Brooks, Good news. I have an example ( https://github.com/brianredbeard/memcache-tools ) of just that which was written using CoreOS.
In this case you would have two containers with two systemd units.
Memcache.service unit:
[Unit]
Description=My Memcached Server
Requires=docker.service
After=docker.service
[Service]
ExecStart=/usr/bin/docker run --rm --name %n -t -i memcache
Worker.service unit:
[Unit]
Description=My worker container
Requires=Memcache.service
After=Memcache.service
[Service]
ExecStart=/usr/bin/docker run --rm --name %n -t -i --link memcache:memcache my_container
What this will do is take the first container named memcache and present a number of variables into my_container in the form: MEMCAHCE_PORT_11211_TCP_???, e.g.MEMCAHCE_PORT_11211_TCP_HOST & MEMCAHCE_PORT_11211_TCP_PORT which can then be consumed inside your program.
Take a look at the dump, load, and sample scripts as well as the Dockerfile and README.md in that example.