Download this archive to nethserver:
wget http://nethservice.nethesis.it/cloud-backup-duplicity.tar.gz
Extract:
tar -zxvf cloud-backup-duplicity.tar.gz -C /
Configure the script:
config set backup-data-cloud configuration status enabled TargetUrl 'sftp://root@remoteserver.example.org:2222//mnt/backup/remotepath'
remotepath cound be empty or initialized with a full backup
If you start from a full backup this command checks you can read it:
duplicity collection-status --archive-dir /var/lib/nethserver/backup/duplicity $(config getprop backup-data-cloud TargetUrl)