I am currently developing a php-application for a charity organization and I am now in the stage of defining the deployment practices.
Our application is using both Zend
You said that you have a claster. We're in the same position and we use ZF and Doctrine. This is how we solved the problem:
This is far from ideal but it works fine for us. Hope that helps.
Links:
Apache Ant
LiquiBase
If you have some questions please let me know so I can update the answer.t