Create 1000 mqtt clients (in 1000 threads) to test broker connections.

multi.py

#!/usr/bin/python

import mosquitto
import time

def on_connect(mosq, obj, rc):
    print("Connected: "+mosq._client_id)

def on_disconnect(mosq, obj, rc):
    print("Disconnected: "+mosq._client_id + " ("+str(rc)+")")

for i in range(0, 1000):
    mosq = mosquitto.Mosquitto()
    mosq.on_connect = on_connect
    mosq.on_disconnect = on_disconnect
    mosq.connect("localhost", 1883, 60)
    mosq.subscribe("$SYS/#", 0)
    mosq.loop_start()

while True:
    time.sleep(1)

multi2.py

#!/usr/bin/python

import time
import subprocess

for i in range(0, 1000):
    client = subprocess.Popen(('mosquitto_sub', '-t', '$SYS/#', '-p', '1883', '-h', 'localhost'))

while True:
    time.sleep(1)