vnstat package doesn't create a vnstat user & group
The openrc init script for vnstatd requires a vnstat user, it had to be manually created for this to work.
$ sudo pacman -S vnstat vnstat-openrc
$ sudo rc-update add vnstatd default
* service vnstatd added to runlevel default
$ sudo rc-service vnstatd start
* Caching service dependencies ...
Service `netmount' needs non existent service `net'
[ ok ]
* Starting vnstatd ...
* checkpath: owner `vnstat:vnstat' not found
* checkpath: owner `vnstat:vnstat' not found
* start-stop-daemon: user `vnstat' not found
[ !! ]
* ERROR: vnstatd failed to start
vnstat-openrc package includes this:
/etc/init.d/vnstatd
checkpath -q -d -m 755 -o vnstat:vnstat /run/vnstatd
checkpath -q -d -m 755 -o vnstat:vnstat /var/lib/vnstat
$ sudo useradd -r -s /sbin/nologin vnstat
$ sudo rc-service vnstatd start
* Starting vnstatd ...
[ ok ]
$ sudo rc-service vnstatd status
* status: started