In IT, just like in the meteorology, we cannot talk about the one and only meaning of cloud. In general we could say that depending on the point of view cloud (or cloud service) may just as much refer to the shared pools of resources (networks, servers, storage facilities) as to the applications and services built upon them.
From the service models point of view, cloud services are either:
- IaaS (Infrastructure as a Service)
Provides processing, storage and network resources so the consumer may
build a virtual infrastructure with virtual machines (running operating
systems of the consumer's choice) interconnected in virtual networks.
- PaaS (Platform as a Service)
Provides facilities (libraries, tools, services etc.) for the consumer to
create applications that could be deployed on the provided platform.
Consumer has full control over the deployed applications and may have the
opportunity to adjust some of the configuration settings for the
- SaaS (Software as a Service)
The capability provided to the consumer is to use applications made by the
provider and running on a cloud infrastructure. Most of the cases, the
consumer only has access to some user specific settings inside the
From the deployment models point of view, there are:
- Private clouds, where the cloud infrastructure is provisioned for exclusive use by a single organisation.
- Community clouds, where the cloud infrastructure is provisioned for exclusive use by a specific community from organisations that have shared concerns.
- Public clouds, where the cloud infrastructure is provisioned for open use by the general public. The infrastructure exists on the premises of the cloud provider and may be owned/managed/operated by an academic, government or business organisation or some combination of them.
- Hybrid clouds, that is a composition of two or more distinct cloud infrastructures (of the former three types). These remain unique entities, but are bound together by some technique to ensure the portability of data and applications (e.g. to achieve load balancing between clouds).
Read more about the cloud service NIIF Institute offers.