Add documentation for kubernetes/helm (#2743)

Co-authored-by: jose <[email protected]>

docs/guide/installation/08_kubernetes.md

@@ -0,0 +1,83 @@
+---
+next: ../configuration/
+---
+
+# Kubernetes
+
+These instructions explain how to run Zigbee2MQTT on k8s clusters through the use of the helm chart.
+
+# Values - Configuration
+
+Regardless of the method of installation chosen helm cli, flux/argo CD, first review the values.yaml file and choose the
+configuration required for you.
+The Zigbee2MQTT config section in the values.yaml is a 1:1 mapping of the usual config file, it simply is created on a configmap
+during the helm release creation. If you don't provide any additional values, sensible defaults are used in the deployment.
+
+If you are planning to use an usb adapter directly plugged into a node of the cluster, most likely you need to
+specify a `.values.statefulset.nodeSelector` so the pods are scheduled in the right node.
+
+By default, storage is not enabled, which is great for testing.
+If you just want to use dynamic volume provisioning, just configure the `statefulset.storage.storageClassName`.
+Persisting the volumes across installations, or you want to reuse existing data, you can leverage the options
+in `statefulset.storage` either providing a `volumeName` or selectors for volumes. Those fields get injected
+into the statefulSet persistentVolumeClaim which can link to existing volumes.
+
+## helm
+
+To install the chart manually using helm, first you need to add your the helm repository to your local helm installation:
+
+```bash
+helm repo add zigbee2mqtt  https://charts.zigbee2mqtt.io
+```
+
+Load the charts from the repository:
+
+```bash
+helm repo update
+```
+
+Install the helm chart using the values of your choice (`myvalues.yaml` in the snipet below):
+
+```bash
+helm install -f myvalues.yaml zigbee2mqtt zigbee2mqtt/zigbee2mqtt
+```
+
+## flux
+
+If you are using a gitops approach to manage your cluster, you can use the flux CRDs to create and manage the releases.
+
+The first step is to add to your repository the helm repository of zigbee2mqtt:
+
+```yaml
+apiVersion: source.toolkit.fluxcd.io/v1beta2
+kind: HelmRepository
+metadata:
+    name: zigbee2mqtt
+    namespace: flux-system
+spec:
+    interval: 10m
+    url: https://charts.zigbee2mqtt.io/index
+```
+
+Then create a Helm release:
+
+```yaml
+apiVersion: helm.toolkit.fluxcd.io/v2beta2
+kind: HelmRelease
+metadata:
+    name: zigbee2mqtt
+    namespace: flux-system
+spec:
+    interval: 5m
+    targetNamespace: zigbee2mqtt
+    chart:
+        spec:
+            chart: zigbee2mqtt
+            version: '1.37.1'
+            sourceRef:
+                kind: HelmRepository
+                name: zigbee2mqtt
+                namespace: flux-system
+            interval: 10m
+    values: ... your settings
+```

docs/guide/installation/README.md

@@ -12,6 +12,7 @@ Zigbee2MQTT was written in Node.js and runs almost on every platform with afford
 - [Windows](./05_windows.md)
 - [FreeBSD jail](./06_freebsd_jail.md)
 - [Python virtual-environment](./07_python_virtual_environment.md)
+- [Kubernetes](./08_kubernetes.md)
 
 ## Optional