A very simple docker image with a canned configuration for mesos-dns. Deploy this on as many nodes in your ACS cluster as you please.
Usage is simple, just run the container. Because it assumes you're using ACS it will look for mesos masters on 10.0.0.5 - 10.0.0.19 (inclusive). If this matches your configuration then you don't need to apply any configuration. Simply use marathon to run the container on every slave with bridged networking and port 53 (tcp and udp) open.
Once you have the containers running in docker with a bridged network on all nodes in your cluster you can either put 127.0.0.1 in /etc/resolv.conf or you can run all your containers with the --dns=127.0.0.1 option.