Based on abstraction

The underlying principle of cloud is abstraction; how it is abstracted determines a lot of its feature sets and behavior. However, this aspect of the cloud is little-known and often ignored. It only becomes evident when dealing with different kinds of clouds from different providers. 

We shall delve into the details and nuances. For starters, these are:  

• Service down clouds 
• Infrastructure up clouds 

To understand these better, let's take a look at the following stack, (which is used to run an application). The stack assumes a virtualized infrastructure being used to run the application.

In the event of an application running on bare-metal, the Virtual Machine and the Hypervisor layers will be absent, but the remainder of the stack will still be in play. 

In traditional IT businesses, different teams manage different aspects of this stack. For example, the Infrastructure management team manages the underlying hardware and its configuration, the Virtualization team manages the Virtual Machine and the Hypervisor, the Platform team manages the Middleware, the Operating System teams manage the Operating System and finally the Application team will manage the Application and the data on top of the stack. 

Now, from the perspective of the Infrastructure management team, they see that the application runs on the Virtual Machine and from the perspective of the Application developers, they simply see that the Infrastructure team is providing a combination of three services namely Network, Compute, and Storage. This is the essence of the split.