MQTT - Broker in Docker

Diese Seite gibt es auch in Deutsch

MQTT (Message Queuing Telemetry Transport) is an open network protocol for transmitting messages between devices. An MQTT broker, like the open source Mosquitto server, is a simple solution to receive data from SmartHome devices or to control them .As an example, I use MQTT with an ESP32 microcontroller to have it send values to the MQTT broker, which can be retrieved via the MQTT integration in HomeAssistant. In addition, I use the MQTTBroker to communicate my Zigbee devices via Zigbee2MQT, see: Home-Assistant Docker Conbee 2 and Zigbee2MQTT / deCONZ 

Docker Basics

Docker allows applications to be launched by command in a so-called container.
A container is an isolated environment independent of the operating system (OS):
When a container is first launched, Docker independently loads all the necessary sources
from the internet.
Docker can be installed on Windows, macOS or an Linux Distribution

Those who have Docker and Docker Compose installed on their system can start the Mosquitto MQTT broker after creating the following file, for now without the config folder so that we can assign a password for MQTT:

To start MQTT using docker compose, the Docker image can be downloaded, created and started using a simple docker-compose.yml file. The file can be filled with any text editor as follows and then customized:

Filename: docker-compose.yml, Content:

version: "2"
    image: eclipse-mosquitto
    container_name: mqtt
    restart: always
      - ./mosquitto/data:/mosquitto/data
      - ./mosquitto/log:/mosquitto/log
      - "1883:1883"
      - "9001:9001"

The example uses Docker volumes and not bind mounts to permanently store data.

📢 A new post will probably be linked here on 2022-10-13: Docker Volumes vs Bind Mounts allow push notifications?

docker-compose up starts the container:

docker-compose up

Attention the folder /mosquitto/config and therefore the config file: mosquitto.conf is still missing in the docker-compose file for now.This is initially created at startup and is only located inside the container, so all settings would be lost when the container is restarted. At this point, the container already works with the default settings, but allows all devices to communicate with the broker without a password:

c:\temp\mosquitto>docker-compose up
Recreating mqtt ... done
Attaching to mqtt
mqtt         | 1642331896: mosquitto version 2.0.14 starting
mqtt         | 1642331896: Config loaded from /mosquitto/config/mosquitto.conf.
mqtt         | 1642331896: Starting in local only mode. Connections will only be possible from clients running on this machine.
mqtt         | 1642331896: Create a configuration file which defines a listener to allow remote access.
mqtt         | 1642331896: For more details see
mqtt         | 1642331896: Opening ipv4 listen socket on port 1883.
mqtt         | 1642331896: Opening ipv6 listen socket on port 1883.
mqtt         | 1642331896: Error: Address not available
mqtt         | 1642331896: mosquitto version 2.0.14 running

So that we can assign a password for MQTT and the settings remain after restarting the container, I connected into the container and created a password file in it:

c:\temp\mosquitto> docker exec -it mqtt sh
/ # mosquitto_passwd -b -c passwd mqtt myMQTTPassword
/ # cat passwd

The contents of the output mqtt:??? can then be put into the passwd file in the /config folder:

Then another new file with the configuration: mosquitto.conf with the following content:

port 1883
listener 9001
protocol websockets
persistence true
persistence_location /mosquitto/data
allow_anonymous false
password_file /mosquitto/config/passwd

Afterwards, the Docker container can be stopped, the /mosquitto/config folder can be added and started again:

Adjustments to the docker-compose.yml file: Addition of /config:

version: "2"
    image: eclipse-mosquitto
    container_name: mqtt
    restart: always
      - ./mosquitto/config:/mosquitto/config
      - ./mosquitto/data:/mosquitto/data
      - ./mosquitto/log:/mosquitto/log
      - "1883:1883"
      - "9001:9001"

Restarting the container uses the created configuration and the assigned password:

docker-compose up -d

A look into the output of the container (docker logs) shows us the successful start:

c:\temp\mosquitto>docker logs mqtt -f
1642333000: mosquitto version 2.0.14 starting
1642333000: Config loaded from /mosquitto/config/mosquitto.conf.
1642333000: Opening websockets listen socket on port 9001.
1642333000: Opening ipv4 listen socket on port 1883.
1642333000: Opening ipv6 listen socket on port 1883.
1642333000: mosquitto version 2.0.14 running

see, Home Assistant Docker Conbee 2 and Zigbee2MQTT / deCONZ

Display of connections: Logs

In the Docker logs, the connection of individual devices can be observed:

docker logs mqtt -f
1641494340: New connection from on port 1883.
1641494340: New client connected from as xxxxxx (p2, c1, k60, u'mqtt').
1641494608: Client xxx closed its connection.
1641496053: Saving in-memory database to /mosquitto/data/mosquitto.db.
positive Bewertung({{pro_count}})
Rate Post:
{{percentage}} % positive
negative Bewertung({{con_count}})

THANK YOU for your review!

Updated: 2022-09-20 von Bernhard

Top articles in this section

Home Assistant Docker Conbee 2 and Zigbee2MQTT / deCONZ
Thanks to numerous integration options,Home Assistant is a simple platform for controlling a wide range of smart home devices. Compared to ioBroker, I found it much easier to get started with Home Assistant. While for ioBroker I was still searching for which frontend I could use for my dashboards, with Home-Assistant I had a ready-made system out of the box. Home Assistant's Lovelance dashboards can be easily clicked together in the GUI and adapted for special customizations in the code editor...

Running Docker Mailserver yourself | a field report
With the help of a suitable Docker image, it is relatively easy to run a mail server yourself. I originally used the integrated mail server of the Host Europe vServer (Plesk) and came across a very simple Docker container while looking for a replacement. The lightweight container provides a mail server without a graphical management interface, but can be managed with a few simple commands. Any email client can be used to send and receive the mails, for this POP3 or IMAP is offered for receiving...

Nextcloud Server Docker | Setup + https: Let's Encrypt [ssl]
To synchronize contacts, appointments, and photos of my NAS, I tested Nextcloud and thus turned my back on other cloud providers for my private data. Thanks to Docker, the installation is easier and more flexible than ever, allowing Nextcloud to run on almost any hardware.

Questions / Comments

By continuing to browse the site, you agree to our use of cookies. More Details