Cloud service models

In the previous sections, we discussed where and how our cloud services can be deployed. In this section, we will talk about who is responsible for which level of maintenance of service and how the most common service levels – Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS), and Software-as-a-Service (SaaS) – differ. Furthermore, we will discuss the modalities that customers can expect when choosing a certain service model. We will also discuss some service models that are not part of the NIST specification but are also often used in current environments and, therefore, might have relevance for continuous delivery.

In traditional infrastructures, system and network administrators often mounted servers in racks, installed the operating system software on them, and ensured that there was enough storage and a proper network connection to provide a good service where applications could be deployed. These are the services we find in...