Drupal

Agile development and deployment workflow

This series describes a development and deployment process optimized for the needs of software-as-a-service in terms of cost structure, agility, staging and test requirements.  The resulting system will tolerate the failure of a local hard drive and crashes of a machine - physical or virtual.  Offering good performance / low cost via Amazon's EBS and EC2 services, the system will provide the ability to rollback changes both on the deployed and development system (independently or together) using Subversion.

You can enjoy instantaneous feedback when you are developing code without affecting existing users of your website by using a two machine development and deployment lifecycle.  Deployment can be a 5 second experience (as opposed to 5 minutes) using AppZero technology.

I have tried a number of lifecycle workflows for the development and deployment of Drupal websites. In this series, I will describe a two machine approach involving a local development and test machine and a deployment machine. Deployment of files will use the Subversion Version Control System; the local machine is Windows to make tools like Photoshop convenient to use; the deployment machine is a Windows machine from EC2; and we will use Apache, Drupal, and MySql.

The one-machine approach, topologically simplest, involves developing directly on the deployed machine on the Internet. I've found this approach, while seemingly simple, to have two serious deficiencies:

• developing a new feature for a site can often involve accidentally breaking existing functionality or look-and-feel. This topology makes it difficult to evolve a site without showing the public every intermediate change.

• tools like Photoshop  are not convenient to use on a remote basis and ftp'ing files back and forth is a cumbersome process. Even text editing on a remote machine incurs painful latencies.

For these two reasons, I advocate at least a two machine approach. This allows you to develop on your local machine, disconnected from the Internet if necessary, with all the tools you like, and deploying when you desire. Of course, in a two machine topology approach, deployment agility becomes paramount. The difference between 5 seconds to deploy and 5 minutes makes the difference between wonderful and painful.