Cloud is an metaphor for internet used here. Computing is an IT activity carried out. Customers do not have physical infrastructure. Consume resources as a service and only pay for those resources used. Information that a digitized system has to offer is provided as service.
Empowerment of end users. Resources are hosted by service provider on behalf of entity. Data processed by resources is private to the entity and its associates. It increases the speed of application development. API accessibility to softwaresthat enables machine to interact with cloud software. Cost is reduced. Device and location independence. Peak load capacity increases.
There are three fundamental service models :- SaaS PaaS IaaS
Itprovides a software that is specific to end users requirement. The host manages the software and infrastructure runs the software and stores data. Consumers cannot control software beyond the usual configure settings . Host regularly back up all data.
Itconsists of software development and deployment platforms known as cloud platforms. Host provides complete software development and run time environment. Infrastructure include a database and identity management or access control software.
It consists of hardware infrastructure located in the cloud. It includes cloud storage,servers and networks and is also known as hardware as a service. It is used to run software or simply store data. Consumers can be end users developers or other cloud providers.
There are three types of deployment models:- Public cloud Private cloud Community cloud Hybrid cloud
Public clouds are cloud systems that are made available to any member of non exclusive group. These services are or offered on a pay-per- use model
Private clouds are cloud systems that are accessible by a single consumer or exclusive group. It is also known as internal or corporate clouds. These clouds are private because of the need for system and data security.
These are cloud systems that are available only to a specific group of entities which share common purpose. These clouds are managed by community or third party. It is neither private nor public as unlike private it isn’t narrowly exclusive and unlike public entities outside the community although can benefit from the service but cannot become consumers.
It is a combination of two or more public private and community clouds that are used on day to day basis. It contains larger pool of resources that can be made available to their consumers. It is also called “cloud of clouds”
It is divided into two sections:- Front end :- It is the side that client or the computer user sees. Backend:- It is the cloud section of the system
Itis a database that runs on cloud computing platform. There are two primary methods to run a database n cloud:- Virtual machine image:- cloud platforms allow users to purchase virtual machine instances for limited time it is possible to run database on these virtual machines.
Database as a service :- Some cloudplatforms offer options for using a databaseas a service, without physically launching avirtual machine instance for the database.In this configuration, application owners donot have to install and maintain thedatabase on their own. Instead, thedatabase service provider takesresponsibility for installing and maintainingthe database, and application owners payaccording to their usage
Reduced costs:- Cloud services paid for on a usage basis can be financially advantageous for a consumer when compared to the outright purchase, or long-term rental, of what would be a big-budget item. Up-to-date software:- SaaS consumers can always have the most up-to-date software, because versioning is controlled centrally by the cloud provider, and when they make a new release it is automatically available to every user.
Improved access:- Cloud computing involves using the Internet, and this can provide access from multiple locations and many different types of user device. Sharing and co-operation:- Cloud services are advantageous, when compared to PCs and local servers, for activities that require co- operation among distributed groups.
Privacy and security:- Since data is stored on a cloud providers systems, and possibly in a location that may not be known by the consumer, there can be data-privacy and security issues. Regulatory and customer requirements:- There are some issues that may prevent the use of cloud services. Service-provider outages:- Any accidental downtime, or outage, of cloud systems can affect some or all of the provider’s tenants, and so this can deprive many users of access to their IT systems.