When Gsutil is run manually by the shell, the full path is not required. So, the command gsutil rsync /var/www/BACKUP gs://mybucket is sufficient. However, the cron requires the full path. The path can be located with the command gsutil version -l This yields the output root@server:/var/www# gsutil version -l gsutil version: 5.21 checksum: 74f2cab932617e89e1a88b1b346339f7 (OK)