First, I wanted to use highly concurrent and highly safe system so I found RUST(https://en.wikipedia.org/wiki/Rust_(programming_language) to handle docker swarm deployment. Later, I plan to turn each swarn node into a automated task engine (spun up on fly by master or destroyed), and link it to Swarm, which will handle the AI of the clustered network.

Make sure Docker is fully installed - my installation had docker supplementry files but I had to run brew cask install docker to fix it.

To create a Swarm cluster: Use the shell script (setup-swarm.sh) to setup a cluster with 3 nodes (1 Manager & 2 Workers)

Issue the following command to execute the script:

chmod +x setup-swarm.sh
./setup-swarm.sh

At this moment, we have 3 nodes.

• We use an overlay network named traefik-net, on which we add the services we want to expose to Traefik.
• We use constraints to deploy the APIs on workers & Traefik on Swarm manager.
• Traefik container is configured to listen on port 80 for the standard HTTP traffic, but also exposes port 8080 for a web dashboard.
• The use of docker socket /var/run/docker.sock This allows Traefik to listen to Docker Daemon events, and reconfigure itself when containers are started/stopped.
• The label traefik.frontend.rule is used by Træfik to determine which container to use for which Request Path.
• The configs part create a configuration file for Traefik from config.toml(it enables the Docker backend)

Run docker swarm init or docker swarm join to initialise the swarm

In order to deploy our stack, we should execute the following command:

docker stack deploy --compose-file docker-compose.yml api

However, we may encounter this error:

Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?

Make sure that docker is running!

To check the overlay network:

docker network ls

Traefik configuration:

docker config ls

To display the configuration content:

docker config inspect api_traefik-config — pretty

And finally, to list all the services:

docker stack ps api

A lot of this code used https://github.com/mlabouardy/alb-go as a basis, and followed the corresponding tutorial https://hackernoon.com/architecting-a-highly-scalable-golang-api-with-docker-swarm-traefik-875d1871cc1f. https://www.upcloud.com/support/how-to-configure-docker-swarm/ was quite informative too, so I've used a lot of that advice too. Things went wrong, so https://forums.docker.com/t/cannot-connect-to-the-docker-daemon-is-the-docker-daemon-running-on-this-host/8925 helped a bit too. For event listening, http://blog.scoutapp.com/articles/2015/06/05/monitoring-docker-events. Also for raspberry pi images https://hub.docker.com/r/resin/rpi-raspbian/