PAAS vs IAAS
Cloud computing is a style of computing in which resources are made available over the internet. Most often these resources are extensible and highly visualized resources and they are provided as a service. Cloud computing is broken down in to few different categories based on the type of service provided. PaaS (Platform as a Service) is the category/application of cloud computing in which the service providers deliver a computing platform or a solution stack to their subscribers over the internet. IaaS (Infrastructure as a Service) is the category of cloud computing in which the main resources available as a service are hardware infrastructure.
What is PaaS?
PaaS is the category/application of cloud computing in which the service providers deliver a computing platform (a hardware architecture and a software framework) or a solution stack (computer subsystem needed to run a software). This makes it possible for the subscribers to deploy an application without having to buy and manage the necessary software and hardware requirements. The responsibility of maintaining the necessary hardware, operating systems, helper applications and databases is the sole responsibility of the service provider. The PaaS subscribers can make use of the delivered platform to build and ultimately deliver web applications and services. PaaS services typically offer complete set of facilities for designing, developing, testing and deploying applications to team collaboration, web service and database integration, version control and configuration management of software. All these facilities are usually available as a single integrated development environment making it very convenient to the developers or the users. Four popular types of PaaS are Add-on, Stand alone, delivery-only and open platform PaaS.
What is IaaS?
IaaS, sometime know as Hardware-as-a-Service (HaaS), delivers equipments needed to cater operations, storage, hardware and networking components (including servers) to their subscribers, over the internet. In other words, IaaS deals with offering (in a virtual, on demand manner) computing resources like servers, storage and other low-level n/w and h/w components. It is the sole responsibility of the service provider to house, run and maintain all the hardware resources. Subscriber will pay on a per-use basis based on the utility computing billing model without having to buy those infrastructure resources. The subscriber will get the feeling of acquiring network/server resources in zero time and space. Popular commercial IaaS service providers are GoGrid and Amazon’s EC2.
What is the difference between PaaS and IaaS?
Even though, PaaS and IaaS are two applications/categories of cloud computing, they have their key differences. PaaS is the category of cloud computing in which the service providers deliver a computing platform or a solution stack, while IaaS focuses on delivering computer infrastructure such as hardware resources available over the internet. Important difference between these two services can be identified from the type of subscribers. PaaS is typically used by application developers, while IaaS is used by network architects. In other words, PaaS provides a mechanism to develop applications whereas IaaS provides only the infrastructure necessary to run the code developed by application developers. Therefore, IaaS offerings by themselves may not be useful without a suitable PaaS offering running on top of it. PaaS can be thought of as an additional layer of abstraction on top of IaaS. If you already have a working code as a package then an IaaS is more suitable, while if you do not have a software solution in place (or the current available solution is too expensive) and you want to build a solution from the scratch, subscribing to a PaaS is the way to go.