https://github.com/grafana/helm-charts/tree/main/charts/grafana
+[set up prometheus and ingress on kubernetes]: https://blog.gojekengineering.com/diy-how-to-set-up-prometheus-and-ingress-on-kubernetes-d395248e2ba