The first thing you need to know about this section of the exam is what exactly cloud computing is, why we should use it, and the different types there are. So, cloud computing is a "remote virtual pool of on demand shared resources that can be rapidly deployed." But what does that mean?

Well, essentially, whatever resource you're using, it can be scaled up or down depending upon your needs. One of the main benefits to cloud computing is that it can drastically reduce costs to an organization. Since cloud services are all managed by an external vendor, the organization no longer needs to spend money on hardware. Since you no longer need to manage the hardware, the energy cost associated with it and the need for IT staffing is lessened and is no longer your responsibility. And perhaps the most apparent would be the maintenance and upfront costs that would be unnecessary since you can simply pay for the resources you need from vendors. 

But alongside the cost saving benefit, there are many more worth mentioning. Reliability and scalability are also some massive upsides to cloud services. If you have 50 users, each of which needs a laptop with some application installed, you would need to provide and maintain 50 laptops and applications. But what happens if you hire another employee? 10 more? 50 more? Well, then you need to go out and purchase and maintain all of that hardware for those users. If you were using a cloud service model like Microsoft 365 rather than having to purchase, update, and maintain the hardware, you would simply need to go purchase however many more licenses you need and that's that. Being able to scale up quickly is a huge benefit of using cloud services and not only saves large amounts of money but also time. 

Okay, so now we have an understanding of what cloud computing is and some benefits it can provide, but what types of cloud computing is available? Well, technically there are three: Public, Private, and Hybrid. Each of these provide some variation of the benefits I mentioned earlier. A Public cloud is where a third party owns and maintains the resources which can then be rented out by the public. The one thing to remember about public clouds is that you could be sharing resources with other organizations. Microsoft Azure is an example of a Public cloud. A Private cloud is defined by its name, private. It can be maintained by a third party or located on site, but the main differentiator is that all of the resources are solely dedicated to a single organization. 

While it provides more control over the environment, it also comes with an increased cost over public clouds and is generally used by organizations like financial institutions or government agencies. A Hybrid cloud is a combination between public and private cloud services. Maintaining a private cloud while gaining the benefits of utilizing a public cloud as needed is the defining characteristic of a hybrid model. Now that we understand the cloud model types, it's time to get into the cloud delivery models. This is simply how the services are delivered and are known as IaaS, PaaS, or SaaS. IaaS is short for Infrastructure as a Service. PaaS is short for Platform as a Service, and SaaS is short for Software as a Service. 

IaaS allows the most customizability with your environment where you pretty much control everything except for the underlying hardware. An example of an IaaS solution is something like Amazon Web Services or Microsoft Azure. PaaS is the middle ground between SaaS and IaaS. It allows you more control over your environment. However, the service provider still manages things like the operating systems and servers. An example of a PaaS service  is something like the Google App Engine. And finally, SaaS, which is arguably the most utilized in the world today. This is where the service provider maintains pretty much everything from the servers you're accessing straight down to the applications you're utilizing. 

SaaS allows you to simply access applications over the Internet without having to worry about installations or maintenance. A good example of a SaaS provider is Microsoft 365. You simply pay for your subscription to the service and you get access to everything from an email server to the entire office suite and more all accessible via a web browser. If you're still confused, take a look at this visual. As you can see, each delivery model varies on what you manage versus what the provider manages. To make it easier to remember, a SaaS provider pretty much manages everything for you, and the IaaS provider manages the least. And the PaaS provider falls somewhere between there as you can see on the graphic. For more clarification on this, you can check out the cloud service model course earlier on in this learning path.