30 June 2020 Reading time: 1 minute

What are private, public and hybrid clouds


To build a cloud infrastructure, companies can use their own equipment, rent a ready-made service from a provider or combine both. Depending on this, clouds are divided into three types:

  • A private cloud is an infrastructure intended for use by one organization. The equipment may be located on the premises of the company itself or placed on rented space in a data center.
  • A public cloud is used by many companies simultaneously. It is a ready-made service offered by providers such as Amazon. In case of a public cloud, customers have no physical access to the equipment.
  • A hybrid cloud is a combination of private and public infrastructure. A part of equipment may be owned by the user, while the other part may be in a public service.

Let us see how each of these types of cloud infrastructure is used.

Read more below:

What is a private cloud

Private cloud is deployed on the user's own equipment and is under the user’s control

In a private cloud, the infrastructure is owned by the user and can be fully managed.

Advantages of a private cloud

Efficient use of the organization's computing resources. Cloud technologies allow rational redistribution of load between physical equipment and rational use of own capacities.

Independence. The organization is confident that all computing resources are at its disposal. The infrastructure will not be affected by errors or cloud neighbors' processes.

Easy access to computing resources: if the equipment is located on the company's premises, it allows managing computing resources without having to use an Internet connection.

Higher security: rivate cloud is entirely under the supervision of one organization. Administrators can monitor the infrastructure and keep it protected against unauthorized access.

Can be used under legal restrictions. Due to legal requirements, companies do not always have the opportunity to use the services of public cloud providers. In that case, a private cloud will be the only solution.

Disadvantages of a private cloud

Difficult to design: on the outset, it is difficult to determine the required amount of computing resources and how to organize the infrastructure optimally.

Expensive to build: to create a private cloud, you need to invest in equipment and licenses, spend resources on training specialists.

Expensive to operate: you need to independently monitor the private cloud, update the hardware, renew software licenses. All this requires money and the work of specialists.

Hard to scale: the capacity is limited by equipment resources. If the demand for computing resources grows over time, much work will have to be done to purchase and configure the equipment.

Examples of private cloud use

Large organizations. Private clouds are preferred by  large and medium-sized companies that have sufficient computing power of their own. In this case, the cloud will reduce hardware and software costs.

Companies that need to control their resources. Large software developers, government organizations, large industrial companies. Private clouds are the choice of everyone who cares about full access to the infrastructure and wants to be guaranteed to receive the service regardless of third parties and Internet connections.

Companies that need support for several large databases In a private cloud, the equipment is physically close by. It speeds up the work with the databases. In addition, it is easier to control backups in a private cloud.

Organizations with tightly planned budgets for IT infrastructure, such as the public sectors. The cost of a private cloud is easier to manage as the service cost does not depend on tariffs of external providers.

What is a public cloud

Public cloud: users connect to the provider’s computing resources

Public cloud — a ready-made IaaS or PaaS service. Users connect to computing resources via the Internet. Examples of a public cloud are Amazon, Microsoft Azure, Google Cloud. Provider undertakes most of physical infrastructure maintenance. 

Advantages of public clouds

Easy to use. All you need to use the infrastructure is Internet access: spending time to install hardware and software, design processes or train your employees is not required.

Flexible billing and no long-term commitments. A company may increase or decrease the expenses on a public cloud at any time. All you need to do is to select an appropriate billing package. In addition, if the service becomes irrelevant, you can refuse it.

Reducing IT maintenance costs. Public cloud is maintained by the provider. This reduces the organization's payroll, license and equipment maintenance costs.

Disadvantages of public clouds

Low data security. Public cloud clients cannot control where their data are located, how backup is performed at the provider level and which neighbors the physical server is shared with.

Dependence on Internet connection. The performance and availability of a public cloud is directly related to the throughput capacity and stability of the Internet connection.

Dependence on an external organization. The provider may suffer from an accident, a data leak or close the service altogether. It is difficult for public cloud users to influence such situations.

Not profitable in the long term and for large-scale projects. For large organizations with constant demand for capacity, public cloud is often unprofitable because they have to regularly pay infrastructure bills that include the provider’s profit.

