Using --add-host or extra_hosts with docker-compose
https://github.com/compose-spec/compose-spec/blob/master/spec.md#extra_hosts
extra_hosts - Add hostname mappings. Uses the same values as the docker client --add-host parameter.
extra_hosts:
- "somehost:162.242.195.82"
- "otherhost:50.31.209.229"
An entry with the ip address and hostname will be created in /etc/hosts > inside containers for this service, e.g:
162.242.195.82 somehost
50.31.209.229 otherhost
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
I have great news: this will be in Compose 1.3!
I'm using it in the current RC (RC1) like this:
rng:
build: rng
extra_hosts:
seed: 1.2.3.4
tree: 4.3.2.1