If a website required domain
sub.domain.com to point to a folder inside main site webroot, we can do it by:
1). Open
/var/www/vhosts/domain.com/subdomains/sub/conf/vhost.conf in editor.
2). Add to it the following contents (for sub.domain.com):
DocumentRoot /var/www/vhosts/domain.com/httpdocs/sub
<Directory /var/www/vhosts/domain.com/httpdocs/sub>
<IfModule sapi_apache2.c>
php_admin_flag engine on
php_admin_flag safe_mode off
php_admin_value open_basedir "/var/www/vhosts/domain.com/httpdocs:/tmp"
</IfModule>
<IfModule mod_php5.c>
php_admin_flag engine on
php_admin_flag safe_mode off
php_admin_value open_basedir "/var/www/vhosts/domain.com/httpdocs:/tmp"
</IfModule>
Options -Includes -ExecCGI
</Directory>
3). Then reconfigure Plesk by using command
# /usr/local/psa/admin/bin/websrvmng -a