Understanding the Cloud Computing Stack-SaaS_PaaS_IaaS

The Cloud Computing Stack

Cloud Computing is often described as a stack, as a response to the broad range of services built on top of one another

• On-demand self-service. The ability for an end user to sign up and receive services without the long delays that have characterized traditional IT
• Broad network access. Ability to access the service via standard platforms (desktop, laptop, mobile etc)
• Resource pooling. Resources are pooled across multiple customers
• Rapid elasticity. Capability can scale to cope with demand peaks
• Measured Service. Billing is metered and delivered as a utility service

The diagram below depicts the Cloud Computing stack – it shows three distinct categories within Cloud Computing: Software as a Service, Platform as a Service and Infrastructure as a Service.

• SaaS applications are designed for end-users, delivered over the web
• PaaS is the set of tools and services designed to make coding and deploying those applications quick and efficient
• IaaS is the hardware and software that powers it all – servers, storage, networks, operating systems

To help understand how these 3 components are related, some have used a transportation analogy;

By itself, infrastructure isn’t useful - it just sits there waiting for someone to make it productive in solving a particular problem. Imagine the Interstate transportation system in the U.S. Even with all these roads built, they wouldn’t be useful without cars and trucks to transport people and goods. In this analogy, the roads are the infrastructure and the cars and trucks are the platform that sits on top of the infrastructure and transports the people and goods. These goods and people might be considered the software and information in the technical realm.

Infrastructure as a Service

Infrastructure as a Service (IaaS) is a way of delivering Cloud Computing infrastructure – servers, storage, network and operating systems – as an on-demand service. Rather than purchasing servers, software, datacenter space or network equipment, clients instead buy those resources as a fully outsourced service on demand

Characteristics of IaaS

• Resources are distributed as a service
• Allows for dynamic scaling
• Has a variable cost, utility pricing mode
• Generally includes multiple users on a single piece of hardware

There are a plethora of IaaS providers out there from the largest Cloud players like Amazon Web Services and Rackspace to more boutique regional players.

Where IaaS Makes Sense

IaaS makes sense in a number of situations and these are closely related to the benefits that Cloud Computing bring. Situations that are particularly suitable for Cloud infrastructure include;

• Where demand is very volatile – any time there are significant spikes and troughs in terms of demand on the infrastructure
• For new organizations without the capital to invest in hardware
• Where the organization is growing rapidly and scaling hardware would be problematic
• Where there is pressure on the organization to limit capital expenditure and to move to operating expenditure
• For specific line of business, trial or temporary infrastructural needs

Where IaaS May Not be the Best Option

While IaaS provides massive advantages for situations where scalability and quick provisioning are beneficial, there are situations where its limitations may be problematic.

• Where regulatory compliance makes the offshoring or outsourcing of data storage and processing difficult
• Where the highest levels of performance are required, and on-premise or dedicated hosted infrastructure has the capacity to meet the organization’s needs

By:- Mr.L1nxr00t