You now know that the application areas of Cloud Computing are almost unlimited. Now all that remains is to clarify what different types of clouds there are.
The US-based authority NIST (abbreviation stands for National Institute of Standards and Technology) distinguishes four different basic types of clouds:
- Public Cloud
- Private Cloud
- Community Cloud
- Hybrid Cloud
This categorisation is about how the Cloud Computing offering is delivered. Let’s go through each type together.
Public Cloud: In the public cloud, the cloud resources are available to the general public. In a sense, it is there for everyone. But the individual users of the public cloud do not know who else is accessing the cloud resources. The cloud is shared with everyone who wants to use it.
In this “classic form” of the cloud, the cloud infrastructure is operated and maintained by cloud providers. This happens off-site. This means that the infrastructure is not located at the individual people using the cloud, but is distributed to external data centres and servers. The providers of public clouds are usually large companies.
We have already seen examples of public clouds above: Amazon, Google and Microsoft operate public clouds.
All cloud services that are available to the general public are referred to the term Public Cloud Computing.
Amazon Web Services (AWS) as pioneer among public clouds and IaaS providers
Amazon Web Services (AWS), a subsidiary of the shipping giant Amazon, was one of the pioneers in Cloud Computing.
Early on, Amazon had decided to rent out its huge server capacities to other companies at a profit. The economic figures show that this was a very good idea. Since its official founding in 2006, Amazon Web Services has developed into one of the company’s top-selling divisions.
As of 2019, AWS is the world’s leading cloud provider of Infrastructure as a Service (IaaS) and has many large companies as customers.
Did you know, for example, that in 2019 the streaming service Netflix, the booking platform Airbnb or even the US space agency NASA used storage capacities at Amazon Web Services?
Private Cloud: A private cloud is now an exclusive cloud. The cloud infrastructure is only used by a single customer. A network of servers is reserved or even built specifically for a company. No one else has access to this form of cloud.
Private clouds can either be located locally on company premises or can be rented from specific cloud providers. They can therefore be located on-site or off-site.
So if a cloud is reserved for corporate use only, it is a private cloud. This means that Amazon’s server network was a private cloud before the founding of Amazon Web Services (AWS) – only Amazon itself used its IT resources.
Cloud Type = Deployment Type
The different types of clouds are not about how the cloud is used, but by whom. In other words, it’s about how the IT offering is delivered and how many companies or individuals have access to the cloud!
It follows that your privately used cloud storage, such as Dropbox, is not a private cloud. It is a public cloud.
That’s because there is no exclusive cloud behind Dropbox, created for you alone and used only by you. On the contrary: the cloud structure behind Dropbox is open to any company or person who wants to use it.
Community Cloud: The Community Cloud is in a sense a private cloud with a somewhat expanded circle of users. In this model, a specific community shares the cloud resources.
This community is typically made up of companies operating in the same business sector and having similar interests and needs.
The goal with the Community Cloud is to save costs compared to several individual private clouds.
Hybrid Cloud: Finally, there is the Hybrid Cloud model. It is a hybrid between private and public cloud.
With the hybrid cloud, companies decide to outsource only certain areas of their IT needs to public clouds. However, the company would prefer to leave certain data or processes in a private environment – so you use a private cloud for this. In most cases, considerations of data protection are in the foreground. For example, companies can store sensitive data in their private cloud and use a public cloud for other processes.
That would explain the four types of clouds. The following graphic summarises them again. You see: It’s mainly about how many people have access to the cloud structure.