Few months back I was asked by stratoscale to provide my comments on the three most common cloud computing models viz, Infrastructure as a Service (IaaS), Platform as a Service (PaaS) and Software as a Service (SaaS).
Here is my take on the three models (re-posting from the original article).
“IaaS is the most flexible and customizable of the available cloud services. For many users, IaaS is the start of their cloud journey. A user is free to choose the right options for computing, network and storage services based on requirements. Furthermore, the user has a very high degree of control over the environment. But too much flexibility might sometimes be overwhelming for users, and this is precisely the problem with IaaS. For example, AWS provides so many options for EC2 that for many users, selecting the right one can be daunting. Additionally, provisioning and Ops management of the IaaS instances is the end-user’s responsibility and infrastructure management is non-trivial. IaaS is also more costly as pricing is based on compute units.
PaaS shortens the time and resources required to develop applications due to the availability of add-ons or out-of-box functionalities. Examples of such add-ons are application aware load-balancing, authentication and authorization, big data services and analytics, and so on. Consequently, leveraging PaaS results in faster time to market. The infrastructure aspects of the application (such as resource allocation, capacity planning, environment creation, and so on) are handled by the PaaS provider, thereby letting the end-user to focus on their core business. However, overuse of PaaS add-ons or out-of-box functionalities can result in lock-in, which might create migration issues. PaaS is also limited by the supported language runtimes.
SaaS is the most effective of cloud services because it reduces the overall software acquisition and related infrastructure costs. There is no need to worry about the management of the application and its hosting infrastructure and no vendor lock-in (one can always decide to move to a competing product). Furthermore, integration with other SaaS offerings is relatively easier and adds to the overall value of leveraging SaaS. SaaS also results in a loss of control over the upgrade lifecycle and application configuration, testing and configuration parameters. And finally, depending upon the number of SaaS offerings being used, management and governance can also be a challenge, because each offering comes with it’s own management console.”
Interested to hear what other cloud experts are telling about the three models !! Read the full article here –http://www.stratoscale.com/resources/article/iaas-paas-saas-the-good-bad-ugly/