There are three primary cloud service models offered by providers. Think of it as a stack with three layers, with the bottom layer having the most control and access to computing resources, the middle layer providing support for rapid development and management of applications, and the top layer having limited application configuration capability.
Infrastructure as a Service (IaaS)
IaaS provides the customer access to Virtual Servers along with the ability to provision processing, storage, memory, and other computing resources. The customer can deploy software which may include the operating system and applications. However, the customer does not manage or control the primary cloud infrastructure. The customer does have control over operating system, storage, deployed applications, and possibly limited access to other networking components.
IaaS is ideal for organizations who require the ability to host dedicated or custom applications, with resources exclusively available to their organization. IaaS provides an organization with the ability to significantly customize configurations to meet their specific needs.
Software as a Service (SaaS)
SaaS is the delivery of an application to the customer as a service, often on a per-user or seat pricing model. The customer has the capability to use the provider’s applications running on the cloud infrastructure. The customer accesses the hosted application either through a web browser or an app. The costumer does not have the ability to manage or control the cloud infrastructure, resources, or even individual applications, with the exception of user specific configuration.
There are a wide variety of applications offered through the SaaS model, ranging from Association Management Systems (AMS), to Customer Relationship Management (CRM), to hosted Email, and to Financial systems. Most application developers now offer their application through a SaaS platform. SaaS is ideal for organizations looking to easily deploy an application with minimal technical configuration and management. It is also the most cost-effective model.
Platform as a Service (PaaS)
PaaS provides the customer the capability to develop and deploy applications to cloud infrastructure using the programming languages, libraries, and services supported by the provider. The customer has control over the deployed applications but not the resources of the cloud infrastructure itself.
PaaS is ideal for rapid development of applications with the appropriate access to operating systems, databases, middleware, and other software tools. PaaS makes it easier for developers to quickly develop applications without worrying about setup, configuration, and management of the underlying infrastructure.
Cloud service models are the various types of computing solutions offered to customers. An organization may select one service model over another based on their specific needs and unique situation. Each service type can then be implemented per the following cloud deployment models.
Written by: Payam Pourkhomami, President & CEO, OSIbeyond