ntim/dnsmasq repository overview

⁠docker-dnsmasq

This is a dnsmasq⁠ Docker image forked from andyshinn⁠. It is only 5 MB in size and provides an entrypoint to the dnsmasq binary. Which is suitable for running as a service in Docker swarm mode.

⁠Usage

The latest image uses dnsmasq 2.78 based on Alpine 3.7.

⁠Entrypoint

The entrypoint is

 dnsmasq -k --log-facility - -u root

The option -k keeps dnsmasq running in the foreground enabling docker health checks. The second option --log-facility - routes logging to stdout. To avoid having to set linux capabilities, dnsmasq is told to run as root instead of nobody by setting the parameter -u root.

⁠Deploy as a service

docker service create --name dnsmasq \
	--publish 53:53/tcp --publish 53:53/udp \
	ntim/dnsmasq:latest

⁠Configuration

Per default, dnsmasq looks for configuration files in the /etc/dnsmasq.d/ directory. The following configuration file overwrites DNS requests to example.com and its subdomains (useful for SNI routing) to the ip 192.168.99.99

cat <<EOF > dnsmasq_example.conf
address=/example.com/192.168.99.99
EOF

Add docker configuration

docker config create dnsmasq_example.conf example.conf

and deploy the service with

docker service create --name dnsmasq \
	--publish 53:53/tcp --publish 53:53/udp \
	--config source=dnsmasq_example.conf,target=/etc/dnsmasq.d/example.conf \
	ntim/dnsmasq:latest

mounting the configuration.