how does docker-compose map my service names into IP addresses?

Question

I have a docker-compose.yml file that I use to run a web application.

version: \'3\'
services:
  web:
    entrypoint: gunicorn myapp.wsgi:application --bind 0.0         


        

Answer 1

Docker provides a DNS service (search for “automatic DNS resolution between containers”), and Docker Compose provides a default “user-defined” network that uses it. If you look at /etc/resolv.conf inside your container, it should point at a Docker-private IP addresses which provides hostname resolution for both the general Internet and for other containers.

More specifically in a Docker Compose context, the name of each entry in the services: block is resolvable as a host name by other containers launched from the same docker-compose.yml file. You do not need to set container_name:, hostname:, links:, or networks:; this is all configured automatically for you.