Naturally, a ZDC container is also equipped with software services. This being Zend Technologies, it's no surprise the container includes a PHP runtime, an instance of Zend Server (the full-fledged enterprise edition), and an instance of MySQL Server. Actually, it is more accurate to say the container has access to a MySQL Server instance. The capacities that a container can command from the MySQL instance are limited. Although you can create as many MySQL tables as you wish, you are limited to a single schema (database). Currently MySQL is the only database option, but support for MongoDB and others is likely to follow.
Zend Server is a Web application server augmented to support both the development and deployed execution of PHP applications. It is available in community and nonfree editions, both of which provide useful add-ons that include a general-purpose data cache, an execution optimizer that caches precompiled PHP byte code, a debugger, and more.
The enterprise edition adds to these an event monitoring system that lets you log the details of out-and-out errors (such as database errors), as well as potentially dangerous conditions (such as unusually high memory usage, slow query execution, and more) -- exceedingly useful in postmortem analysis. The enterprise edition also provides code tracing that can produce a profile of code execution paths. You can configure profiling to be triggered by specific events (for homing in on a particularly suspicious method) or enable profiling for the whole application. Developing your application in Zend Developer Cloud gives you all the advantages of a full-blown Zend Server installation.
These components are bonded together by what is referred to as the Zend Application Fabric. The Fabric is a PHP-friendly runtime environment that includes -- in addition to the services already described -- the Zend Framework (via Zend Server), as well as failover, load balancing, and scaling capabilities that provide cloud-friendly elasticity with minimal management overhead. Here, however, you find there are differences between the Zend Application Fabric of the ZDC environment and the Zend Application Fabric in a deployment environment.