CLOUD COMPUTING-BASICS

INTRODUCTION

• Cloud computing is an information technology (IT) enabling ubiquitous access to shared pools of configurable resources (such as computer networks, servers, storage, applications and services), which can be rapidly provisioned with minimal management effort, often over the Internet. 

• Cloud computing allows users and enterprises with various computing capabilities to store and process data either in a privately-owned cloud, or on a third-party server located in a data center - thus making data-accessing mechanisms more efficient and reliable. 

• Cloud computing relies on sharing of resources to achieve coherence and economy of scale, similar to a utility.

• Cloud computing allows companies to avoid or minimize up-front IT infrastructure costs. 

• As well, third-party clouds enable organizations to focus on their core businesses instead of expending resources on computer infrastructure and maintenance. 

• Proponents also claim that cloud computing allows enterprises to get their applications up and running faster, with improved manageability and less maintenance

•  Cloud providers typically use a "pay-as-you-go" model. This could lead to unexpectedly high charges if administrators are not familiarized with cloud-pricing models.

• In 2009 the availability of high-capacity networks, low-cost computers and storage devices as well as the widespread adoption of hardware virtualization, service-oriented architecture, and autonomic and utility computing led to a growth in cloud computing.

• In 2013 it was reported that cloud computing had become a highly demanded service or utility due to the advantages of high computing power, cheap cost of services, high performance, scalability, and accessibility - as well as availability.

• The main enabling technology for cloud computing is virtualization. 

• Virtualization software separates a physical computing device into one or more "virtual" devices, each of which can be easily used and managed to perform several tasks at a time

• Cloud computing is a kind of grid computing it has evolved by addressing the QoS (quality of service) and reliability problems. 

• Cloud computing provides the tools and technologies to build data/compute intensive parallel applications with much more affordable prices compared to traditional parallel computing techniques

Characteristics

1. Agility for organizations may be improved
2. Cost reductions are claimed by cloud providers
3. Device and location independence enable users to access systems using a web browser regardless of their location or what device they use
4. Maintenance of cloud computing applications is easier
5. Productivity may be increased when multiple users can work on the same data simultaneously
6. Security can improve due to centralization of data, increased security-focused resources

"five essential characteristics"

• On-demand self-service.
• Broad network access
• Resource pooling
• Rapid elasticity.
• Measured service.

SERVICE MODELS

1-Infrastructure as a service (IaaS)

• refers to online services that provide high-level APIs used to deference various low-level details of underlying network infrastructure like physical computing resources, location, data partitioning, scaling, security, backup etc

2-Platform as a service (PaaS)

• PaaS vendors offer a development environment to application developers

3-Software as a service (SaaS)

• In the software as a service (SaaS) model, users gain access to application software and databases

4-Security as a service (SECaaS)

• a large service provider integrates their security services into a corporate infrastructure on a subscription basis more cost effectively than most individuals or corporations can provide on their own, when total cost of ownership is considered

5-Mobile "back end" as a service (MBaaS)

•  web app and mobile app developers are provided with a way to link their applications to cloud storage and cloud computing services with application programming interfaces (APIs) exposed to their applications and custom software development kits (SDKs)

6-Server less computing

• Server less computing is a cloud computing code execution model in which the cloud provider fully manages starting and stopping virtual machines as necessary to serve requests, and requests are billed by an abstract measure of the resources required to satisfy the request, rather than per virtual machine, per hour

Credit-Wikipedia