kinit error with systemd

[steve]

When trying to get Kerberos tickets, we get an error that the directory
does not exist e.g. 
as root:
 kinit Administrator
 kinit: Credential cache directory /run/user/0/krb5cc does not exist
 while getting default ccache
 
 If I now create the directory:
 /run/user/0
it works fine. 

I'm not sure whether this is a kinit problem or a systemd problem as
the /run/usr/$UID directory is only produced when $UID logs in. 

Previously, the cache was produced in /tmp which is _always_ available.

What are we supposed to do to automount a kerberised cifs share where
root will never be logged in?

Thanks,
Steve