Mosquitto MQTT broker installation on Raspberry pi

Update your system first. Type the following command into the terminal or SSH console.

sudo apt-get update

sudo apt-get upgrade

The Mosquitto MQTT broker can be easily installed from Debian package sources. 

sudo apt-get install mosquitto

Install the Mosquitto client as well.

sudo apt-get install mosquitto-clients

At the end of the installation, the service is enabled.

sudo systemctl enable mosquitto

Once we have that, we can use the MQTT broker. The Mosquitto server starts automatically after installation.

The Mosquitto server registers itself as a system service and starts automatically at system startup. 

Use the following commands to start, stop, or restart the Mosquitto MQTT Broker service.

sudo systemctl start mosquitto

sudo systemctl stop mosquitto

sudo systemctl restart mosquitto

You can disable or enable autorun.

sudo systemctl disable mosquitto

sudo systemctl enable mosquitto

Let’s see if our server is working. Open two Terminals or SSH windows. On the first Terminal, subscribe to the “/test/topic” topic. Here you can receive messages.

mosquitto_sub -h localhost -t /test/topic

At the second terminal, we can send a message to the Mosquitto MQTT broker. Enter the following command and if everything is OK, this message should appear in the first terminal window.

mosquitto_pub -h localhost -t /test/topic -m "Hello Mosquitto!"

If we wish, we can password protect our Mqtt Broker. Mosquitto includes a service called mosquitto_passwd to create a password file. Copy the following command and run it on the terminal. Enter the password.

sudo mosquitto_passwd -c /etc/mosquitto/pwd myusername

The username “myusername” and the corresponding password are created in the password file “/etc/mosquitto/pwd”.

Then create the configuration file for Mosquitto.

sudo nano /etc/mosquitto/conf.d/default.conf

Add these two lines and save.

allow_anonymous false
password_file /etc/mosquitto/pwd

 Restart the Mosquitto

systemctl restart mosquitto

Let’s test it.

pi@raspberrypi:~ $ mosquitto_pub -h localhost -t /test/topic -m "Hello Mosquitto!"
Connection Refused: not authorised.

It doesn’t work without a password, we get an error message. Complete the command with the username and password pair as follows.

mosquitto_sub -h localhost -t /test/button -u myusername -P mypassword

mosquitto_pub -h localhost -t /test/topic -m "Hello Mosquitto!"  -u myusername -P mypassword

We now have a small MQTT server that can run energy efficiently e.g. on a Raspberry Pi.

With this simple little MQTT client app we can connect our Android phone to the MQTT server

Good luck for that.