Usually, the *samba* role is deployed as a dependency of the *winbind*
role, which explicitly sets `samba_security` to `ads`. The new
*fileserver* role also depends on the *samba* role, but it does NOT sett
that variable. This can cause `smb.conf` to be rewritten with a
different value whenever one or the other role is applied.
Explicitly setting the `samba_security` variable at the group level
ensures that the value is consistent no matter how the *samba* role is
applied. Since all domain member machines need the same value,
regardless of what function they perform, this is safe.
Dustin
4aded1e75c