Mosquitto mqtt broker is not suitable for large-scale applications, while EMQX is designed for high concurrency and massive connections, and supports clustering. Let’s see how to install and use EMQX on a Linux server.
Installation
1. download and install EMQX
my server is x86_64 architecture and ubuntu 20.04, so I choose the corresponding version on this page: https://www.emqx.com/en/downloads-and-install/enterprise?os=Ubuntu
and install it following the instructions
2. start EMQX
sudo systemctl start emqx
sudo systemctl enable emqx
sudo systemctl status emqx
sudo emqx ctl status
3. test EMQX
install mqtt client
sudo apt install -y mosquitto-clients
subscribe a topic in a terminal
mosquitto_sub -h 127.0.0.1 -t test/topic
publish a message in another terminal
mosquitto_pub -h 127.0.0.1 -t test/topic -m "hello emqx"
4. config EMQX
the default configuration file is located at /etc/emqx/emqx.conf, you can edit it according to your needs.
in a production environment, you should config EMQX to secure it, for example, set username and password for clients to connect EMQX.
with EMQX 5.10.1, you can set username and password on the dashboard, the default address is http://127.0.0.1:18083.
and the default username is admin, password is public. you can change the password after login.
then on the Dashboard -> Access Control -> Authentication, click Create and select Password-Based and Built-in Database, and save.
then click and enter into the Built-in Database, and Add a user on the User Management tab.
5. test with username and password
subscribe a topic in a terminal
mosquitto_sub -h 127.0.0.1 -t test/topic -u your_username -P your_password
publish a message in another terminal
mosquitto_pub -h 127.0.0.1 -t test/topic -m "hello emqx" -u your_username -P your_password
clients
use python paho-mqtt client to publish in a topic
and use react mqtt client to subscribe the topic and display the message
EMQX default supports websocket, you can use this command to check it:
$ emqx ctl listeners
tcp:default
listen_on : 0.0.0.0:1883
acceptors : 16
proxy_protocol : false
enbale : true
running : true
current_conn : 0
max_conns : 1048576
shutdown_count : [{bad_username_or_password,4},{tcp_closed,1}]
ssl:default
listen_on : 0.0.0.0:8883
acceptors : 16
proxy_protocol : false
enbale : true
running : true
current_conn : 0
max_conns : 1048576
shutdown_count : [{bad_username_or_password,1},{malformed_packet,1}]
ws:default
listen_on : 0.0.0.0:8083
acceptors : 16
proxy_protocol : false
enbale : true
running : true
current_conn : 1
max_conns : infinity
shutdown_count : []
wss:default
listen_on : 0.0.0.0:8084
acceptors : 16
proxy_protocol : false
enbale : true
running : true
current_conn : 0
max_conns : infinity
shutdown_count : []
brower can’t use tcp protocol, so we need to use websocket protocol to connect EMQX.
so the python paho-mqtt client should be like this:
import paho.mqtt.client as mqtt
mqttc = mqtt.Client(
mqtt.CallbackAPIVersion.VERSION2, transport="websockets"
)
mqttc.username_pw_set(username, password)
# port should be 8083 for websocket
mqttc.connect(host, 8083)
mqttc.loop_start()
and the react mqtt client should be like this:
import mqtt from "mqtt";
// port should be 8083 for websocket
const client = mqtt.connect("ws://localhost:8083", {
username: process.env.REACT_APP_MQTT_USERNAME,
password: process.env.REACT_APP_MQTT_PASSWORD,
clientId: `web_${Math.random().toString(16).slice(3)}`,
keepalive: 60,
clean: true,
reconnectPeriod: 1000,
});
wss (websocket secure) is also supported by EMQX, but you need to config SSL certificate for it.