Let's look a little more in depth at the various cloud service models.
Software as a Service is something we're all really very familiar with
where, for example, a consumer uses applications provided on and running on
the cloud service provider's cloud infrastructure.
The cloud service provider manages the application,
say, email or some type of streaming for some type of media.
And the consumer accesses the application through a thin client, say, a
browser or some type of application program interface.
The consumer may actually manage access for their users.
If I have an account to watch some type of streaming,
for example, shows on television,
I may be able to share that or have a family joint account for access.
In Software as a Service, we see here that the areas that are the
responsibility of then the Software as a Service cloud service provider
is then the actual presentation.
How would they then interface with the user? And the platform
used for that, the application program interfaces to access
things like their databases underneath the application. And of
course, they manage the data, metadata, and content that is available.
We can see then that this runs on top of a Platform as a Service, which, in
fact, also then runs on top of Infrastructure as a Service.
The division of responsibilities in Software as a Service
is as we looked at earlier in this course. The cloud
provider manages the application, patching it, and so on, such as mail.
They then, of course, also have total control and ownership of the
middleware, operating system, hardware, and even the facility.
The cloud consumer really has no control over where their data is stored or
processed, and very limited admin control say, for example, just things like
user access. When we look at Platform as a Service, this is where the consumer
can deploy customer created or acquired applications on the cloud service
provider's cloud infrastructure.
The cloud service provider provides library, services, tools, languages.
So say, for example,
I bought an application that I want to use, a finance application.
I could go to a cloud service provider and say I'd like to
run my application on your platform.
And the cloud service provider would then provide the
infrastructure for my application to run on the servers and
very often even databases and so on.
And the cloud service provider manages that underlying infrastructure
while the consumer has to manage their application, which would include
things like patching their application and so on.
If we look at this, now we see that the responsibility of the cloud
service provider is the element of infrastructure service, but on top of
that, the integration of middleware necessary for the application that the
consumer has purchased then to run on.
In this case, the cloud service provider has no control over the application.
It's being managed by the consumer.
They do the patching.
They still have admin control over middleware and total
control over the physical facility.
The cloud consumer has real control then over the application,
the installation, patching, and so on, access controls.
And they also then have to manage their interfaces between their program and the
underlying infrastructure. In Infrastructure as a Service,
the cloud service provider provides the building, the underlying infrastructure,
but the consumer manages operating systems, storage,
applications, and perhaps even some network components at times.
And in this case, of course, we said we could have a off‑site
private cloud be a very good example of this.
So the cloud service provider manages the facilities, hardware.
They manage the interface down to the hardware through some
type of abstraction, and they deal with,
of course, network connectivity.
And then there are the APIs, which become the interface between the
consumer and the cloud service providers areas.
In this case, the cloud service provider has total control over hardware.
They have admin control over the hypervisor,
but we can see here the cloud consumer has to be able
to interface with that as well.
And total control of the application middleware and guest operating system has
now passed from the cloud provider to the cloud consumer.