Failing consul health check on local machine

I have Consul running via docker using docker-compose

version: '3'

services:  
  consul:
    image: unifio/consul:latest
    ports:
      - "8500:8500"
      - "8300:8300"
    volumes: 
      - ./config:/config
      - ./.data/consul:/data
    command: agent -server -data-dir=/data -ui -bind 0.0.0.0 -client 0.0.0.0 -bootstrap-expect=1
  mongo:
    image: mongo
    ports:
      - "27017:27017"
      - "27018:27018"
    volumes:
      - ./.data/mongodb:/data/db
    command: mongod --bind_ip_all

and have a nodejs service running on port 6001 which exposes a /health endpoint for health checks. I am able to register the service via this consul package. However, visiting the consul UI I can see that the service has a status of failing because the health check is not working.

The UI show this message:

Get http://127.0.0.1:6001/health: dial tcp 127.0.0.1:6001: getsockopt: connection refused

Not sure why is not working exactly, but I kind of sense that i may have misconfigured consul. Any help would be great.

Solution

Consul is running in your docker container. When you use 127.0.0.1 in this container, it refers to itself, not to your host.

You need to use a host IP that is known to your container (and of course make sure your service is reachable and listening on this particular IP).

In most cases, you should be able to contact your host from a container through the default docker0 bridge ip that you can get with ip addr show dev docker0 from your host as outlined in this other answer.

The best solution IMO is to discover the gateway that your container is using which will point to the particular bridge IP on your host (i.e. the bridge created for your docker-compose project when starting it). There are several methods you can use to discover this ip from the container depending on the installed tooling and your linux flavor.