A base image for installing systemd on centos 7
docker pull lloydbenson/docker-centos-7-systemd
Note: Looking around I kept seeing references for removing fakesystemd. However, I never found such a package with the latest centos 7. Instead it was called systemd-container and systemd-container-libs. I remove these and install just standard systemd. You can build on top of this and just make sure you start /usr/sbin/init as the final thing and it will start up your services. You likely need --privileged=true in your run for this to be useful.