CODEWITHSUNDEEP
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Pieter
Pieter

Reputation: 2553

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

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) works wonderfully. I also expose some ports up to the host machine, which works nicely.

What I am missing is a way to link some of my real servers into this environment, without hardcoding ip address. With docker run, you could use --add-host to add another line in your /etc/hosts file. Is there any way to do something similar with docker-compose?

Upvotes: 213

Views: 470703

Answers (3)

Shubham
Shubham

Reputation: 2210

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

Upvotes: 127

jpetazzo
jpetazzo

Reputation: 15511

This works still docker-compose 1.3 with extra_hosts parameter:

rng:
  build: rng
  extra_hosts:
    seed: 1.2.3.4
    tree: 4.3.2.1

Upvotes: 148

oneklc
oneklc

Reputation: 3184

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

Upvotes: 192

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