Cloud, SaaS, PaaS, IaaS… Basic concepts
This year I visited the Network Simo. One of those invited to speak on “Cloud Computing” was Javier Salcedo, chief of Arsys Cloudbuilder project. Javier made a presentation on how the roles played by each of the providers within the “cloudcomputing” are divided. I really liked this presentation because it seemed very clear and I have not seen anywhere. In the graph below try to explain this as he did:
Looking at this graph seems easy to delimit and define what the “cloud computing” is, but I think it is a term too new and abstract to define and delimit it. The definition more “standard”and that includes almost everything, that I consider “cloud”, is: “… all those services that reside on ‘Internet’ and are accessible from any terminal …”. This chart identifies the different roles of the “cloud” commercial that now exists.
SaaS: Software as a Service, the services are reaching the end user. To access these simply identified by username and password in most cases. The payment for the use ofthese services is usually by subscription, in some cases only pay what you use. The best way to identify them is by making an example such as Gmail, GoogleDocs, Dropbox …most of these applications have free versions, depending on the type of service will belimited in one aspect or another. If you need to exceed this limit or any additional service is the time to start paying.
PaaS: Platform as a Service, are software platforms for cloud. These platforms offer Frameworks to program in some language (provider dependent), packaging the application and bind to your provider account. To explain better, the process would be: I download the Framework of the supplier, I make the application, I pack and get it on the cloud. When uploading I have to specify what kind of machine I want to run my application and determine the scale at times of peak (if the provider becomes available for this.) Some PaaS do this transparently, I mean, payment in PaaS is always for use, if you normally have 10 clients, they billed us what the 10 clients consume at price set, and if we have 100 clients they billed us what the 100 clients consume . Examples of PaaS are GoogleApp Engine, Microsoft Azure, …
IaaS: Infrastructure as a Service, as in the previous case, the provider bill us for use. What gives us the supplier in this case are virtual machines, whether Linux, Windows or other operating systems. We must install our applications on them, creating the architecture for the autoscaling, load balancers, etc. IaaS examples are AmazonWeb Services, Cloudbuilder …
Later we will explain the criteria for choosing one model or another.