docker-dns

Simple dns server to serve Docker container IP addresses. Had too much coffe and could not sleep. Useful for me, maybe even for you.

Setup

Generate config:

./docker-dns --createConfig

If you feel like, you can edit config

Add this line to your local dnsmasq resolver

server=/yourtld/127.0.0.1#8053

Then run it

./docker-dns --config=/path/to/conf.json

Check if it works:

dig @127.0.0.1 containerName.tld A

Usage

./bin/docker-dns -h
  -config="": Path to config file
  -createConfig=false: Print default config file to stdout
  -docker="unix:///var/run/docker.sock": Address for docker client (HTTP or Unix)
  -listen="127.0.0.1:8053": Listen address
  -loglevel="info": Logrus loglevel
  -tld="docker.": TLD to serve
  -ttl=60: Default TT

systemd service

cp server /usr/local/bin/docker-dns
sudo cp docker-dns.service /etc/systemd/system/docker-dns.service
sudo systemctl daemon-reload
sudo systemctl enable docker-dns
sudo systemctl start docker-dns.service
sudo systemctl status docker-dns.service

Use it with NetworkManager

Make sure dns=dnsmasq in /etc/NetworkManager/dnsmasq.d/docker-dns

[main]
plugins=ifupdown,keyfile,dnsmasq
dns=dnsmasq

[ifupdown]
managed=false

Create file /etc/NetworkManager/dnsmasq.d/docker-dns

server=/docker/127.0.0.1#8053

sudo service network-manager restart