Hi,
I assume you created the folder manually like described here. In this case it should be added to backup-data customization to be included in hotsync.
Shared folders created with the web UI are covered by hotsync because the shared folders in /var/lib/nethserver/ibay are included in backup-data by default.
Hotsync uses rsync and should do the job, you do not need a separate rsync script.
This way same IP, hostname and NSDC container are used on the promoted slave and therefore NS AD should be accessible without problems.