What are the different types of cloud?

Natasha Ong
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4 min read

In a nutshell:

Cloud models are about where your cloud  lives and who can use it.  

Public Cloud is like a digital playground for everyone, where cloud services by third-party providers (like Azure) are available to all.
Private Cloud is your secret cloud garden with high control and security, used exclusively by a single entity.
Hybrid Cloud combines the best of both worlds, blending public and private clouds for flexibility and added security.

Cloud service types determine the level of control and management the customer gets.

Infrastructure as a Service (IaaS) is like renting cloud-based hardware while you have control over software and configurations.
Platform as a Service (PaaS) is your shortcut to app development, where the cloud provider manages infrastructure, OS, and more.
Software as a Service (SaaS) is like renting complete applications; no technical expertise needed, just enjoy the software.

So we've learnt that cloud is different from running your computing on-premise, but did you know there are different models and service types with the cloud too?

Cloud models and service types exist because different people have different needs. Some want more control, while others want more convenience, so there are different types of clouds and services to match those needs.

What are cloud models?

There are three primary cloud models: private, public, and hybrid.

Public Cloud

Public clouds are built, operated, and maintained by third-party providers (like Microsoft offering Azure), renting out cloud services to the public over the public internet. They are known for their wide availability - anyone that wants to use public cloud services, can use it.

Example Azure products and services:

  • Azure Portal
  • Azure Functions

Private Cloud

The private cloud is a cloud that's used by a single entity. Services can be delivered over the internet, but they're typically delivered over private network or connections! This means the big differences between the public and private clouds are the level of control, security and customisation.

The private cloud is a tricky one, because when someone says a company is using the private cloud, it can mean one of two things:

  1. Traditional private cloud: In a traditional private cloud, organisations do invest in and manage their hardware and infrastructure. In some cases, they also handle the associated hardware and maintenance costs. BUT these data centres may not be located in the organisation's premises - they might rent or own dedicated data centre space with a cloud provider (i.e. Azure might rent out entire parts of their data centre so the servers are fully dedicated to one single company). That makes it different from an on-premise setup, where data centres are always located within the company's physical facilities.
  1. Virtual private cloud: Some organisations choose to create a private cloud using services from a public cloud provider. They don't invest in physical hardware or the infrastructure (unlike the traditional private cloud), but benefit from the isolation and control that a private cloud offers. You'll learn more about how this works when we talk about the Azure Virtual Network!

Example Azure products and services:

  • Azure Virtual Network
  • Azure ExpressRoute, which provide dedicated private  connections to Azure

Hybrid Cloud

Hybrid clouds integrate both public and private cloud environments, allowing them to work together. This setup can handle temporary surges in demand by leveraging public cloud resources. It also gives us flexibility in choosing which services to keep in the public cloud and which to put in the private cloud, adding an extra layer of security.

Here's a quick overview of key differences between cloud models:

Example Azure products and services:

  • Azure Arc extends Azure services and management to any infrastructure
  • Azure ExpressRoute privately connects on-premise networks to the cloud

Bonus: Multi-cloud

In a multi-cloud scenario, organisations use multiple public cloud providers. This approach might involve selecting different features from different providers or migrating from one provider to another. In a multi-cloud environment, managing resources and security across two or more cloud providers becomes crucial.

What are cloud service types?

Infrastructure as a Service (IaaS)

IaaS is a cloud service type where the cloud provider handles hardware maintenance and network connectivity, while you take charge of everything else, including operating system installation, network and database and storage configuration, and more. This makes IaaS the most flexible category out of the three, and gives you the maximum amount of control too.

Common scenarios include:

  • Lift-and-shift migration: Companies usually start their journey into the cloud by using IaaS services to replicating their on-premises setups in the cloud. They're running the same things, but everything is running on IaaS infrastructure now.

For example:

  • Azure Virtual Machines (VMs): Azure VMs provide virtualised computing resources where you can install and manage your operating systems, applications, and configurations. This IaaS offering offers complete control over your virtualised infrastructure.
  • Azure Blob Storage: As part of Azure's storage services, Azure Blob Storage allows you to store unstructured data, such as documents and media, similar to how you would manage your own on-premises storage hardware.

