Docker composer recipe for Node-RED + Mosquitto + microservices discovery with Consul

Want to play with the latest Node-RED additions in a safe place without installing and configuring a real host? Docker and composer are the right tools.

What's Docker

Docker needs not so many words (or perhaps too many if you never used it).

Docker is a framework for working with containers on a host. It makes it possible to describe an environment (virtual host), build its image and bring that image up as a container without ever modifying the configuration and structure of the hosting machine.

Of course, building and starting many different containers for giving life to many different services is the main usage for Docker.

Please see here for more details.

Installing docker-compose is out of the scope of this example, just as a (possibly very soon broken) reference I'm currently using this couple of commands to get the latest docker-composer (as root):

$ curl -L https://github.com/docker/compose/releases/download/1.8.1/docker-compose-`uname -s`-`uname -m` > /usr/local/bin/docker-compose
$ chmod +x /usr/local/bin/docker-compose

What's docker-compose

docker-compose is a tool you will never stop using after having discovered it. It's a set of Python based scripts that can easily manage building / pulling / bringing up and down Docker based services (images and running containers) based on a very simple and self documenting YAML configuration file.

Please see here for more details.

Installing docker-compose is out of the scope of this example, just as a (possibly very soon broken) reference I'm currently using this couple of commands to get the latest docker-composer (as root):

$ curl -L https://github.com/docker/compose/releases/download/1.8.1/docker-compose-`uname -s`-`uname -m` > /usr/local/bin/docker-compose
$ chmod +x /usr/local/bin/docker-compose

What's Consul (and Registrator)

Consul with Registrator is among the most complete and simple to be used services for microservices discovery and health control.

Consul is a server sitting in the same (virtual) network where your services will come up and down; Registrator is another server speaking to your Docker daemon and informing Consul about Docker managed services.

Please see here for more details.

What are we doing here

With this example I'm putting this together:

• Docker containers for a Node-RED and a Mosquitto servers will be created and started, with a well described configuration;
• Docker containers for Consul and Registrator servers will be pulled from available images on the Internet and started;
• Node-RED will be then available at its usual port 1880 of the hosting machine (your portable perhaps) for creating your next flow, and playing with its features;
• while playing with Node-RED you will be able to use the local MQTT brocker sitting in the same host offered by the related Mosquitto container;
• Consul and Registrator will inform in a handy web page reached at the usual port 8500 of the hosting machine about Node-RED and Mosquitto services being up and running

Where to start

You just need to:

• install Docker and docker-compose
• clone this repo and log into its folder
• build and pull the containers: docker-compose build && docker-compose pull
• start the services: docker-compose up -d and enjoy using Node-RED by browsing at localhost:1880, while logging running services at localhost:8500
• stop the services: docker-compose stop

In order to be able to check messages created while starting the services please use docker-compose up instead of docker-compose up -d, and hit CTRL+C for stopping.

Your Node-RED flow (the flows.json file) and related settings will stay saved inside nodered/runtime for your reference and backup purposes.

Scaling

docker-compose has the ability to scale services very easily, with one single command you can start more instances of the same service (replicating docker containers). This is still possible in this recipe but some modifications must be made, notably to the way the containers now use and save configuration files on mounted folders from the host. Without doing this you will end up with conflicts between the instances, and this is (for now) out of the scope of this example.

More Node-RED libraries

In case you need to install and use available libraries for Node-RED you just need to modify the Dockerfile contained inside the nodered folder and build again the container.

Credits

• http://nodered.org/
• https://github.com/jllopis/docker-mosquitto
• https://gist.github.com/dceejay/9435867