Until now the whole book has been about development. However, this is only half the story. The real complexity begins after that, when your application goes live, and even before that during the testing phase.

Usually, this process is split apart from the developer, as another department or at least other people than the developers perform the deployment. However, this chapter is targeted at both groups, developers as well as system administrators. It is generally a good idea to try and merge the groups a little closer in order to be able to cooperate better and understand, why each groups prefers doing things differently.

Testing is another important issue. Test-driven development in small and agile teams is getting more common. This requires continuous integration systems in order to have constant information about the state of your code. These continuous integration systems help you to determine whether your code is ready to be deployed, and whether you have written enough tests. Two recipes are about making Play adapt to continuous integration, either using Jenkins (formerly Hudson) or using the Calimoucho application, a Play application itself which runs all tests of another Play application.

This chapter does not only include information on how to roll out a Play application, it also includes information on what the developer has to think about when an application goes from desktop development to a complex multi-node production setup. The complexity of switching to a complex production setup should be known by the developers as well as the system engineers.