CloudStack was originally developed by Cloud.com, formerly known as VMOps. In May 2010, Cloud.com released most of CloudStack as free software under the GNU General Public License, version 3 (GPLv3). They kept about 5% proprietary. Cloud.com and Citrix both supported OpenStack, another Apache-licensed cloud computing program, at its announcement in July 2010.
Citrix purchased Cloud.com on July 12, 2011, for approximately $200 million. In August 2011, Citrix released the remaining code under GPLv3 and continued moving towards more open processes. In February 2012, Citrix released CloudStack 3.0. Among other features, this added support for Swift, OpenStack's S3-like object storage solution. In April 2012, Citrix donated CloudStack to the Apache Software Foundation (ASF), where it was accepted into the Apache Incubator; Citrix changed the license to the Apache License version 2. As part of this change, Citrix also ceased their involvement in OpenStack. On November 6, 2012, CloudStack 4.0.0-incubating was announced, the first stable release after joining ASF. On March 20, 2013, CloudStack graduated from Apache Incubator and became a Top-Level Project (TLP) of ASF. The first stable (maintenance) release after graduation is CloudStack 4.0.2.
The minimum production installation consists of one machine running the CloudStack Management Server and another machine to act as the cloud infrastructure (in this case, a very simple infrastructure consisting of one host running hypervisor software). In its smallest deployment, a single machine can act as both the Management Server and the hypervisor host (using the KVM hypervisor).
Multiple management servers can be configured for redundancy and load balancing, all pointing to a common MySQL database.