Consul, DNS and Dnsmasq

While at Craft I decided to have a quick look at Consul, a new service discovery framework with a few intersting features. One of the main selling points is a DNS interface with a nice API. The Introduction shows how to use this via the dig command line tool, but how do you use a custom internal DNS server without modifying all your applications? One answer to this question is Dnsmasq.

I’m not explaining Consul here, the above mentioned introduction does a good job of stepping through the setup. The following assumes you have installed and started consul.

Installation and configuration

I’m running these examples on an Ubuntu 14.04 machine, but dnsmasq should be available and packaged for lots of different operating systems.

apt-get install dnsmasq

Once installed we can create a very simple configuration.

echo "server=/consul/" > /etc/dnsmasq.d/10-consul

All we’re doing here is specifying that DNS requests for consul services are to be dealt with by the DNS server at on port 8600. Unless you’ve changed the consul defaults this should work.

Just in case you prefer Puppet their is already a handy dnsmasq module. The resulting puppet code then looks like this.

include dnsmasq
dnsmasq::conf { 'consul':
  ensure  => present,
  content => 'server=/consul/',


The examples from the main documentation specify a custom DNS server for dig like so:

dig @ -p 8600 web.service.consul

With Dnsmasq installed and configured as above you should just be able to do the following:

dig web.service.consul

And now any of your existing applications will be able to use your consul instance for service discovery via DNS.