Consul & Registrator & Rails Service all together in separate Docker container

1.Start a container running Consul:

Here we use this image: https://hub.docker.com/r/progrium/consul/

$ docker run -it -h node -p 8500:8500 -p 53:53/udp progrium/consul -server -bootstrap -advertise  $DOCKER_IP

How to check that Consul is running:

Method1:

In Docker-Machine, run

$ docker ps

Will see running Consul container:

We can also check the logs:

$ docker logs $CONTAINER_ID

Method2:

Browse to $DOCKER_IP:8500 there is a dashboard to see the services that are registered in Consul:

2.Start a container running Registrator

Here we use this image: https://hub.docker.com/r/gliderlabs/registrator/

Registrator automatically registers and deregisters services for any Docker container by inspecting containers as they come online.

Registrator watches for new Docker containers and inspects them to determine what services they provide. For our purposes, a service is anything listening on a port. Any services Registrator finds on a container, they will be added to a service registry, such as Consul or etcd.

$ docker run -it -v /var/run/docker.sock:/tmp/docker.sock -h $DOCKER_IP gliderlabs/registrator consul://$DOCKER_IP:8500

How to check that Registrator is running?

In Docker-Machine, run

$ docker ps

Will see running Registrator container:

We can also check the logs:

$ docker logs $CONTAINER_ID

3. Start a web service and let Registrator automatically register it on Consul

In command line, into a directory that has proper rails app, Dockerfile and docker-compose.yml file in place.

$ docker-compose build
$ docker-compose run web bundle exec rake sample_data:populate
$ docker-compose run -p 3000 -e 'SERVICE_NAME=romui-web' web rails s

How to check that this service is registered?

Method1:

Use Consul API:

$ curl $DOCKER_IP/v1/catalog/services

We can check the service details using Consul HTTP API:

$ curl http://localhost:8500/v1/catalog/service/$SERVICE_NAME

Method2:

Check in Consul UI:

4. Find the IP address and port of the service from Consul UI, and start using the service.

Now we are ready to access the service from browser: