35 Cloud Computing
Yatrik Patel
I. Objectives
Cloud computing is getting quite popular now a days in the world of ICT. Cloud computing refers to group of technologies that provides on-demand storage, data or computing power through the Internet. The concept has made huge impact on the technological application especially pertaining to the database and software applications. The cloud computing can be effectively implemented in various library application too. Different services and applications being used in library for providing services to the users can be effectively implemented using cloud computing. In this module we are going to study basics of cloud computing, its architecture and models as well as its applications to libraries.
II. Learning Outcomes
After going through this lesson, learners would attain knowledge about basics of cloud computing, its architecture and models as well as its applications to libraries. They would also learn how different services and applications that are being used in library for providing services to the users, can effectively be implemented using cloud computing.
III. Module Structure
1. Introduction
2. Definition: the Cloud Computing
3. Essential Characteristics of Cloud
3.1 On-demand self-service
3.2 Broad Network Access
3.3 Resource Pooling
3.4 Rapid Elasticity
3.5 Measured Service
4. Cloud Service Models
4.1 Infrastructure as a Service (IaaS)
4.2 Platform as a Service (PaaS)
4.3 Software as a Service (SaaS)
5. Cloud Deployment Models
5.1 Public Cloud
5.2 Private Cloud
5.3 Community Cloud
5.4 Hybrid Cloud
6. Advantages of Cloud Computing
7. Cloud Computing and IT based Library Services
8. Summary
9. References
1. Introduction
“Cloud computing” is not a new term, “Cloud” evolved with history of Internet itself. The idea of an “Intergalacti Ccomputer Network” was introduced in the sixties by J.C.R. Licklider (aka“Lick”) , who was responsible for enabling the development of ARPANET (Advanced Research Projects Agency Network) in 1969.
According to Larry Roberts, the primary ARPANET architect:
“Lick had this concept of the intergalactic network which he believed was everybody could use computers anywhere and get the data anywhere in the world. Although he didn’t have a clue how to build it. He didn’t have any idea how to make this happen. But he knew it was important, so he sat down with me and really convinced me that it was important and convinced me into making it happen.”
Other experts attribute the concept of cloud computing to computer scientist John McCarthy who proposed the idea of computation being delivered as a public utility which date back to the sixties.
In the past, computers were clustered together to form a single larger computer as common industrial practice that allowed users to configure computers to talk with each other using standard protocols to balance the computational load across the machines. As a user, one need not care about which CPU ran the program, and the cluster management software ensured that the “best” CPU at that time was used to run the code.
In the early 1990s, Ian Foster and Carl Kesselman came up with a new concept called “Grid”. With analogy to the electricity grid where users could plug into the grid and use a metered utility service. The same was applied for computing resources in case of grid computing wherein a user plug into a grid of computers and pay for what he/she uses. Grid computing expands the techniques of clustering where multiple independent clusters act like a grid due to their nature of not being located in a single domain.
The main bottleneck for moving cluster computing to grid computing was “data residency”. The computers in the cluster were usually physically connected to the disks holding the data, where as in grid the computational nodes could be situated anywhere in the world. It was fine having all that CPU power available, but the data on which the CPU performed its operations could be thousands of miles away, causing a delay (latency) between data fetched and its execution.
To avoid this bottleneck and to take grid further at the level of service, concept of the cloud computing was introduced, as such concepts of grid computing was evolved to a service offered by data centres.
In short the concept of “cloud” doesn’t only involve computers but encompasses
● First cloud around networking (TCP/IP abstraction);
● Second cloud around documents (WWW data abstraction); and
● The currently emerging cloud abstracts infrastructure complexities of servers, applications, data, and heterogeneous platforms.
2. Definition: the Cloud Computing
In generic terms Cloud Computing can be defined as “a model for enabling ubiquitous, 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.” (NIST) As far as a user is concerned, a cloud is a service that satisfies all of the following conditions:
● It is delivered over a telecommunications network;
● Users place reliance on the service for data access and/or data processing;
● The data is under the legal control of the user;
● Some of the resources on which the service depends are virtualised, For Examlple, the user has no technical need to be aware as to on which his applications are running or server running on which host is delivering the service, nor where the hosting device is located; and
● The service is acquired under a relatively flexible contractual arrangement.
The fundamental elements of cloud computing can be categorised as per following table
| Primary | Secondary |
|
• Virtualization • Grid technology • Service Oriented Architectures • Distributed Computing • Broadband Networks • Browser as a platform • Free and Open Source Software |
• Autonomic Systems • Web 2.0 • Web application frameworks • Service Level Agreements |
Table: 1 Fundamental elements of cloud computing.
