SaaS, PaaS, IaaS
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When your business has made the decision to consider cloud services for your application or infrastructure deployment, it’s important that you grasp the fundamental differences between the core categories of cloud services available.
The cloud is a very broad concept, and it covers just about every possible sort of online service, but when businesses refer to cloud procurement, there are usually three models of cloud service under consideration, Software as a Service (SaaS), Platform as a Service (PaaS), and Infrastructure as a Service (IaaS). Each has its own intricacies and hybrid cloud models, but today we’re going to help you develop an understanding of the high-level differences between SaaS, PaaS, and IaaS.
In some ways, SaaS is very similar to the old thin-client model of software provision, where clients, in this case usually web browsers, provide the point of access to software running on servers. SaaS is the most familiar form of cloud service for consumers. SaaS moves the task of managing software and its deployment to third-party services. Among the most familiar SaaS applications for business are customer relationship management applications like Salesforce, productivity software suites like Google Apps, and storage solutions brothers like Box and Dropbox.
Use of SaaS applications tends to reduce the cost of software ownership by removing the need for technical staff to manage install, manage, and upgrade software, as well as reduce the cost of licensing software. SaaS applications are usually provided on a subscription model.
PaaS functions at a lower level than SaaS, typically providing a platform on which software can be developed and deployed. PaaS providers abstract much of the work of dealing with servers and give clients an environment in which the operating system and server software, as well as the underlying server hardware and network infrastructure are taken care of, leaving users free to focus on the business side of scalability, and the application development of their product or service.
As with most cloud services, PaaS is built on top of virtualization technology. Businesses can requisition resources as they need them, scaling as demand grows, rather than investing in hardware with redundant resources.
Examples of PaaS providers include Heroku, Google App Engine, and Red Hat’s OpenShift.
Moving down the stack, we get to the fundamental building blocks for cloud services. IaaS is comprised of highly automated and scalable compute resources, complemented by cloud storage and network capability which can be self-provisioned, metered, and available on-demand.
IaaS providers offer these cloud servers and their associated resources via dashboard and/or API. IaaS clients have direct access to their servers and storage, just as they would with traditional servers but gain access to a much higher order of scalability. Users of IaaS can outsource and build a “virtual data center” in the cloud and have access to many of the same technologies and resource capabilities of a traditional data center without having to invest in capacity planning or the physical maintenance and management of it.
IaaS is the most flexible cloud computing model and allows for automated deployment of servers, processing power, storage, and networking. IaaS clients have true control over their infrastructure than users of PaaS or SaaS services. The main uses of IaaS include the actual development and deployment of PaaS, SaaS, and web-scale applications.
