IaaS, PaaS, SaaS: the differences between cloud models & examples

What are the IaaS, PaaS and SaaS service models? What are they used for and what is the difference between them? This article will help you find the answers to these questions.

What is the cloud?

Cloud computing is a way of providing remote access to computing resources through the internet. The cloud is built using multiple physical servers that work in a single system. These servers are segmented into virtual machines (VMs). Just like a physical server, a VM has a CPU, RAM, storage etc. However, the configuration of each VM is not limited by the physical hardware on one machine. For example, you can increase the amount of RAM or turn off CPU cores at any given moment. This is possible because virtual machines use the resources of multiple physical servers at the same time.

Clouds are used for a variety of corporate tasks, such as deploying e-commerce projects, data bases, ERPs, mail servers etc. In other words, the cloud is a virtual IT infrastructure which can be used to deploy any corporate systems and applications.

Why do companies choose cloud solutions? Here’s a couple of reasons:

• access through the internet, no matter the time or the user’s location;
• no need to hire administrators, update software or hardware – this is the provider’s responsibility;
• instant scaling through upgrading virtual resources;
• various access rights levels for users;
• comprehensive services and support.

IaaS, PaaS, SaaS and XaaS are cloud service models; the difference between them lies in the levels of the tasks they solve. The IaaS model provides the client with the computing resources of the cloud; this infrastructure is used to deploy software solutions. PaaS is a model which includes cloud resources and pre-installed tools for various tasks. SaaS users get a full solution, which only needs to be applied; it’s likely that you’ve encountered SaaS services in your everyday life. All of these models can be broadly defined as XaaS, meaning «Anything-as-a-Service».

What is IaaS? (Infrastructure-as-a-Service)

IaaS (Infrastructure-as-a-Service) is a cloud service model which includes all the basics: server infrastructure, network equipment, storage, etc. Instead of maintaining your own IT infrastructure, you rent a cloud while the provider supports it.

The main benefits of IaaS:

• less spending, as all maintenance costs are the provider’s responsibility;
• the data is located in the provider’s data center, where it’s protected by physical and digital security systems;
• simple scaling that follows the company’s growth.

IaaS is the resource base for the company’s services. IaaS providers offer less services than in the other models. Depending on the company’s needs, this could be a benefit. If you have your own strategy when it comes to developing IT solutions, this model will give you the greatest freedom to implement it. IaaS is used to deploy individual apps, as well as the company’s entire stack of IT instruments: ERP systems, terminal servers, remote offices, data bases etc.

IaaS administration and monitoring is carried out through a virtual interface. It allows you to adjust the configuration, add software and additional services offered by the provider.

If a project requires additional resources, all you have to do is add them in the dashboard. For example, you can expand the storage or choose another CPU & RAM combination. If the company is not using all cloud resources, it is just as simple to turn off the ones you don’t need and pay less. All maintenance and support costs are the responsibility of the provider. The company does not need to set up its own data center, pay for electricity or cooling systems etc. This way, IaaS rental allows clients to spend less money and time on IT.

Learn more about the advantages of cloud solutions for corporate clients in various industries in «Do businesses need the cloud?»

The choice of an IaaS solution must be approached from an informed position. When choosing a cloud for your business, take these factors into account:

• Does the provider use redundant components for fault-tolerance?
• How is data protection organized?
• Is the provider’s data center Tier III or higher?
• What guarantees are included in the provider’s SLA?
• Is the tech support service available 24/7?
• What additional XaaS services does the provider offer?

Learn more about the factors of choosing an IaaS cloud; get acquainted with a comparison of SIM-Cloud with Amazon Web Services

XaaS («Anything-as-a-Service») refers to various cloud services. The «X» in the abbreviation is a variable, meaning that this term can refer to any service. In the context of cloud infrastructure, XaaS often refers to additional services meant for use with IaaS. BaaS («Backup-as-a-Service»), automatic reserve copying in the cloud, is a common example of XaaS. The abbreviations used for XaaS services may have different meaning based on the providers and the context. «MaaS» can stand for both «Mobility-as-a-Service» and «Malware-as-a-Service.

What is PaaS? (Platform-as-a-Service)?

PaaS (Platform-as-a-Service) is a service model which provides the client with an preconfigured environment for developing and deploying applications. PaaS examples include email servers, data base management systems, web-servres, development and testing platforms, backup servers etc.

The benefits of PaaS solutions:

• PaaS providers are responsible for any updates and fixes for the software;
• the client doesn’t need to invest in hardware or software – the provider offers the full platform for rent;
• flexibility during deployment: the infrastructure is fully controlled by the provider.

PaaS is similar to IaaS in its purpose; however, PaaS clients cannot scale the infrastructure. This means that the user cannot turn off surplus resources or add more. The difference between IaaS and PaaS lies in the fact that Platform-as-a-Service provides you with a computing platform and stack of solutions, but you cannot adjust the configuration. Standardized development toolkits are a good reason to pick PaaS. This can significantly improve the efficiency of a team working on the same project.

PaaS (Platform-as-a-Service) examples: Google App Engine, VMWare Cloud Foundry, IBM Bluemix и др.

PaaS gives the user less freedom than IaaS, but rids you of the need to solve issues that have already been solved by the provider’s package of services. The choice between IaaS and PaaS is a question of whether this package corresponds to your business needs.

What is SaaS? (Software-as-a-Service)?

SaaS (Software-as-a-Service) is a model that provides an application deployed on the provider’s infrastructure. SaaS is a common model that you’ve likely encountered in your everyday life. Typical SaaS clients include end-users of email services, streaming services, small-scale cloud storage, messaging apps etc. Social networks are provided using the SaaS model.

Corporate SaaS clients use apps for video conferencing, ERP and CRM systems, project and time management apps, email services etc. You’ve likely heard of these SaaS (Software-as-a-Service) examples before: Gmail, Jira, WordPress, Citrix etc.

SaaS is a great choice if the provider’s services solve your business tasks; all you have to do is apply a ready-made solution. However, if you need a more specialized approach which calls for developing your own instruments, one of the previously mentioned models will be better-suited to your needs.

How do I choose a cloud service model?

The choice of a cloud service model isn’t a difficult one if you have a full understanding of your company’s needs and capabilities.

IaaS is a solution for deploying apps and systems from scratch, which is why it is most often used by corporate clients. Startups and small to medium businesses often choose IaaS because of its relatively low price and quick scaling that can match the company’s growth.

PaaS gives you the resources of the cloud and a set of development tools. The preconfigured platform is a convenient solution if the company needs to solve a certain task for the project, and the provider has all the necessary instruments.

Finally, SaaS is a ready-made product developed, deployed and supported by the provider. These solutions are used by both individual clients and companies. The SaaS model includes messaging apps, CRM systems and other software.

All of these models are based on the cloud; the differences between them lie in the software. The choice of a service model is a question of whether this software solves the company’s problems. If your task has already been solved by the provider’s package of services, choose SaaS. If the provider doesn’t have a ready-for-use solution, but has all the necessary tools to develop it, PaaS rental is a good choice. If the company needs raw computing power to deploy its own solutions, IaaS is the perfect model.

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