Orange boxes here showing what you have to manage.
Yellow boxes here showing what cloud vendors manage.
On-premises: customer has to provision servers, storage, monitoring, installation and maintenance of services and applications.
Infrastructure as Service (IaaS): the customer can manage some of it, like the actual Hyper-V, the virtualization engine that your virtual machines are running on; the storage, the networking, the customer can also manage the OS. The customer can do whatever you want to with IaaS which makes it really nice for workloads that you have to customize a lot.
Platform as Service (PaaS): Cloud vendors are managing most of the stuff like
the operating system, the runtime, the middleware, the actual virtual machine itself or the host, and so in case of that, the customer just basically have to manage the application and data.
Software as a Service: In this case basically everything’s managed by the vendors. The customer doesn’t have to do anything; they don’t even have to bring applications way out, vendors already have it provisioned.
If we think of something – like a Software as a Service we have out there like Office365 or
something like that, even third party like sales force or something – those are SaaS
type vendors where you just go create an account, use the system; you don’t have to provision the application, it does it all for the customer.