Welcome back to the Linux Foundation Certified IT Associate practice exam. In this module, we're going to think about Cloud computing, and specifically, were going to think about the competencies required in the Cloud computing section of the exam. When you're all done with this module, I want you to be able to describe the models of Cloud computing, discuss ways to improve performance and availability, list components of a serverless architecture, and list some costs associated with Cloud computing. There are three major types of Cloud providers. We have Software as a Service, Platform as a Service, and Infrastructure as a Service. Software as a Service essentially is replacing the idea of licensing software and delivering it or installing on your machines. Typically, this is a software that's delivered across your web browser and it's coming from the Cloud. Things like office software, like Google has Word processing, presentation software, spreadsheet, Microsoft has similar things. There's other third parties out there that offer similar things, messaging software, payroll software, accounting software, CRM software, ERP software. One of these things can now be delivered as Software as a Service. Platform as a Service is really geared towards developers. It's trying to get developers to market early, allowing those developers to focus on the development of a solution for the business functions and not all the common things we do when build software. Some examples of Platform as a Service offerings are Force.com, which is Salesforce's offering, or Google App Engine, which is Google's, and there're several other out there. Infrastructure as a Service. This category includes virtualization software that allows an operating system to be run in the Cloud. Essentially, our goal was to free the user from the purchase of hardware and allow the hardware upgrades easily. Some examples of Infrastructure as a Service are Amazon EC2, Rackspace, Digital Ocean, Microsoft Azure. All of these allow you to essentially spin up these virtual versions of the operating system without hardware. Now, you're still responsible for what goes into that hardware. You still need the IT staff typically, but you don't need the closet down the hallway. You don't need to cool that closet. You don't have to worry about fire, all those things. We also have a relatively new concept of serverless computing. This is a Cloud computing execution model in which the provider is allocating machine resources on demand. It's taking care of the servers on behalf of their customers. You do not hold resources in volatile memory. Computing is rather done in short bursts with the results persisted to storage. One specific implementation of serverless computing is Function as a Service. This is the most widely used serverless solution. It allows users to execute code in stateless containers that are executed according to some predefined events, and when those events are happening, the resources are spun up. Another concept we're going to think about here is load balancing. Load balancing essentially allows us to officially distribute incoming network traffic across a group of backend servers. This is also known as a server farm or server pool. I have a little diagram here where we've got some web services that are redundant sitting behind some dispatcher of work. These web services may share a database behind them. But essentially, I can add servers in this layer to handle larger loads of traffic. Lastly, in this module, we want to think of cost of moving to the Cloud. We have direct cost. These are things like the cost of labor for maintenance on your servers, your database and other technology. They can be cost to maintain the facilities that house IT hardware such as real estate staffing and other facilities related costs. Cost of connectivity to the Internet. Any other cost that can be attributed to the care of your IT, but also your purchases, what you paid for the software, the hardware along with those operational costs. You also have cost of new Cloud Infrastructure. Purchasing of servers or storage or different services. Then a big one here is the cost of migration. This is moving data, integration and testing, and consulting. You want to think about all of these costs when you're thinking about, am I saving money? am I paying more? Often, it doesn't save money, but it gives you more uptime, less risk, so you don't have a single person you're relying on within your organization. You've got a service provider providing that through the Cloud service provider. If you lost that one person, it would not be as big of a risk. A little review here. Infrastructure as a Service does not eliminate an organization's need to manage the operating system. Serverless is a model where the Cloud provider allocates resources when needed. Lastly, when estimating cost of moving to the Cloud, you need to consider the migration cost along with the other costs. See you in the next session.