Cloud has been on everyone’s mouth. Whether you are already using a cloud computing model or looking to migrate, choosing the right cloud solution — PaaS vs IaaS vs SaaS — can be a hassle. 

Nonetheless, making the right decision early on is crucial for the success of your business and it can save you a lot of trouble and costs in the long run. Contrary to traditional IT and on-prem solutions, PaaS, IaaS, and SaaS offer different levels of autonomy and control and suit different business needs.

Let’s take a look at each one of them.

IaaS: Infrastructure as a Service

As a cloud model, IaaS uses virtualization to deliver cloud infrastructure including servers, network, storage, and operating systems (OS). IaaS is often considered the most flexible cloud computing model as it gives users complete control over all infrastructure aspects. This is made possible mostly with the use of dashboards and APIs. 

Contrary to the other two models, IaaS users are required to manage many infrastructure aspects—applications, data, runtimes, middleware, and OS—while the provider manages servers, storage, networking, as well as visualization layers. 

IaaS characteristics

The main characteristics of IaaS include:

• Flexibility: gives you more options to deal with future, yet unknown challenges and decisions. 
• Highly scalable services: mitigates resource utilization and stability issues with clean abstraction and tooling (CLI, SDK, API, etc.).
• Consumption-dependent costs: IaaS is a pay-as-you-go service and shifts the budget from building an on-premise infrastructure to innovation and business operations.
• User maintains control of the infrastructure: identity and access management (IAM) and security remain at the hands of the end-user, not the vendor.
• Resources are available as a service: IaaS provides basic blocks of computing power, for example, CPU, memory, and storage—all of them living in a geographic perimeter.

IaaS advantages

IaaS is a cloud model that has a lot to offer. Some of its advantages are:

• No need to invest in expensive infrastructure—are resources provided by the vendor.
• It’s highly scalable.
• It’s a pay-as-you-go service that makes it easy for the end-user to purchase resources, scale, or downsize depending on business needs.

IaaS disadvantages

IaaS brings a nice set of pros but there are definitely some cons that need to be addressed.

• Security. While it surely is an advantage for the user to be able to maintain control over the infrastructure, there are a number of security threats that can still creep in from the host or other virtual machines (VM). The fact that multiple clients are using one piece of hardware also raises some security concerns. Users rely on the vendor to make sure all VMs are properly isolated.
• Unpredictable costs. Sure, the highly scalable nature of IaaS is most certainly a desirable feature but it can also cause problems if instances are not monitored properly and shut down when not needed. If your organization does not have a cloud engineer or FinOps engineer, these mistakes are more likely to happen.
• Training. Managing cloud infrastructure is no walk in the park. One common mistake to make is thinking that IaaS is the same thing as managing servers on-prem. It’s not the same job, and the skills required are not the same. You need to keep in mind that your staff may need additional training in order to effectively manage the infrastructure. Otherwise, there is the risk of making important mistakes when designing or operating cloud infrastructure: downtime, performance issues, crazy bills, frustration, etc.

PaaS: Platform as a Service

Being the middle child of autonomy and control, PaaS is a cloud computing model that provides developers with a platform to develop, deploy, and run applications. Its main goal is rapid development and that’s the reason why it aims to eliminate the costs and complexity that come with configuring, deploying, and managing the required infrastructure. 

PaaS characteristics

All PaaS technologies are following the shared responsibility model, which is the only common characteristic between PaaS and other models. A PaaS platform is responsible for:

• providing an infrastructure—servers, network, storage
• bootstrapping and deploying servers—install and configure OS, install the desired runtime, as well as install security patches and keep them up to date.
• providing middleware services—database, messaging service, cache storage, etc. The types of middleware provided always depend on the choice of PaaS and its implementation.

PaaS advantages

PaaS has many advantages but to sum it up: 

• it offers the right level of abstraction for developers
• it is a pay-as-you-go service
• it is built on shared good practices

PaaS disadvantages

There are plenty of narratives picturing this model as a technology that has reached its peak of effectiveness while others, rightfully so, point to a few disadvantages that come with using this model.

• One size does not fit all. With an ever-expanding IT landscape, a PaaS solution is bound to select the most relevant stack of components and build a consistent offer with their best level of integration, security, and support. That means leaving a whole range of projects out of its scope.
• Vendor lock-in. You must be very careful when auditing and choosing a vendor. Whether the vendor you chose runs out of business or no longer serves the needs of your organization, a migration can impose significant costs and in-house engineering work.
• Financial viability. Management can not always have full visibility over the resources their engineers are using. 

SaaS: Software as a service

It is safe to say that SaaS has been the most popular cloud computing model so far. PaaS delivers applications over the internet and this is the main driver behind its success. The end-user does not need to download the app, instead, they can run the software directly on their browser which makes SaaS highly scalable and, of course, easy to use and manage. 

SaaS characteristics

The main characteristics that define SaaS include:

• Users are not responsible for managing and maintaining hardware and software.
• Offers access over the internet, mostly through web browsers.
• It is hosted on remote servers.
• It is managed by third-party vendors. 

SaaS advantages

The main characteristics of SaaS are also its advantages:

• in most cases, software accessible on any device over the internet
• cost and time-effective since you don’t have to worry about installing, managing, or updating software

SaaS disadvantages

If SaaS looks too good to be true, well, you’re right—at least in some cases. Here are some cons you should keep in mind:

• No control over the infrastructure. While PaaS and IaaS offer a certain level of control over the cloud-based infrastructure they run on, SaaS does not. This can cause massive outages—if the SaaS platform is out, so is your application. 
• Compatibility and integrations. A SaaS solution may not be compatible with other tools you’re already using, so integrations can cause major issues. 
• Vendor lock-in. Similar to PaaS solutions, choosing the wrong vendor can become very costly. 
• Little to no customization. Contrary to PaaS and IaaS, SaaS solutions offer very limited customization options on functionality, performance, integrations, etc. 
• Security. In addition to having no control over the infrastructure, SaaS users don’t have any control over the security measures put in place by the vendor. In the case of an attack on the vendor and a potential data leak, your organization’s data may also be exposed. 

PaaS vs IaaS vs SaaS: which one to choose? 

The answer to the question PaaS vs IaaS vs SaaS is not a simple one. All three cloud computing models have advantages to offer and disadvantages to consider. But they also offer different levels of flexibility, scalability, and control to fit any business needs.

IaaS

• IaaS is the most versatile model and it’s a great option for startups and SMEs. 
• Gives a high level of control over the infrastructure, a feature that can be highly appreciated and utilized by big enterprises. 
• Its level of customization makes this model an excellent choice for creating highly customizable apps.
• Its scalability also brings great advantages for organizations experiencing hyper-growth. 

PaaS

• Definitely, the best option when you need to develop and deploy applications fast while having multiple developers working on the same project. 
• If you are on a tight budget, PaaS solutions can be very cost-effective compared to hiring an entire DevOps team. 
• Sitting between IaaS and SaaS, PaaS offers a satisfying level of customization, making it a great choice for those who want to customize certain aspects of their applications but not go in too deep. 

SaaS

• The need for quick wins is the number one scenario where SaaS solutions would be most beneficial—quick launch of apps without having to worry about server or software issues. 

Whatever your needs are, surely there is a cloud computing model that suits your business. Choose wisely and have fun!