Cloud computing has been emerging now since several years. However, for a lot of people, it still is a concept that is not very clear. Let me explain a common cloud computing concept : the public cloud.
What is a public cloud?
If you would ask me to write down a definition of a public cloud, I would say : "A public cloud is an IT infrastructure, managed by a third pary, that is accessible through the internet."
By default, the proposed resources offered by this type of cloud, are - most of the time - shared amongst the different customers of the service. Even though these resources are shared, a certain isolation exists between each customer. This type of cloud allows a large flexibility in terms of resources.
Two models
Generally speaking, there exist two types of models:
- A monthly recurring cost is defined beforehand and allows to master the costs.
- A cost which is calculated based on the usage volume of the resources. In this case, the cost is thus variable and evolves with the usage of the resources.
The first model allows to master the monthly costs from the start. The second model offers more flexibility but can become more costly in case of intensive usage or in case of lack of any fixed limitations.
Independently of the model you choose, the resources available can be increased or decreased by the provider, following the needs of the customers.
A public cloud is a good starting point for small startups because they don't require any investment in an expensive IT infrastructure. The cost can directly be spread over time. On the other hand, the cloud can be interesting for companies that dispose of a proper IT infrastructure that is at the end of it's maintenance cycle. By moving to a cloud solution, they can unburden from the renewal costs of the materials and the recurring maintenance fees.
