ldap user creation is broken

[bjo81]

According to the ldap_entry docs, at least on Ubuntu 16.04 adding a LDAP user should work:
The default authentication settings will attempt to use a SASL EXTERNAL bind over a UNIX domain socket. This works well with the default Ubuntu install for example, which includes a cn=peercred,cn=external,cn=auth ACL rule allowing root to modify the server configuration

But it fails due to lacking superior knowledge:
UNWILLING_TO_PERFORM: {'info': 'no global superior knowledge', 'desc': 'Server is unwilling to perform'}

[bjo81]

Wrong dn, we should use dc=nodomain which is standard on such an installation. But now we get:
{'info': 'no write access to parent', 'desc': 'Insufficient access'}