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| Cloud Computing Introduction | IndianTechnoEra |
Introduction to Cloud Computing
What is Cloud Computing ?
Cloud Definitions
Definition from NIST (National Institute of Standards and Technology)
Cloud computing is a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction.
This cloud model promotes availability and is composed of five essential characteristics, three service models, and four deployment models.
Definition from Wikipedia
Cloud computing is Internet-based computing, whereby shared resources, software, and information are provided to computers and other devices on demand, like the electricity grid.
Cloud computing is a style of computing in which dynamically scalable and often virtualized resources are provided as a service over the Internet.
Definition from Whatis.com
The name cloud computing was inspired by the cloud symbol that's often used to represent the Internet in flowcharts and diagrams. Cloud computing is a general term for anything that involves delivering hosted services over the Internet.
Definition from Berkeley
Cloud Computing refers to both the applications delivered as services over the Internet and the hardware and systems software in the datacenters that provide those services.
The services themselves have long been referred to as Software as a Service (SaaS), so we use that term. The datacenter hardware and software is what we will call a Cloud.
When a Cloud is made available in a pay-as-you-go manner to the public…… The service being sold is Utility Computing.
Definition from Buyya
A Cloud is a type of parallel and distributed system consisting of a collection of interconnected and virtualized computers that are dynamically provisioned and presented as one or more unified computing resources based on service-level agreements established through negotiation between the service provider and consumers.
Cloud Computing
Central ideas - Don’t tell me details!! I DON’T CARE!!
Utility Computing
SOA - Service Oriented Architecture
SLA - Service Level Agreement
Central ideas
What does the mean of Central ideas?
Don’t tell me details!! I DON’T CARE!!
Perspective from user :
Users do not care about how the works are done
Instead, they only concern about what they can get
Users do not care about what the provider actually did
Instead, they only concern about their quality of service
Users do not want to own the physical infrastructure
Instead, they only want to pay as many as they used
What does user really care ?
They only care about their “Service”
Utility Computing
What does the mean of utility computing?
One service provisioning model
Service provider makes computing resources and infrastructure management available to the customer as needed, and charges them for specific usage rather than a flat rate.
Like other types of on-demand computing , the utility model seeks to maximize the efficient use of resources and/or minimize associated costs.
What is service?
Service is what you connect together using Web Services.
Service is the endpoint of a connection.
Functionalities of service :
A service should be well-defined
A service should be self-contained
A service should not depend on the context or state of other services.
What is web service?
Definition :
Web service is self-describing and stateless modules that perform discrete units of work and are available over the network
Web service providers offer APIs that enable developers to exploit functionality over the Internet, rather than delivering full-blown applications
Web Services Description Language (WSDL) :
Expressed in XML which include both data type and messages
Four types of operations :
One-way - Messages sent without a reply required
Request & response - Sending and replying messages
Solicit response - A request for a response
Notification - Messages sent to multiple receivers
Service Oriented Architecture
Definition
Service Oriented Architecture (SOA) is essentially a collection of services which communicate with each other
Contain a flexible set of design principles used during the phases of systems development and integration
Provide a loosely-integrated suite of services that can be used within multiple business domains
Approach
Usually implemented by Web Service model
Quality Of Service
What is quality of service?
Quality of Service (QoS) is a set of technologies for managing network traffic in a cost effective manner to enhance user experiences for home and enterprise environments.
Now QoS becomes to a broad term that is used following areas :
Customer care evaluations
Technological evaluations
Customer care evaluations
QoS is usually measured in terms of issues that have a direct impact on the experience of the customer
Only issues that produce a negative effect on the goods and services received by the customer come under scrutiny
Technological evaluations
QoS has to do with the efficient operation of various systems
This can lead to adjusting procedures or adapting software programs and code to achieve the desired effect while making a more efficient use of available resources
Service Level Agreement
What is service level agreement (SLA)?
A service-level agreement (SLA) is a contract between a network service provider and a customer that specifies, usually in measurable terms (QoS), what services the network service provider will furnish
Common content in contract
Performance guarantee metrics
Up-time and down-time ratio
System throughput
Response time
Problem management detail
Penalties for non-performance
Documented security capabilities