I suppose it's good practice to put something here so people understand what this is... So here it is.
This is a docker image for https://sourceforge.net/p/ddclient/wiki/Home/
There's a docker-compose file to start this easily.
cd /path/to && git clone https://github.com/davidhockey22/ddclient_docker_simple.git docker-compose up ddclient
If you want to do it the manual way, I suppose you could also run something like
docker run -v /path/to/config:/etc/ddclient davidhockey22/ddclient_docker_simple
You could also include some environment variables to make change stuff in the image if you want.
CONFIG_DIR /path/to/config CONFIG_FILE ddclient.conf
It should just work this way but if it doesn't, put an issue in or fork this and fix it.