Using --add-host or extra_hosts with docker-compose

Question

I am using docker-compose to run a test environment, that consists of about 5 different containers. The inter-container links and the shared volumes (volumes-from)

Answer 1

Basic docker-compose.yml with extra hosts:

version: '3'
services:
api:
    build: .
    ports:
        - "5003:5003"
    extra_hosts:
        - "your-host.name.com:162.242.195.82" #host and ip
        - "your-host--1.name.com your-host--2.name.com:50.31.209.229" #multiple hostnames with same ip
        

The content in the /etc/hosts file in the created container:

162.242.195.82  your-host.name.com
50.31.209.229   your-host--1.name.com your-host--2.name.com

You can check the /etc/hosts file with the following commands:

$ docker-compose -f path/to/file/docker-compose.yml run api bash  # 'api' is service name
#then inside container bash
root@f7c436910676:/app# cat /etc/hosts