Now a day’s Cloud computing is emerging field because of its Performance, high availability, at low cost.
Cloud:Cloud is kind of Centralized database where many organizations store their data, retrieve data and possibly modify data. It will be present in the remote location. Cloud can provide services over the network.
Ex: WAN, LAN and VPN.
In the cloud many Services are provided to the client by cloud. Data store is main future that cloud service provides to the big organization to store huge amount of data. To prevent unauthorized access, it can be done with the help of a distributed scheme by using homomorphism token to provide security of the data in cloud. The cloud is support for data redundancy means clients can insert, delete or can update data so there should be security mechanism which ensure integrity of data.
Cloud Computing:Cloud computing provides a new way to supplement the current consumption and delivery model for IT services based on the internet. It refers to manipulating, configuring and accessing the applications. It refers online data storage, infrastructure and application.
To make cloud computing flexible and accessible to the end users, we are using certain services and models behind it.
1. Deployment Models
2. Service Models
Deployment Models: It defines the type of access to the cloud. They are four types of clouds.
1. Public Cloud
2. Private Cloud
3. Hybrid Cloud
4. Community Cloud
1. Public Cloud:
It allows the systems and services to be easily accessible to the general public. Public cloud is less secure because of its openness.Ex: e-mail.
It is made to available for general public by a service provider who hosts the cloud infrastructure. In this model customers have no visibility and control over the infrastructure is located. The important thing is all customers in the public cloud share the same infrastructure pool with limited configuration, security protections and availability services.
Public cloud customers benefit from economies of scale, because infrastructure costs are spread across all users, allowing each individual client to operate on low-cost, pay-as-you-go model.
When we will use public cloud?
• Workload for applications is used by lots of people.
• Need to test and develop app code.
• Need to increment the capacity.
2. Private Cloud:
It will allow the system and services to be accessible within the organization. It offers increase security because of its private nature. Private cloud is dedicated to particular organization. It allows business to host applications in the cloud, while addressing concerns regarding data security and control, which is often looking in a public cloud environment. It is not shared with other organizations, whether managed internally or by third-party and it can be hosted internally or externally.
Two variations in private cloud
1. On-premises private cloud
2. Externally hosted private cloud
1. On-premises private cloud: This type of cloud is hosted with in the organizations own facility. This cloud is best used for applications that require complete control and configurability of the infrastructure and security.
2. Externally hosted private cloud: These clouds are used by externally one organization, but are hosted by third-party specializing in cloud infrastructure. Full guarantee of privacy.
Private cloud is more expensive and secure compared to public cloud.
When we will use private cloud?
• Need authority but want cloud efficiencies.
• Want consistency across services.
• We should have more server capacity then your organization use.
• Data center must become more efficient.
3. Hybrid cloud:
It is a mixture of public and private cloud. The critical activities are performed using private cloud and the non-critical activities are performed by public cloud. In this cloud we can calculate the gain and losses, third-party cloud providers in either flexibility of computing. In this model users typically outsource non-business-critical information and processing to the public cloud, while keeping the business services and data in their control.
The cloud infrastructure exists of number of clouds of any type, but the clouds have ability through their interfaces to allow data or applications to be moved from one cloud to another.
4. Community Cloud:
It allows systems and services to be accessible by group of organizations with similar interests and requirements. This may help limit the capital expenditure cost for its establishment as the costs are shared among the organizations. This operation may be in-house or with a third-party on the premises.
These are the some of the reference model which the cloud computing is based.
There are three main models
1. Infrastructure as a Service (IaaS)
2. Platform as a Service (PaaS)
3. Software as a Service (SaaS)
They are so many other service models are there like
NaaS (Network as a Service)
BaaS (Business as a Service)
IaaS (Identity as a Service)
DaaS (Database as a Service)
1. Infrastructure as a Service (IaaS):
This is the most basic level of service. Each model inherits the security & management mechanism from the underlying model. It provides the access to fundamental resources such as physical machines, virtual machines and virtual storage etc.
2. Platform as a Service (PaaS):
It provides the runtime environment for applications, development & development tools etc. Consumers purchase access to the platforms, enabling them to deploy their own software and applications in cloud. The operating systems and network access are not managed by the consumer and there might be to which applications can be deployed.
3. Software as a Service (SaaS):
It allows to use software applications as a service to end users. Consumers purchase access to the platforms, enabling then to deploy their own software and applications in the cloud. Where the information for the interaction between the consumer and the service is hosted as part of the service in the cloud.