MQTT Installation

Install mosquitto broker and mosquitto-clients client packages.

  sudo apt -y update
  sudo apt -y install mosquitto
  sudo apt -y install mosquitto-clients

Configuration

Configure the broker. The mosquitto broker’s configuration file is located at /etc/mosquitto/mosquitto.conf. Open and edit this file. To configure MQTT broker to be authenticated.
```
  sudo vi /etc/mosquitto/mosquitto.conf
```
Delete this line.
```
  include_dir /etc/mosquitto/conf.d
```
Add the following lines to the bottom of the file.
```
  allow_anonymous false
  password_file /etc/mosquitto/pwfile
  listener 1883
```
- anyone connecting to our broker need to provide username and password
- mosquitto to listen for messages on port number 1883
- If you don’t want the broker to require a username and password, don’t include the first two lines that we added.
tell mosquitto what the username and password are. Replace <username> with the username that you would like. Then enter the password you would like when prompted. When editing the configuration file, you specified a different password_file path, replace the path below with the one you used
```
 sudo mosquitto_passwd -c /etc/mosquitto/pwfile <username>
```
Reboot RPi
```
  sudo reboot
```
Start the broker
```
  sudo service mosquitto start
```