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?
3 Answers
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 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 
