Platform-as-a-Service Providers

A overwhelming amount of attention and resources has been focused on Infrastructure-as-a-Service (IaaS) clouds. IaaS clouds are in a sense more flexible but requires considerably more setup and configuration than Platform-as-a-Service (PaaS) clouds. IaaS clouds can serve both for webapp hosting as well as Hadoop-style cluster computations. PaaS clouds are clearly targeted at webapp hosting. PaaS cloud hosts usually provide a wide variety of supporting services (e.g., payment gateways, monitoring, CRM) to help developers focus on core business logic, but often businesses have found out that PaaS is too restrictive, requiring one to give up too much control over the webapp architecture. In particular, PaaS often requires one to select from a limited set of data stores and load balancers. Sometimes, PaaS requires webapps to be written against a particular proprietary API, potentially a restricted and even proprietary data store. This would make something rather simple such as a deploying a Wordpress site a non-starter.