The PaaS delivery model represents a predefined, ready-to-use environment typically comprised of already deployed and configured IT resources. Specifically, PaaS relies on (and is primarily defined by) the usage of a ready-made environment that establishes a set of pre-packaged products and tools used to support the entire delivery life cycle of custom applications.

Common reasons a Cloud consumer would use and invest in a PaaS environment:

• The Cloud consumer wants to extend on-premise environments into the Cloud for scalability and economic purposes
•  The Cloud consumer uses the ready-made environment to entirely substitute an on-premise environment
• The Cloud consumer wants to become a Cloud provider and deploys its own Cloud services to be made available to other external Cloud consumers

By working within a ready-made platform, the Cloud consumer is spared the administrative burden of setting up and maintaining the bare infrastructure IT resources provided using the IaaS model.