Microsoft today released a preview of Azure Stack, a version of the Azure services and infrastructure that you can run in your own datacenters.

Azure Stack was announced at the Ignite conference last year. It's an Azure-flavored counterpart to OpenStack, offering enterprises the ability to use the same services and management systems for both local on-premises deployments and true cloud deployments.

Currently, the Azure Stack offers only a subset of Azure services, and it runs on just a single server. Its full release is planned for the fourth quarter, but even this will not have parity with the full Azure service. Microsoft's aim for the initial release is to provide all the major parts to support deploying platform-as-a-service Web Apps and infrastructure-as-a-service virtual machines. It will also include components for storage and virtualized networking. The Azure Portal front-end for managing the service will also be included.

As such, there will be plenty of things missing, such as SQL databases and machine learning. Which of these capabilities are added, and when, will be determined in part by customer demand.