Cloud Computing Industry Overview - SaaS vs IaaS vs PaaS

Let's quickly recap. When a company is looking for an enterprise application, its first decision is whether or not it will use an off-the-shelf solution. If it chooses off-the-shelf, it can rent the application via the cloud. This is SaaS. SaaS providers typically manage the rest of the stack as well. This is all part of the subscription. Any non-SaaS alternative – either buying the application or building it in-house, the DIY option – will require the company to secure infrastructure-level resources themselves. And the company has multiple options here as well. This is the second cloud or no-cloud decision. Let's take a look at their options. Before AWS and the era of the cloud, the primary option for companies to meet their infrastructure needs was to purchase, set up, and manage their own servers and data centers. This is now referred to as the on-premise or on-prem model. This is basically the no-cloud option. There are two cloud options as well. For one, companies can rent the infrastructure via the cloud from providers like AWS, Microsoft Azure, or Google Cloud. Renting the infrastructure means the company can avoid significant upfront capital expenditures for the hardware as well as the ongoing operational costs for maintenance, cooling, power, and IT personnel. This model is called infrastructure-as-a-service, IaaS, or IaaS. In this case, the company isn't getting any platform-level development tools. In practice, companies using on-prem models or IaaS might assemble various platform tools on top of their chosen infrastructure. However, the platform is not a key feature in these models. The second cloud option, on the other hand, is one that highly features the platform. In this case, the company can rent enhanced development tools, the platform, as well as the infrastructure. This is called platform-as-a-service, PaaS, or PaaS. The development tools made available via PaaS solutions can save the company time and effort down the line when building and managing its applications. For this reason, PaaS is most relevant when companies are doing at least some application building. Most of the major cloud service providers, like AWS, Microsoft, and Google Cloud Services, offer a range of both IaaS and PaaS solutions. A key driver in the IaaS versus PaaS decision is whether or not the application in question is new or existing. When moving existing applications to the cloud, companies might look for the least disruptive transition. And this often means IaaS, replacing on-prem infrastructure with a cloud-based equivalent but keeping their current software code largely intact. Any change to the platform will require changing the application's underlying code, and any benefits of PaaS may not be worth that effort. However, when the company is developing a new application on the cloud, it might consider other options. A new application is like a blank canvas. Developers can build it based on whatever cloud solution they choose. The trade-offs between IaaS and PaaS, in this case, come down to app development speed versus degree of control. PaaS solutions are designed to simplify and accelerate application development. This is the benefit of all those app development tools. For example, AWS offers a PaaS product called Elastic Beanstalk, which provides tools like automatic resource provisioning, a.k.a. automatic data storage optimization, or tools that help manage the launch of new version updates. On the other hand, PaaS solutions will reduce a company's degree of control over their code they're using and therefore relying on packages built and managed by the vendor. This in turn will make the company more reliant on the vendor. Vendor reliance, also called lock-in, can reduce a company's flexibility and weaken its cost-negotiating leverage. Just like any over-reliance on a supplier, it can be a strategic disadvantage. IaaS solutions, on the other hand, allow the company to maintain more control over the end applications. They can configure and fine-tune the code without relying on third-party tools. This can be useful when the company has specific requirements that aren't served by standardized PaaS packages. Naturally, this control also means they will be less reliant on the vendor. Of course, this control will mean extra work for the company during the application development process. IaaS solutions do not come with time-saving development tools. This second, cloud-or-no-cloud decision, on-prem versus IaaS or PaaS, is a big one for companies. At the enterprise level, solutions at the infrastructure level are costly and complicated. Imagine, for example, the impact of moving an enterprise application from on-premise infrastructure to the cloud via IaaS. This means migrating massive amounts of data, say patient health records or financial transaction information, and then reconfiguring a complex web of end-use cases, thousands of enterprise users, security requirements, and on and on. Making this type of transition often requires a large IT team and a big budget, possibly in the millions of dollars. When people say cloud computing, they typically refer to decisions related to the bottom half of this picture, options available at the infrastructure and platform layers. The rest of this primer, and any discussion of the cloud, will largely be focused on IaaS and PaaS accordingly.