Zynga has an engineering post where they introduce their private cloud. This post is a bit old, but it provides good details on why Zynga chose to move out of AWS for its own private cloud.
Now, Zynga still does use AWS, but they are thinking from a business/financial perspective. Zynga has a hybrid cloud infrastructure, both public and private.
While our private cloud infrastructure has been growing quickly, Zynga also uses the AWS public cloud to fuel our rapid growth. Our use of AWS, while very important to our business, comes with an operating expense. Essentially, we have been trading monthly operating expenses against longer-term amortized capital expense. Yet, sometimes the pace of our growth forces us to make that tradeoff.
For example, when CityVille rapidly grew to millions of users in just six weeks, we had to grow our server infrastructure at a pace that kept up with and sometimes even outpaced this demand. In a strict capital expense model, we would have exceeded the supply chain of our equipment suppliers – the process of physically getting the number of servers ordered, shipped, delivered and implemented just takes too long. So, we traded the cost of operating expense in AWS for capital expense.
Zynga's cloud is compatible with AWS.
The zCloud is our private cloud that looks, feels, and operates in a similar fashion to the way that we use Amazon Web Services (AWS) Elastic Compute Cloud (EC2), our public cloud provider. As infrastructure that is private to Zynga, the ZCloud physically resides in our current datacenters and will expand as we grow our infrastructure over time.
Zynga has learned from its AWS operations and builds its own cloud with its own hardware.
While similar in functionality to AWS, our private zCloud is designed specifically for social games in terms of availability, network connectivity, server processing power and storage throughput. We have achieved these improvements by providing redundant power to each rack, state-of-the-art servers with high memory capacity, a fully non-blocking network infrastructure, the use of inline hardware-based load balancers and local disk storage.