docker-compose : Why agent & app service fail due to hostname?

Question

Below is the working docker-compose file in v2 spec:

version: \'2\'

volumes:
  webroot:
    driver: local


services:
  app: # Launch uwsgi application server
          


        

Answer 1

that is how Docker works because the hostname is not unique and that will lead to a problem if you give two containers the same hostname therefore compose will always use the service name for DNS resolution