The conceptual model of cloud promotes availability of resources, and is composed of five essential characteristics, three service models, and four deployment models.
3. Essential Characteristics of Cloud
As per definition of cloud computing by The National Institute of Standards and Technology (NIST) “five essential characteristics” of cloud computing are:
3.1 On-demand self-service (For Examlple, automated response by servers to direct requests by clients)
Cloud services such as email, applications, database, storage, computing, network or server service can be provided without requiring human interaction with each service provider. Cloud service providers that offer on demand self- services include Amazon Web Services (AWS), Microsoft, Google, IBM and Salesforce.com.
3.2 Broad Network Access (For Examlple, from anywhere, using any device) Cloud deliverables are available over the network and accessed through standard mechanisms that promote use by heterogeneous thin or thick client platforms such as smart phones, tablets, laptops and desktop PCs.
3.3 Resource Pooling (For Examlple, the provider allocates resources according to demand, rather than assigning resources to particular clients)
The provider’s computing resources are pooled together to serve multiple clients using multiple-tenant model, with different physical and virtual resources dynamically assigned and reassigned according to client demand. There sources include, among others, storage, processing, memory, network bandwidth, virtual machines, etc. This characteristic also gives a degree of location independence in wherein the client 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 regional data centre).
3.4 Rapid Elasticity (For Examlple, resources are scalable according to demand)
Usage of resources in cloud services can be rapidly and elastically provisioned, which can be also done automatically, to quickly scale out and rapidly released to quickly scale in. The capabilities available for provisioning often appear to be unlimited to the consumer and can be purchased in any quantity at any time.
3.5 Measured Service (For Examlple, resource usage is metered)
Cloud computing resource usage can be measured, controlled, and reported providing transparency for both the provider and consumer of the utilised service. Cloud computing services use a metering capability which enables to control and optimise resource (e.g., storage, processing, bandwidth and active user accounts) use. This implies that just like any other utility services, IT services are charged per usage metrics – pay per use.
4. Cloud Service Models
Cloud service providers offer their services according to several fundamental models: Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS) where IaaS is the most basic and each higher model abstracts from the details of the lower models.
4.1 Infrastructure as a Service (IaaS)
It is the capability provided to the user to enable processing, storage, networks, and other fundamental computing resources where the user is able to deploy and run arbitrary software, which can include operating systems and applications. The user does not manage or control the underlying cloud infrastructure but has control over operating systems, storage, deployed applications, and possibly limited control of select networking components.
4.2 Platform as a Service (PaaS)
PaaS provides an application platform, or middleware, as a service on which developers can build and deploy custom applications. Common solutions provided in this tier range from APIs and tools to database and business process management systems to security integration, allowing developers to build applications and run them on the infrastructure that the cloud vendor owns and maintains.
4.3 Software as a Service (SaaS)
The applications are accessible from various client devices through a thin client interface such as a web browser (e.g., web-based email). The user does not manage or control the underlying cloud infrastructure including network, servers, operating systems, storage, or even individual application capabilities, with the possible exception of limited user-specific application configuration settings.
Fig.1: Cloud Service Models
Apart from basic service models, Network as a Service (NaaS) and Communication as a Service (CaaS) were officially included by ITU (International Telecommunication Union) as part of the basic cloud computing models, recognized service categories of a telecommunication-centric cloud ecosystem.
5. Cloud Deployment Models
There are four primary cloud deployment models. Each deployment model necessarily exhibits the previously discussed essential characteristics. The basic differences lie in the scope and access of cloud services, as they are made available to end users.
5.1 Public Cloud
A public cloud is a publicly accessible cloud environment owned by a third- party cloud provider. The deployment of a public cloud computing system is having two major characteristics, the first one is public availability of the cloud service offering and the other is the public network that is used to communicate with the cloud service. The cloud services and cloud resources are procured from very large resource pools that are shared by all end users. If a cloud provider runs several data centers, for instance, resources can be assigned in such a way that the load is uniformly distributed between all centers. Generally, public cloud service providers like Amazon AWS, Microsoft and Google own and operate the infrastructure and offer access only via Internet.
5.2 Private Cloud
Private cloud is cloud infrastructure operated solely for a single organization, whether managed internally or by a third-party and hosted internally or externally. Self-run cloud infrastructures are generally capital intensive. They have a significant physical footprint, requiring allocations of space, hardware, and environmental controls. These assets have to be refreshed periodically, resulting in additional capital expenditures. Generally private clouds are not preferred because users still have to buy, build, and manage them.
