Welcome to Linux Cloud and DevOps. This is the 4th course in the Linux Foundation Specialization. Okay, so in this module, I want to think about cloud computing models, and what I mean by this is different ways that we use the cloud for computational needs. So by the time we're done here, I want you to be able to describe three different models, software-as-a-service, platform-as-a-service, and infrastructure-as-a-service, and the different use cases that go along with those models. All right, so let's start out thinking about software-as-a-service. All right, so there are three types of cloud providers, software-as-a-service, platform-as-a-service, and infrastructure-as-a-service. Software-as-a-service is a software licensing and delivery model in which software is licensed on a subscription basis and is hosted in the cloud. So let's think about that a little bit and decompose that a little bit. So we've talked a lot over these courses about open source software, but you can use Linux in the cloud and have software that's licensed in the traditional models. But people learned years ago you can make more money selling, like Kodak did, film processing than the cameras, right? So Kodak made most of its money not on cameras but on processing film. And the cloud software-as-a-service is essentially the same idea where a software vendor can make a subscription charge where they're charging their customers every month while they use the software instead of charging them every time there's a major upgrade. That includes hosting, which means that the customer is using the software as a service providers' servers in the cloud. Okay, these apps are typically accessed by users using a thin client. Now, often a thin client is a web browser, but a thin client could be like a Citrix or remote desktop if you're using software-as-a-service in a traditionally old, what I'd call a fat client, where you have a Windows natively developed application or Linux GUI distributed that way. But typically, these are these are delivered over a web browser, and so there's many different business applications that use this model. So office software, we'll look at some examples, but typically Office 365 and Google G Suite come to mind, right? So what we mean by office software is things like word processing and spreadsheets and presentation software. Messaging software is things like email and calendaring. Payroll processing software, this was a huge leap for a lot of accounting departments because they had to process payroll and send in the data on a biweekly or weekly basis. Well, now it's all up in the cloud, so they're using the software-as-a-service to enter the the payroll information and the vendor that's going to cut the checks already has all that data. Accounting software has moved there where instead of installing software locally, you just use your web browser to get to the accounting software. Collaboration software, we have a couple of big ones with CRM, customer relationship management and ERP, which is enterprise resource planning. In higher education, we use learning management systems, and in IT support, we often use service desk management or content management systems. All right, we also have this idea of outsourced IT. So when you're using software-as-a-service, you no longer need IT people to run around from machine to machine for software upgrades. Now, I may be dating myself. You may be too young to have seen this in an office, but it used to be in the old days you'd have downtime when you did a software update. So let's just think about this from the perspective of you have some main business application that you run your business on and you have 20, 30, 100 users using that application. You would need to upgrade every workstation simultaneously before any user can log in. And typically, people do this at night time. They would have IT people running from machine to machine, installing the update from a CD, installing license keys, rght? And every machine had to be updated. A few of them probably had problems. It was a nightmare. This goes away with software-as-a-service, right? There's no more DVDs, no more license keys to manage. This is typically delivered in a web browser. Okay, so some examples SaaS providers, Microsoft Office 365, this is a big one, right? Microsoft is trying to move all of their desktop software for Word, spreadsheet, PowerPoint to the cloud. Google came in and google started as a software-as-a-service provider. So the G Suite is typically free, but they have an enterprise model for corporations to share data across users. And Zoho is a big provider of software-as-a-service software. Okay, so let's drill into these a little bit. So for Microsoft Office 365, you have Outlook, which is your messaging and calendaring. You have Word for word processing, you have Excel for spreadsheets, you have PowerPoint for presentation software, you have Teams for video sharing. That became very popular during COVID, and many, many more applications. If you have an Office 365 license, you'll often see new software show up there as they're trying it out. And really, this is Microsoft's office software strategy for the future, is software-as-a-service. Google, Google started out this way with very similar products. So you had Gmail for messaging and calendaring, Google Sheets for spreadsheets, Google Meetings for video sharing, Google Docs or word processing, Google Slides for presentations software, plus more and more things are showing up there. Zoho is a software provider, you may see them in the airports. They advertise a lot, they have lots and lots of software-as-a-service. So mail, so they have their own email and calendaring, they have their own word processing, they have their own spreadsheet, they have their own presentation software, they have their own meeting software. So just like Microsoft and Google, Zoho is in there competing. But they have accounting software, they have a CRM product, and they have many, many more products. I encourage you to go up to Zoho and check it out just to get a good framework of the kinds of applications that can be delivered across software-as-a-service today. All right, so why are we talking about software-as-a-service and Linux? All right, so we talked about why a customer may want software-as-a-service, but what about service providers? We've already explored Linux has no licensing fees to spin up additional servers. You can just add servers. You don't have to go pay Microsoft or another vendor for licensing fees for Linux. And that low cost of scalability and large feature set makes Linux attractive for the software-as-a-service service providers. All right, a little bit of review here. Software-as-a-service is when our apps are hosted for us. Users require less IT support for software-as-a-service. And Linux is a great solution for software-as-a-service service providers. All right, see in the next lesson