Tangible assets are not acquired. The Company does not take possession of any physical equipment that could be part of its fixed capital.

Examples of public cloud use

For project testing. ВIt is risky to invest in the purchase of equipment for a new service: no one knows how long the project will exist. It is more profitable to test ideas in a public cloud.

Fluctuating demand on computing power. In seasonal business and for other temporary work it is advisable to rent capacity from a provider. In this case, you can only pay for the time you use the service.

In small and medium businesses. Public clouds are usually financially more accessible for small companies and do not require risky investments. They are used when it is not profitable to maintain your own infrastructure.

To switch from capital to operating expenses. Sometimes a private cloud is preferred in terms of financial management. There is no need to calculate the service life of the equipment, to accrue depreciation, or to renew the fleet.

What is a hybrid cloud

Hybrid cloud combines private and public infrastructure

Hybrid infrastructure uses both own computing resources and leased capacity. For example, a company can deploy an IP telephone service on its server and store call records with the provider. This solution combines the advantages and disadvantages of private and public clouds.

Advantages of a hybrid cloud

The ability to allocate resources optimally. The organization can maximize the efficiency of its capacity use. For example, deploy a private cloud for daily tasks while using the public cloud as a backup solution in case of high load.

Optimization of infrastructure costs. Companies that want to save money can take part of the infrastructure to the public cloud to avoid buying equipment.

The ability to combine performance with high levels of protection. You can deploy shared applications or create backups in a public cloud. Meanwhile, data that require high security will be placed in a private cloud.

Disadvantages of a hybrid cloud

It is difficult to integrate public and private clouds as they often use different technologies.

Increased threat of data loss, for example when migrating an application from one cloud to another.

Reduced fault tolerance when hosting a single application. Even equipment with similar characteristics can demonstrate different performance in the private and public sector of hybrid infrastructure. This will cause problems with applications that are distributed in this cloud.

High accident risk: the more complex the system, the more vulnerabilities it has. In a hybrid infrastructure, the connection between a private and public cloud can fail.

Examples of hybrid cloud use

Software developers often face high network loads, for example, during the development phase. In this case, when the load is low, own equipment will be sufficient, and at peak times you can successfully use public clouds.

Companies that need extra capacity quickly. Sometimes hybrid clouds are the only option when more resources are required: you can quickly use the computing capacity of the public infrastructure sector.

Companies that want to test cloud technology: partially expand infrastructure by means of the cloud to try out new features.

Private, public and hybrid clouds: a comparison

Private clouds
Public clouds
Hybrid clouds
Entry threshold
High: you need to design the system, purchase equipment, and engage qualified specialists
Low: to use the computing capacity you only need to pay for the service
High: requires not only deploying a private cloud, but also configuring its integration with the public cloud.
Operating costs
High:owner bears all costs. You need to update your equipment and licenses independently.
Low:the provider assumes all the costs.
Medium: the provider assumes part of the infrastructure maintenance costs.
Complexity of maintenance
High: you need to monitor the infrastructure and fix problems independently.
Low: the provider monitors the equipment and the software platform.
High: you need to maintain the private sector of the cloud and interact with providers independently
Scaling speed
Low: you need to buy and configure the equipment
High: extra capacity can be received immediately on request
High: you can scale the capacity quickly through the public cloud sector
High, when designed correctly: the entire infrastructure is controlled by the owner
Low: you cannot control many important issues because they are managed by the provider
High when designed correctly: important services can be placed into the private cloud sector and fully controlled

Statistics: what types of cloud infrastructure are used in the world

In its 2020 study, Flexera found out  what types of cloud infrastructure companies in the world use.

Cloud use strategies. Source: Flexera

Most organizations - 87% of those surveyed - prefer hybrid infrastructure. This may be due to the desire of companies to get as much benefit as possible from the combination of private and public clouds.

Public clouds are used by 12% of organizations. Half of them are hosted by several providers at once. 1% of the companies surveyed host their projects exclusively in a private cloud.