5.3 Community Cloud
A community cloud is similar to a public cloud except that its access is limited to a specific community of cloud consumers. In this delivery model, cloud infrastructure is being shared between several organizations from a specific community with common objectives. It can be managed internally or by a third- party and hosted internally or externally. The costs are spread over fewer users than a public cloud (but more than a private cloud), so only some of the cost savings potential of cloud computing are realized.
5.4 Hybrid Cloud
A hybrid cloud is a cloud environment of two or more different cloud deployment models, offering the benefits of multiple deployment models. Hybrid cloud can also mean the ability to connect collocation, managed and/or dedicated services with cloud resources. A hybrid cloud service can be defined as a cloud service that is composed of combination of private, public and community cloud services, offered through different service providers. A hybrid cloud service crosses isolation and provider boundaries so that it can’t be simply put in one category of private, public, or community cloud service. It allows one to extend either the capacity or the capability of a cloud service, by aggregation, integration or customization with another cloud service.
Fig.2: Conceptual Framework for Cloud Computing
6. Advantages of Cloud Computing
The advantages of cloud computing depends on case to case basis. However, following are the general benefits:
• Assured maximum availability of data, application and infrastructure;
• Need to pay only for what has been used (For Examlple, Bandwidth, Resources);
• Relieves burden of IT staff within organization, as routine jobs are being handled by service providers; and
• Easily scalable as per requirement of organization.
General disadvantages of cloud are dependency upon network connectivity, security, legal issues (ownership of data), latency etc. which need to be carefully reviewed.
7. Cloud Computing and IT based Library Services
Most common library services can be scooped into following three categories.
Data: Bibliographic, Technical, Access, Licence;
Content: Collection, Subscription, Digital, Print, Publishing; and
Services: Library as a place, content-access, content-creation, research, preservation.
As libraries are having service-oriented mission they are in a position to adopt cloud computing. Libraries (or librarians) are in constant search of finding proper solution within limited resources, moreover the outreach of service is quite dependent on support of external or internal computing (IT) support staff. It has been always difficult for libraries to have IT support staff with expertise on advance IT management. This situation makes SaaS, PaaS or IaaS approach tempting for library professionals to move towards cloud computing for providing better library services.
Libraries have been adopting cloud-based solutions services like electronic journal access management, statistics tracking, digital library hosting and now trend is coming up for hosted library management systems.
The use of SaaS in libraries dates back to early 2000 with the establishment of companies like Serials Solutions (http://serialssolutions.com). There are also examples of availability of hosting platforms like INFLIBNET’s OJAS (Open Journal Academic System) available at http://www.inflibnet.ac.in/ojs/, For Institutional repositories there is Dura Cloud (http://duracloud.org/), for open access publishing BioMed Central (http://www.biomedcentral.com/)are well- known platform.
One of the pioneer for IaaS cloud services is Amazon Elastic Computing Cloud (EC2) which offers IT infrastructure with differently sized servers using a choice of operating systems, including several flavours of Linux and Windows. EC2 provides organizations with unlimited storage using S3 service, the ability to take snapshots of both data and servers, and the ability to include EC2 servers in an organization’s private network. A full catalogue of EC2 features is available on the EC2 website (http://aws.amazon.com/ec2/).
In India, under NMEICT (National Mission on Education through Information and Communication Technology), IIT Delhi has been entrusted responsibilities to establish common computer infrastructure for the academic needs with a good bandwidth access via NKN (National Knowledge Network) Besides this, INFLIBNET Centre is also offering several cloud based services (DSpace hosting, virtual and physical server hosting) at its data centre located at Gandhinagar.
8. Summary
By using cloud, library services can be made online without worrying about correct versions of platforms or the underlying technology. It also gives facility to induce new applications quickly without having to focus on identifying available server space or configuration and IT-based library services can be delivered much more quickly than when using locally-based hardware or software.
Libraries can make choices about the allocation of resources and to offer better service than would be possible if relying on in-house solutions.
9. References
- Wallis, Paul; A brief history of cloud computing: Is the cloud there yet?: Cloud Computing Journal (http://cloudcomputing.sys– con.com/node/581838)
- Mitchell, Eric, Ph.D.: Using cloud services for library IT infrastructure : Code4Lib Journal (http://journal.code4lib.org/articles/2510).
- Cloud computing : Wikipedia Article (http://en.wikipedia.org/wiki/Cloud_computing)
- NIST cloud computing program (http://www.nist.gov/itl/cloud/index.cfm)
- Objectives : INFLIBNET Centre (http://www.inflibnet.ac.in/about/objective.html)
- http://www.cloud-competence-center.com/understanding/cloud- computing-deployment-models/