I struggled a bit with NConf on CentOS 7.
Following the NConf example configuration files, in order to perform deployment, the default temporary location is /tmp
So, it was supposed that temporary files goes to /tmp, but no file was here.
The right location is /tmp/systemd-private-<randomchars>/tmp/
So, if you want things to work, select another temp dir: neither /var/tmp is a good place (there is a systemd-private directory)