I work in a company which is about to migrate most applications from in-house custom built Java/Tomcat applications to Drupal. Due to company policies, applications and websites need to run on in-house servers. This means that we need infrastructure for Drupal (PHP/MySQL) applications.

This must have been solved a million times already. I believe this is what web-hosting companies does every day. Even though we work on a much smaller scale than web-hosting companies, i assume it would make sense to look at the task as if we're going to have an internal small-scale web-hosting company. This means that the guys in IT operations could be "responsible" for "offering" web-hosting, while developers could use these "services".

We have three environments; dev(elopment), test and prod(uction). It would make sense that developers could log in to a system and create/edit/delete dev and test sites as they'd like. Production sites should be available through the same system, but only available to IT ops.

We need to work with clusters of web servers, meaning that an administration system should be capable of creating/editing/deleting sites across multiple servers.

I know there's no "this is it" answer to my question; but what would be a good place to start to get going with this? Apart from the actual hardware, what would be a good administration system for this?