mqtt

This is a simple helm chart to install an Eclipse mosquitto based MQTT service in your K3S kubernetes cluster.

Prerequisites

Currently the chart is made for a K3S kubernetes cluster with the integrated traefik ingress and currently I have no intention to develop this chart to a general purpose kubernetes cluster installation with other ingress controllers. Please let me know, if you feel the need, that this should be done.

Installation

Add traefik entry point

To expose your MQTT service to clients outside the cluster, you must add an entry point to the traefik ingress configuration.

To do this, you have to take the following manifest:

apiVersion: helm.cattle.io/v1
kind: HelmChartConfig
metadata:
  name: traefik
  namespace: kube-system
spec:
  valuesContent: |-
    ports:
        mqtt:
            port: 1883
            expose: true
            protocol: TCP

And add it to the server installation. To do this:

Copy the file to the directory /var/lib/rancher/k3s/server/manifests
Restart the server, e.g. with systemctl restart k3s.service, on a systemd based system.

Configure the chart

The chart comes with a decent set of default values for configuring the mosquitto image. See the comments in the default Values file for further information or documentation of the configuration values below.

Listener port

Sets the port, mosquitto listens on. This value is optional. If not set, the default port 1883 will be used.

Please have in mind that this setting impacts not only the port the pod is listening on, but also the service manifest and the ingress route created to expose the port outside the cluster. So if you are using another than the default port 1883, please also adapt the trafik entry point accordingly.

configuration:
    listener:
        port: 1883

Listener address

The host interface/address/socket mosquitto listens on. This value is optional. If not set, mosquitto listens on all interfaces. See https://mosquitto.org/man/mosquitto-conf-5.html for further information.

configuration:
    listener:
        address: "0.0.0.0"

Enable persistence

With the default configuration, the mosquitto service does not use persistence. If you need to use the mosquitto MQTT broker with persistence, you can simply enable it.

Enabling persitence results in creating manifests for a PersistentVolumeClaim and mouting a volume matching the claim in the started pod.

configuration:
    persistence:
        enabled: true

Select the storage class

When using the mosquitto MQTT broker with persistence, you can choose the storage class provider. If not set, the k3s default storage class provider local-path will be used. See the k3s documentation on https://rancher.com/docs/k3s/latest/en/storage/ on how to install and use other storage class providers.

configuration:
    persistence:
        enabled: true
        storageClassName: local-path

Set the persistence volumes size

When using the mosquitto MQTT broker with persistence, you can either use the default size of the volume used to back the persistence database with 256Mi or you can set the size with the volume size value of your choice.

configuration:
    persistence:
        enabled: true
        size: 256Mi

FSeidinger/mqtt