Apache Whirr is a set of libraries for running cloud services on-demand in a cloud-neutral way. It provides common APIs and defaults for deploying clusters running Hadoop, Cassandra, HBase, and Zookeeper on EC2 and Rackspace. Whirr configurations allow deploying typical clusters with a single command. It is being developed further to support private clouds and new services, and to integrate with Hudson for testing fault injection scenarios on small test clusters.