There seems to be tons of different ways people have been able to run systemd services within Docker containers. The latest example of direct advice I've found is to run Docker with --volume=/sys/fs/cgroup:/sys/fs/cgroup:ro --cap-add=SYS_ADMIN --security-opt=seccomp:unconfined. However, it still just failsfails:
Error: Could not start Service[ntpd]: Execution of '/usr/sbin/systemctl start ntpd' returned 1: Failed to connect to bus: No such file or directory
What is the absolute minimum I need to do to get simple services running under systemd 231 on a docker 1.12.1 container with an up-to-date Arch Linux distribution?