Official Eclipse Mosquitto 2.x MQTT broker (continuously updated) with a minimal Unraid template: host networking and a single /config folder. Supports MQTT protocol 5 (required by modern Home Assistant).

HOW TO MANAGE USERS (no coding knowledge needed — just copy, replace, paste):

1. Open the Unraid main menu and click TERMINAL.
2. Copy the command below and paste it into the terminal (press Ctrl+Shift+V or right-click in most browsers).
   Replace YOURNAME and YOURPASSWORD with your own values.
   If your container has a different name than "Mosquitto", replace it there too.

ADD A NEW USER:
docker exec Mosquitto sh -c "mosquitto_passwd -b /config/passwords.mqtt YOURNAME 'YOURPASSWORD'"
(If the terminal says the file does not exist, use this version instead:
docker exec Mosquitto sh -c "mosquitto_passwd -c -b /config/passwords.mqtt YOURNAME 'YOURPASSWORD'")

CHANGE A USER'S PASSWORD:
Run the ADD command again with the same name and the new password.

REMOVE A USER:
sed -i '/^YOURNAME:/d' /mnt/user/appdata/Mosquitto/passwords.mqtt

SEE ALL USERS:
cut -d: -f1 /mnt/user/appdata/Mosquitto/passwords.mqtt

1. After ANY change above, restart the container so it takes effect:
   docker restart Mosquitto
   (Or simply press the Restart button in the Docker tab of the Unraid web UI.)

WARNING: never run the ADD command with the -c flag when users already exist — it deletes all other users. Use -c only the very first time, when no password file exists yet.
After a restart, clients (e.g. Home Assistant) reconnect automatically; if one does not, restart that app.