How to Deploy MQTT with Mosquitto and Monitor It Using Zabbix Agent2

MQTT Protocol Overview

MQTT (Message Queuing Telemetry Transport) is an ISO‑standard publish/subscribe protocol designed for low‑power devices and unreliable networks. It is widely used in automotive, manufacturing, telecom, oil & gas, satellite‑linked sensors, medical devices, home automation, and mobile apps due to its small footprint and low power consumption.

Components

MQTT broker – the central hub that routes messages between clients.

MQTT client – any device that connects to the broker; publishers send messages, subscribers receive them by subscribing to topics.

Deploying an MQTT Broker (Mosquitto) on CentOS

Install and build Mosquitto from source:

<code>mkdir data && cd data
wget http://mosquitto.org/files/source/mosquitto-1.6.8.tar.gz
tar -zxvf mosquitto-1.6.8.tar.gz
cd mosquitto-1.6.8
make && make install
ln -s /usr/local/lib/libmosquitto.so.1 /usr/lib/libmosquitto.so.1
ldconfig</code>

Edit

mosquitto.conf

to set the listening address and authentication, then start the broker:

<code>mosquitto -v</code>

Testing the Broker

<code>mosquitto_sub -v -t sensor</code>

<code>mosquitto_pub -t sensor -m 12</code>

Subscribers will receive the published messages.

Collecting MQTT Messages with Zabbix Agent2

Zabbix Agent2 acts as an MQTT subscriber. The agent is written in Go, allowing custom plugins. The MQTT plugin implements a watcher that pushes new data to the Zabbix server.

1. Build Zabbix Agent2 with the MQTT Plugin

<code>yum install golang
git clone https://git.zabbix.com/scm/zbx/zabbix.git --depth 1 zabbix-agent2
cd zabbix-agent2
git submodule add https://github.com/v-zhuravlev/zbx_plugin_mqtt.git src/go/plugins/mqtt</code>

2. Import the Plugin

<code>vi src/go/plugins/plugins.go</code>

<code>package plugins
import (
    _ "zabbix.com/plugins/log"
    _ "zabbix.com/plugins/systemrun"
    _ "zabbix.com/plugins/zabbix/async"
    _ "zabbix.com/plugins/zabbix/stats"
    _ "zabbix.com/plugins/zabbix/sync"
    _ "zabbix.com/plugins/mqtt"
)</code>

3. Compile and Install Agent2

<code>./bootstrap.sh
pushd .
cd src/go/
go mod vendor
popd
./configure --enable-agent2 --enable-static
make install</code>

4. Configure the Plugin

Add entries to

zabbix_agent2.conf

such as:

<code>Plugins.MQTTSubscribe.Username = <mqtt_user>
Plugins.MQTTSubscribe.Password = <mqtt_password>
Plugins.MQTTSubscribe.ClientID = zabbix-agent2-mqtt-client
Plugins.MQTTSubscribe.Timeout = 5</code>

5. Start the Agent

<code>cd /root/zabbix_agent/src/go/bin
./zabbix_agent2 -c ../conf/zabbix_agent2.conf</code>

The plugin pushes received MQTT data to the Zabbix server.

6. Create a Zabbix Item

Use a key of the form:

<code>mqtt.subscribe[<MQTT broker URL>,<MQTT topic>]</code>

Set the item type to “active”. The data appears in the Zabbix frontend in real time.