A simple script to backup Plesk server and store data in a remote FTP

backup_ftp_plesk_server1.sh

#!/bin/bash
set -e

FTP_USER="ftp_user"
FTP_PASS="ftp_password"
FTP_HOST="ftp_host"

# REMOVE BACKUPS OLDER THAN 7 DAYS
FILES=$(lftp -e 'cd pleskbackup; cls --sort="date"; exit;' -u ${FTP_USER},${FTP_PASS} ${FTP_HOST})
if [ $(echo "${FILES}" | wc -l) -gt 7 ];
then
        FILE_TO_REMOVE=$(echo "${FILES}" | head -n1)
        lftp -e "cd pleskbackup; rm -f ${FILE_TO_REMOVE}; exit;" -u ${FTP_USER},${FTP_PASS} ${FTP_HOST}
fi
/usr/local/psa/bin/pleskbackup server --skip-logs --output-file=ftp://${FTP_USER}:${FTP_PASS}@${FTP_HOST}/pleskbackup/`date +%F`_full_psa_backup.raw

You have to manually install lftp:

apt install lftp for Debian/Ubuntu
yum install lftp for RedHat/CentOS