denniscgc / mqtt-testbed

Distributed MQTT testbed based on docker compose

This repo contains a docker compose and then specific container configurations.

Docker Compose Concept

Pre-requisites

The docker compose configuration has the following pre-requisites:

• a docker network has to be created before hand with the following command

$ docker network create --gateway 10.5.0.254 --subnet 10.5.0.0/16 mqtt-net

• an mqtt-stresser docker container needs to be created from the mqtt-stresser submodule with the following command

$ make container

• empty logs have to be created, due to the way Docker volume mounts work

$ ./setup-logs.sh

Services

Once the pre-requisites are met, the services can be started with

docker-compose up

Docker will create the following services

• MQTT Broker 1
• MQTT Broker 2
• MQTT Broker 3
• MQTT stresser 1
• MQTT stresser 2
• MQTT stresser 3
• MQTT collectd 1
• MQTT collectd 2
• MQTT collectd 3
• cloud bridge

Brokers

Brokers 1 to 3 have specific detailed configuration to startup and configure channel bridges to the cloud-bridge. Each subfolder contains a dedicated configuration for each broker, where logging and bridging can be modified.

Stressers

Stressers are containers running https://github.com/inovex/mqtt-stresser/ which need to be pre-built and available to the docker engine. This is already considered by the creators of the stresser, so all it takes is

cd mqtt-stresser
make container

The stress configurations are inside the docker-compose configuration, they are not persistent and so their configuration exists purely as a command line set of parameters within the container definition in docker. For other options see https://stackoverflow.com/questions/51999953/load-testing-services-for-mqtt

collectd

Collectd is not available as a package pre-built with mqtt support, so included in the repo there is a copy of the collectd source repo and a Dockerfile used to build a custom collectd image used by the compose environment. In order to correctly build the image, the only thing needed is to assign it the proper tag

cd collectd-docker
docker build . -t collectd:custom-mqtt

Visualizing MQTT data

There are many ways to visualize what goes on MQTT channels and brokers. One is mosquitto clients, like pub/sub from the command line. More advanced are UI tools like https://mqtt-explorer.com/ and https://mqttx.app/ which can connect to mulitple brokers at the same time and visualize topic updates.