Cloud is a term referring to accessing computer, information technology (IT), and software applications through a network connection. The term Cloud refers to a Network or Internet. In other words, we can say that Cloud is something, which is present at remote location
What is Cloud Computing?
Cloud Computing is the on-demand delivery of computer
Power,Database store,Application and other IT-resources through a cloud
services platform via the internet with pay-as-you-go pricing.
Benefit of Cloud Computing
Trade Capital expense for variable Expense
Instead of having to invest heavily in data center and server
before you know how your going to use them, you can only pay when you consume
computing resources and only pay for how much you consume.
Stop Guessing Capacity
Eliminate guessing on your infrastructure capacity needs.When you
make a capacity decision prior to deploying an application either sitting with
expensive resources or dealing with limited capacity. Using cloud you can access
as much or as little as you need.
Increase speed & agility
In a cloud Computing environment ,reduce the time it takes to make
IT resources available to your developer from weeks to just minutes.
Stop Spending Money on running and maintaining data
center.
Focus on project that differentiate your business, not the
infrastructure.
Go global in minutes
Easily deploy your application in multiple region around the
world.This means you can provide a lower latency and better experience for your
costumers.
Essential Cloud Computing Characteristics
On-demand self-service
Cloud services are expected to be available on-demand. A consumer
can unilaterally provision computing capabilities, such as server time and
network storage, as needed automatically without requiring human interaction
with each service provider.
Broad network access
Capabilities are available over the network and accessed through
standard mechanisms that promote use by heterogeneous thin or thick client
platforms (e.g., mobile phones, tablets, laptops, and workstations).
Resource pooling
The provider's computing resources are pooled to serve multiple
consumers using a multi-tenant model, with different physical and virtual
resources dynamically assigned and reassigned according to consumer demand.
There is a sense of location independence in that the customer generally has no
control or knowledge over the exact location of the provided resources but may
be able to specify location at a higher level of abstraction (e.g., country,
state or data center). Examples of resources include storage, processing, memory
and network bandwidth.
Rapid elasticity
Capabilities can be elastically provisioned and released, in some
cases automatically, to scale rapidly outward and inward commensurate with
demand. To the consumer, the capabilities available for provisioning often
appear to be unlimited and can be appropriated in any quantity at any time.
Measured service
Cloud systems automatically control and optimize resource use by
leveraging a metering capability at some level of abstraction appropriate to the
type of service (e.g., storage, processing, bandwidth and active user accounts).
Resource usage can be monitored, controlled and reported, providing transparency
for the provider and consumer.Cloud Deployment Models
Private Cloud: The Private Cloud allows systems
and services to be accessible within an organization. It may be owned, managed
and operated by organization or third party and it may exist on or off premises.
Benefits
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Private cloud operations are not available to general public so its provide high security and privacy.
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It provide more control on its resources because it is accessed only within an organization.
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Private cloud resources are not as cost effective as public clouds but they offer more efficiency.
Disadvantage
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Private cloud is only accessible locally and is very difficult to deploy globally
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Private cloud can be scaled only within capacity of internal hosted resources.
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To maintain the cloud, Organization requires more skilled and expertise.
Community Cloud: The Community Cloud allows systems and services to be accessible by group of organizations.It may be owned, manage and operated by one or more organizations. It may exist on or off premises.
Benefits
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Community cloud provides an infrastructure to share cloud resources and capabilities among several organizations.
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Community cloud is comparatively more secure than the public cloud.
Disadvantages
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Data might be accessible by others.
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Challenging to allocate responsibilities of governance, security and cost.
Public Cloud: The Public Cloud allows systems and services to be easily accessible to the general public. It may be owned, managed and operated by business or government organization. It exist on the premises of cloud provider.
Benefits
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Public cloud share same resources with large number of consumer, it has low cost.
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Easy to integrate public cloud with private cloud, hence gives consumers a flexible approach.
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Public cloud services are delivered through Internet, therefore ensures location independence.
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Public cloud is also based on pay-per-use model.
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Resources can be scaled up or down according the requirement.
Disadvantages
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Public cloud model, Resources are shared publicly, therefore low level of security.
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It is comparatively less customizable than private cloud.
Hybrid Cloud: The Hybrid Cloud is composition of public and private cloud. However, the critical activities are performed using private cloud while the non-critical activities are performed using public cloud.
Benefits
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It offers both features of public cloud scalability and private cloud scalability.
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Private cloud in hybrid cloud ensures higher degree of security.
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Public cloud are more cost effective than private, therefore hybrid cloud can have this saving.
Disadvantages
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Networking becomes complex due to presence of private and public cloud.
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It is necessary to ensure that cloud services are compliant with organization's security policies.
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Hybrid cloud model is dependent on internal IT infrastructure.
Cloud Service Models
Infrastructure as a Service (IaaS):
Infrastructure as a Service (IaaS) IaaS is the delivery of technology
infrastructure as an on demand scalable service. IaaS provides access to
fundamental resources such as physical machines, virtual machines, virtual
storage, etc
Advantages
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Consumer gets access to the Infrastructure to deploy their stuff.
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Manage OS, Storage, Network Component and deployed Application.
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Does not manage or control core Infrastructure.
Examle of Iaas: EC2
Platform as a Service (PaaS): Platform as a
Service (PaaS) PaaS provides the runtime environment for applications,
development & deployment tools, etc. PaaS provides all of the facilities
required to support the complete life cycle of building and delivering web
applications and services entirely from the Internet. Typically applications
must be developed with a particular platform in mind.
Advantages
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Consumer control over deployed application on a cloud
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No need to bother about the administration because it's the responsibility of cloud provider.
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No need to manage or control OS, Storage, Network Component .
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Very easy to scale up or down automatically based on application resource demands.
Example of Paas: Elastic Beanstalk
Software as a Service (SaaS): Software as a
Service (SaaS) SaaS model allows to use software applications as a service to
end users. SaaS is a software delivery methodology that provides licensed
multi-tenant access to software and its functions remotely as a Web-based
service.
Advantages
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No need to manage or control cloud infrastructure, OS, Storage, Network Component and individual application.
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They can be scaled up or down on demand.
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They are automatically upgraded and updated.
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Application make it available over a network.
Example of Saas: Microsoft Office 365, DropBox.
