Real simple Docker for running a udhcpd server
docker run -d --net=host -p 67:67 -p 67:67/udp -p 68:68 -p 68:68/udp --name=dhcpd -v /path/to/docker/dhcpd:/data jedimonkey/udhcpd
It will create a udhcpd.conf first time in your mapped volume if one doesn't already exist.
Using both host networking and ports currently - seems to not complete the DHCP process without host networking. Will try to fix it later.