This is POC that demonstrates Prometheus service discovery in Docker Swarm. It is implemented as a standalone tool that writes the scrape targets to a file, that is then read by Prometheus. This uses the <file_sd_config> config directive available in Prometheus.

The discovery tool expects to have access to the Swarm API using /var/run/docker.sock. The provided docker-compose.yaml is configured to mount the docker.sock file inside the container, and this requires that the swarm-discover container is placed on the Swarm manager node.

The only thing required to run Prometheus and the discovery tool is to launch a Swarm stack using the provided docker-compose.yaml file.

$ docker stack deploy -c docker-compose.yaml prometheus