Although I’m no fan of anything/everything as a service (XaaS), mainly due the fact that it has been overused by marketing teams to define whatever they are trying to promote as-a-service.
The original three as-a-service definition Software (SaaS), Platform (PaaS) and Infrastructure (IaaS) provide a clearer understanding of what most people still refer to as the cloud. So to expand on our previous Cloud Computing Overview post by taking a quick look at these services.
Infrastructure as a Service (IaaS)
In IaaS the OS, Storage and Network or infrastructure are all abstracted away from the end user. Leaving the end user with the flexibility to install and configure a server as necessary without any concern over space. Resources such as block and file-based storage, firewalls, load balancers are all included in IaaS. This service lines up closely to public and private cloud offerings like Amazon Web Services (AWS) EC2 or S3, Microsoft Azure or private solutions such as OpenStack.
Platform as a Service (PaaS)
PaaS takes this one step further by abstracting everything in IaaS, plus hiding the middleware required to build the solution. The infrastructure and the platform are hidden by providing a preconfigured operating system and platform such as a web server, programming execution environment or database. So instead of having to build everything from scratch a high level interface is made available to the consumer.
Software as a Service (SaaS)
Finally SaaS takes all of the abstraction of PaaS, plus the application is abstracted. In this instance the user is being delivered the software in full. They don’t have to install or update anything, everything is taken care of. Some examples of this would include Microsoft Office 365 or Gmail.
In our cloud computing overview we came to the conclusion that the cloud is nothing more than a self provisioned on-demand solution that is abstracted away from the end user. However looking at X-as-a-Service we can see that not all clouds are indeed the same.