In coding an equivalent to Heat's Wordpres + MySQL app on same instance we found that after the scripts configured the wordpress app it restarted the web server (apache) that was hosting it to pick up the new settings. This basically voided TOSCA's approach to nodes and allowing the orchestrator to do these things.

Here is the WordPress config scripts

sed -i "/Deny from All/d" /etc/httpd/conf.d/wordpress.conf
sed -i "s/Require local/Require all granted/" /etc/httpd/conf.d/wordpress.conf
sed -i s/database_name_here/db_name/ /etc/wordpress/wp-config.php
sed -i s/username_here/db_user/ /etc/wordpress/wp-config.php
sed -i s/password_here/db_password/ /etc/wordpress/wp-config.php
systemctl restart httpd.service

Ideally, there should be a TOSCA way to do this.