There are many different types of services available in the cloud. These services can typically be grouped into a few different models. I'm now going to talk about the three most common, infrastructure as a service, platform as a service and software as a service. You've probably used many examples of software as a service, or SaaS, without even realizing it. SaaS offerings are ready to use applications. There's nothing to install or maintain. Users can simply access the application over the internet. Probably one of the most well-known examples of this would be Google Gmail. Any user can sign in and access their email over the internet. You don't have to install anything. As long as you can bring up a browser, you're good to go.

SaaS offerings require little to no setup, but usually offer the least amount of customization. Platform as a service offers a greater level of control, but it requires more setup. Essentially, you're given access to a certain environment and you can build or run whatever you want on it. The underlying architecture, the hardware operating system, and maybe even things like libraries, those are all managed by the cloud vendor. Basically this gives developers a simple platform to deploy and run code on. They can concentrate on writing software and they don't have to waste a lot of time maintaining, upgrading and patching servers.

The highest level of customization offered is on infrastructure as a service. Now these services give you the option of architecting your own virtual data center. You can start out by configuring a virtual network with routers, firewalls and private IP address ranges. Then you can configure different virtual machine instances. You pick the operating system at the libraries, install any applications. It feels a lot closer to your traditional on premises data center. Now, this service does offer the highest level of customization and control, however, the underlying hardware is still managed by the vendor. So you're not going to have complete control and there are going to be some limits on what you can and cannot change. Now, these aren't the only service models available. You have other ones like disaster recovery as a service communications as a service and monitoring as a service. For the purposes of this course, we're not going to go that deep. However, you should be aware that more and more of these services are popping up all over the industry.