https://coreos.com/docs/launching-containers/launching/getting-started-with-systemd/
http://www.freedesktop.org/software/systemd/man/systemd.unit.html
http://www.freedesktop.org/software/systemd/man/systemd.unit.html#Unit%20File%20Load%20Path
http://www.freedesktop.org/software/systemd/man/systemd.unit.html#%5BUnit%5D%20Section%20Options
http://www.freedesktop.org/software/systemd/man/systemd.unit.html#%5BInstall%5D%20Section%20Options
http://www.freedesktop.org/software/systemd/man/systemd.unit.html#Specifiers