What is CloudStack? Free (as in speech, and beer) Infrastructure as a Service implementation that supports multiple hypervisors, complex network and firewall configuration, high-availability, and complex multi-tenant offerings.
What do IaaS Cloud Platforms really do? <ul><li>Manage HA
High Availability <ul><li>CloudStack, upon noticing an instance failing will attempt to restart the node, and failing that will create a new instance on a different piece of hardware in the cluster.
Robust API CloudStack is replete with a robust RESTful API (output in XML or JSON) Allows external applications such as monitoring to perform actions such as spinning up new instances in response to load. Allows you to loosely couple external applications such as billing and PaaS to CloudStack.