Apache Whirr is an Incubator project which provides a way to run distributed systems - such as Hadoop, HBase, Cassandra, and ZooKeeper - in the cloud. Whirr provides a simple API for starting and stopping clusters for evaluation, test, or production purposes. Whirr is cloud neutral, so services may be run on a wide variety of cloud providers (such as Amazon EC2 or Rackspace), simply by changing a configuration property. This talk explains Whirr's architecture and shows how to use it.