A typical vCloud computing environment consists of multiple layers (IaaS, PaaS, and SaaS, possibly others). Based on business requirements, every customer chooses how to implement the vCloud stack. Options include creating a private vCloud, using a public vCloud provider, or creating a hybrid vCloud model in which both private and public vCloud resources are used. The enabler for this flexibility is the ability of an organization to guarantee availability and performance at every vCloud layer. This is achieved by signing SLAs externally with service providers, or for a private vCloud, creating SLAs with internal user organizations and supporting OLAs with the IT organization.