Could you explain a bit more how that works?
Afterwards, when my Django containers start, they pull their configuration from etcd using python-etcd. It will get the IPs and ports for the services, including Postgres, from etcd, and configure itself using that. Finally, it will keep these values in a dictionary. If these values ever differ from what's currently in etcd, then my Django app will send a signal to cause uwsgi to gracefully restart the Django app, so that it can reload itself with the new configuration.
For other Dockerized apps like nginx, I use kelseyhightower's confd-watch to monitor the etcd keys I'm interested in. confd-watch is great because it will use golang's text/template package to allow me to generate configuration files, like nginx.conf, with the values from etcd. So as these values get updated, so will nginx as confd-watch will force a graceful reload.
Hope that helps.
You could probably avoid the restart/reload by using skydns (https://github.com/skynetservices/skydns), it is a local dns service built on top of values in etcd. You can configure your django app to access the other service containers by dns name and it will be translated to the correct ip all the time.