This article is also available in our new Knowledge Base: AWS Cloud Formation Does Not Support Template Upgrades with Zend Server / RDS Modifications
Zend Server on AWS
When you edit templates, refer from changing RDS and Zend Server related configuration.
To modify the MySQL password for Zend Server user, if a must, you can edit zend_database.ini on one node, apply the changes to cluster DB - this will break operations with the UI and components. Then, login to MySQL using a client and change the zend user password according to what you changed in zend_database.ini.
To modify Admin login password, use the UI or command line tool with the /usr/local/zend/bin/gui_passwd.php command.
If you already modified the above using the template, you will need to delete ZSSESSID/ZS6SESSID cookie from your browser, and login again.