Turned a Raspberry Pi Zero into an MQTT Broker

Introduction

#

Recently, I was thinking about setting up an MQTT Broker. Since the Raspberry Pi I currently have on hand is being used as a NAS, I decided to build the MQTT Broker using a Raspberry Pi Zero W that I bought last year.

I originally bought this Raspberry Pi Zero from Akizuki Denshi last year just to meet the free shipping requirement, so I’ve finally found a use for it…

Setup

#

The desktop PC I use for development doesn’t have an SD card slot, so I usually use an SD-to-USB adapter, but I’ve misplaced it again. However, since the laptop I recently bought has an SD card slot, I used that to write the OS to the SD card.

The Raspberry Pi Zero is certainly cheap (compared to a regular Raspberry Pi), but the trade-off is low performance. With only 512 MB of memory and a single-core 1GHz CPU, the specs are quite low. Because of this, I installed Raspberry Pi OS Lite, which doesn’t have a desktop environment.

Connecting HDMI and LAN cables is a hassle in the first place, so I think remote control via SSH is definitely the best approach.

By the way, the MQTT software I used this time is Mosquitto.

My bachelor’s thesis involved research using MQTT, so this shouldn’t have been too difficult for me. But since quite a bit of time has passed since then, I had forgotten some of the finer details (lol). Well, thanks to ChatGPT, I was able to get it working properly in the end.

Notes

#

Here are the commands I used frequently this time.

• ps aux Displays a list of running tasks.
• ufw status Checks the firewall status.
• ufw allow 1883/tcp Allows TCP port 1883.
• ip addr show Displays the IP addresses of network interfaces.
• sudo netstat -tulnp Displays current network connections and listening ports.
• sudo netstat -tulnp | grep 1883 Searches for the process using port 1883.
• kill < PID > Terminates the process with the specified PID.