Leinwand was once a venture partner at Panorama Capital and founded Vyatta, an open source networking company. He was also the CTO of Digital Island, a content delivery network and CEO of Proficient Networks. Leinwand was one of the key people behind Zynga’s shift away from Amazon’s cloud service to Zynga’s homegrown Z-cloud.

Zynga has been losing senior executives at an alarming rate. Earlier this summer, the company lost about seven executives including Mike Verdu, Zynga’s former chief creative officer and Bill Mooney, who spearheaded the Farmville franchise. Zynga went public at $10 a share and hit an all time high of $14.69 a share in March 2012, but since then has been in a swoon. At close of trading on Friday, Zynga stock stood at $2.88 a share, giving company a market capitalization of $2.19 billion.

Disclosure: Leinwand was an occasional contributor on cloud & infrastructure related topics to our blog before joining Zynga.

Related research and analysis from GigaOM Pro:
Subscriber content. Sign up for a free trial.

• Cloud and data third-quarter 2012
• Amazon’s DynamoDB: rattling the cloud market
• Migrating media applications to the private cloud: best practices for businesses

“In early 2011, 80 percent of our [daily average users] were on Amazon, 20 percent on Z Cloud. By the end of the year that number flipped,” said Zynga’s CTO of infrastructure engineering Allan Leinwand. He will discuss this “flip” on Thursday at the Cloud Connect Conference in Santa Clara, Calif.

This, according to Leinwand, is a huge, innovative thing. “Moving 80 percent of our players off a public cloud onto private Z Cloud — that means we built capacity, data centers, infrastructure, storage, servers to handle the dramatic shift of workload,” he said.

As Zynga evolved, its standard practice was to launch games in the Amazon cloud and, as it better understood the associated workloads, move them in-house.  Last year, it felt confident enough to run more of the launches internally, and in June 2011, it launched CityVille Hometown in Z cloud.

In 2010, “we realized we needed to own the base and rent the spike,” Leinwand added. So returning more work to Amazon is always an option.

“We started building our launches in Amazon, and last year I said, when the slope of the line and workload was well understood, we brought the game back into Z Cloud — no one had done this cloudbursting thing in reverse before,” Leinwand added.

This is pretty impressive progress. Zynga brought up its first Z Cloud data center in the spring of 2011, and in March started migrating its games over.  The first game to launch all-out in Z Cloud was CityVille Hometown in June, and every game since has launched in the Z Cloud route, he said.

Z Cloud was built and optimized for the unique workloads of these interactive and graphics-intensive games. While Zynga has followed the Open Compute Project launched by Facebook last year and learned from that work, its data centers are not really Open Compute facilities.

“While we use a combination of OEM-provided compute, we also work with integrators and ODMs to build our own compute servers — they are not specifically Open Compute servers but are heavily influenced by that work,” Leinwand said.

“When we looked at Amazon and the number of players served, we were able to measure all that work in a discreet way.  We learned to build stuff for our games, to structure storage so that people can go from one game board to another fast, to put systems in memory to serve our needs. The upside of all that work, building the infrastructure to match workloads, the optimization of our storage platform, what we found is that for every three servers we had up in Amazon, we had one in Z Cloud.”

This is no knock on Amazon, he added. It’s just that Z Cloud is specially built for games while Amazon is a general purpose cloud flexible enough for trading, games and web commerce.

Leinwand would not comment on the number of data centers running Z Cloud or their locations.

Related research and analysis from GigaOM Pro:
Subscriber content. Sign up for a free trial.

• Federated clouds: for when one cloud isn’t good enough
• How direct-access solutions can speed up cloud adoption
• The promise of SDNs in the enterprise