Platform as a Service (PaaS)

PaaS falls between renting data centre space (IaaS) and using a fully deployed solution (SaaS). Here, the cloud provider manages the infrastructure, operating systems, middleware, and more, so you can focus on developing applications. No need to worry about the licensing* or patching** for operating systems (OS) and databases (phew)!

*What is licensing? Licensing is like a permission slip you need to use certain software. It's an agreement between you and the software provider that outlines the terms and conditions for its use.  For example, when you subscribe to a SaaS app like Netflix, you're essentially obtaining a license to use Netflix on a recurring basis, usually under specific terms and conditions. Licensing for databases and OS is common in the business world. For example, a company might purchase a license from Microsoft to use their Windows Server OS on their server computers. Similarly, they might acquire a license from a database provider (a famous one is called Oracle) to use their database software for managing and storing business data, agreeing to specific terms and fees set by these software providers.
**What is patching? Patching is like fixing small holes or issues in the software, just like sewing up a hole in your clothes. It's important because it helps keep the software secure and running smoothly by addressing any problems that might pop up over time. Think of it as regular maintenance to ensure your digital tools work well and stay safe.

Common scenarios include:

  • Development framework: Developers use PaaS to build cloud-based applications with built-in components. Cloud features like scalability, high-availability, and multi-tenant capability* are included, reducing the coding work for developers.
  • Analytics or business intelligence: PaaS services let companies mine their data, find insights and patterns and make better decisions.
*What is multi-tenant capability? Multi-tenant capability in the context of PaaS means that the platform allows multiple users (i.e. the 'tenants') to share the same underlying infrastructure and resources while keeping their data and applications separate and secure. This lets different people run their software on the same platform without interfering with each other. It's a huge plus for efficiency and cost-effectiveness because it optimises resource utilisation, making it more practical for developers and businesses to build and run applications in a public cloud environment (e.g. Azure, AWS)

For example:

  • Azure App Service: Azure App Service is a Platform as a Service (PaaS) offering that simplifies building, hosting, and scaling web applications. Developers can focus on writing code, while Azure handles infrastructure provisioning, patching, and scaling, making it an ideal choice for application development and deployment.
  • Azure SQL Database: Azure SQL Database is a managed database service that operates within the PaaS model. It provides a platform for running SQL databases without the need for manual management of the underlying infrastructure. Developers and businesses can concentrate on database design, queries, and applications, leaving Azure to manage the database service.

Software as a Service (SaaS)

SaaS is the most complete cloud service, where you rent fully developed applications like email, financial software, and messaging tools. It's easy to set up as you don't need extensive technical expertise, but it's also the least flexible.

Common scenarios include:

  • Email and messaging: Using cloud-based services for communication.
  • Business productivity applications: Tools for better work efficiency.
  • Finance and expense tracking: Managing financial data with ease.

For example:

  • Microsoft 365: Microsoft 365 is a prime example of Software as a Service (SaaS). It offers a suite of productivity applications like Word, Excel, and Outlook, directly accessible from the cloud. Users can access these applications without the need for installation or hardware management.

Here is a quick overview of the key differences between IaaS, PaaS and SaaS:

And that's a wrap!

Do you find the different cloud models and cloud service types a little similar?

It can be quite difficult to tell the difference between them. For example, what's the difference between a private cloud and IaaS? It sounds like they're both all about letting the cloud provider handle the hardware, while you handle everything else.

To put it simply, service types are about how you use the cloud, and cloud models are about where your cloud stuff lives and who gets to play with it. You can mix and match these to create the perfect cloud setup for your needs.

Cloud service types (IaaS, PaaS, SaaS) are like different flavours of how you use the cloud. They determine what you're responsible for and what the cloud provider takes care of.

  • With IaaS, you're in charge of a lot, like setting up the computer's operating system and software.
  • PaaS makes things easier because the cloud provider handles more of the technical stuff, like the operating system and tools for making apps.
  • SaaS is the easiest; you just use a complete app without worrying about anything technical.

On the other hand, cloud deployment models (private, public, hybrid) are about where your cloud stuff lives and who can use it.

  • Private cloud is like having your own secret cloud that only your company uses.
  • Public cloud is like a big shared playground in the internet where anyone can use the swings and slides.
  • Hybrid cloud is a mix of both, so some of your stuff is on your private playground, and some are on the shared one.

An extra for the curious

So if you're wondering how different cloud service types and different cloud models might work together, here are a few example use cases: