A key architect of the Microsoft datacentre strategy, James Hamilton,  has jumped ship and joined rival Amazon Web Services (AWS).

Hamilton, a former datacentre futures architect at Microsoft, has left the company to become a vice president distinguished engineer at AWS.

Amazon did not say specifically what Hamilton's role would be, saying only that he will "start putting his expertise" to work in "designing and deploying systems that are secure and that scale reliably and cost-effectively" at AWS beginning in January.

Hamilton, who disclosed that he had left Microsoft on his home page, had been instrumental in designing the company's current and expanding datacentre strategy as part of the datacentre futures team, which is responsible for datacentre efficiency, speed of deployment and reliability.

Hamilton also blogged about his impending move on his Perspectives blog, saying that he has had a "super-interesting time at Microsoft" and that leaving the company is "tough."

Prior to joining the datacentre futures team, Hamilton was an architect on the Live Platform Services team. Before that he was general manager for Microsoft Exchange Hosted Services and also worked in the SQL Server database group.

Microsoft has been busily adding new datacentres to support its burgeoning software-as-a-service and cloud-computing strategies. This year the company put a significant amount of investment into its Live search engine and Windows Live set of services, among other offerings, specifically to compete with AWS and also Google.

In October Microsoft revealed one of its most significant offerings to date to advance its cloud-computing strategy, the Windows Azure Services Platform. This application-development platform and infrastructure is entirely hosted in by Microsoft.

In the meantime, AWS, the Amazon.com pioneering cloud-computing subsidiary, continues to expand its own footprint. Last week, the company revealed its first pay-as-you-go application and service-delivery in Europe.

Related articles:

Capgemini and Amazon bond in the cloud