Thank! Just updated from 16.04 to 18.04.4 LTS and ran into this. If anyone comes across this running Ubuntu 17.04+:
$ sudo nano /etc/systemd/resolved.conf and change #DNSStubListener=yes to DNSStubListener=no (make sure you uncomment the line).
$ sudo service systemd-resolved restart
EDIT: Spoke too soon. This DOES allow the container to boot up, but it breaks DNS for the host.
EDIT 2: Okay, here are the steps that work for ME. You may have different needs.
$ sudo nano /etc/systemd/resolved.conf (make changes based on above)
$ sudo service systemd-resolved restart
$ sudo systemctl disable systemd-resolved.service
$ sudo systemctl stop systemd-resolved
$ sudo rm /etc/resolv.conf
$ sudo shutdown now -r
I haven't put much thought into this. You can probably actually skip the first two steps (I don't have a good way to verify), however following the above steps fixed it so that (1) the container will boot, and (2) the host can resolve domain names.