Cloud computing is an Internet-based computing in which shared the pool of resources are available over a broad network access, these resources can e provisioned or released with minimum management efforts and service provider interaction.
There are four types of cloud:
1. Public cloud
2. Private cloud
3. Hybrid cloud
4. Community cloud
Public cloud are managed by third parties which provide cloud services over the internet to public, these services are available as pay-as-you-go billing mode.
They offer solutions for minimizing IT infrastructure costs and act as a good option for handling peak loads on the local infrastructure. They are a goto option for small enterprises, which are able to start their businesses without large upfront investments by completely relying on public infrastructure for their IT needs.
A fundamental characteristic of public clouds is multitenancy. A public cloud is meant to serve multiple users, not a single customer. A user requires a virtual computing environment that is separated, and most likely isolated, from other users.
Private cloud :
Private clouds are distributed systems that work on a private infrastructure and providing the users with dynamic provisioning of computing resources. Instead of a pay-as-you-go model as in public clouds, there could be other schemes in that take into account the usage of the cloud and proportionally billing the different departments or sections of an enterprise.
The advantages of using a private cloud are:
- Customer information protection: In private cloud security concerns are less since customer data and other sensitive information does not flow out of a private infrastructure.
- Infrastructure ensuring SLAs: Private cloud provides specific operations such as appropriate clustering, data replication, system monitoring and maintenance, and disaster recovery, and other uptime services.
- Compliance with standard procedures and operations: Specific procedures have to be put in place when deploying and executing applications according to third-party compliance standards.This is not possible in case of public cloud.
Hybrid cloud is a heterogeneous distributed system resulted by combining facilities of public cloud and private cloud. For this reason they are also called heterogeneous clouds.
A major drawback of private deployments is the inability to scale on demand and to efficiently address peak loads. Here public clouds are needed. Hence, a hybrid cloud takes advantages of both public and private cloud.
Community clouds are distributed systems created by integrating the services of different clouds to address the specific needs of an industry, a community, or a business sector.
In community cloud, the infrastructure is shared between organization which have shared concerns or tasks. The cloud may be managed by an organization or a third party.
Sectors that use community clouds are:
- Media industry: Media companies are looking for quick, simple, low-cost way for increasing efficiency of content generation.Most media productions involve an extended ecosystem of partners. In particular, the creation of digital content is the outcome of a collaborative process that includes movement of large data, massive compute-intensive rendering tasks, and complex workflow executions.
- Healthcare industry: In healthcare industry community clouds are used to share information and knowledge on the global level with sensitive data in the private infrastructure.
- Energy and core industry: In these sectors, the community cloud is used to cluster set of solution which collectively addresses management, deployment, and orchestration of services and operations.
- Scientific research: In this organization with common interests of science share large distributed infrastructure for scientific computing.