Simplified Docker container hostname resolution

docker-dnshosts (a fork of docker-hosts with a still terrible name) maintains a file in the format of /etc/hosts that contains IP addresses and hostnames of Docker containers. Contrary to the original solution in docker-hosts, mounting a file is not the way to go with docker-dnshosts (although the same file is generated). The idea behind docker-dnshosts is to feed dnsmasq with the hosts information. This way hostname resolution works as expected (if the containers are provided with a dnsmasq dns server) without loosing the features given by docker to the /etc/hosts file.

The solution was inspired by Amartynov's dnsmasq and docker solution, yet I didn't like the fact to always manually call a script after changing containers. This solution builds on the same principle but reacts to docker events and HUPs dnsmasq automatically after finding a change.

building

This project uses godep. Godep must be available on your path.

make

running

Start the docker-dnshosts process and give it the path to the container hosts file, which is bound to dnsmasq:

docker-host /path/to/hosts

Optionally specify DOCKER_HOST environment variable.

Then start a container:

docker run -i -t --dns=your.dns.server centos /bin/bash

Within the centos container, you can just ping any other container running on the same docker host.

running in Docker

Create an empty file at /var/lib/docker/hosts, make it mode 0644 and owned by nobody:nobody.

docker run \
    -d \
    -v /var/run/docker.sock:/var/run/docker.sock \
    -v /path/to/hosts:/srv/hosts \
    blalor/docker-dnshosts --domain-name=dev.docker /srv/hosts