Cloud Service Models

The following service models have different strengths and are suitable for different customers and business objectives. In general, interoperability and portability of customer workloads are more achievable in the Infrastructure as a Service (IaaS) service model because the building blocks of this service are relatively well-defined.

A business can now access the entire cloud computing infrastructure it requires as a service for all it uses wherever they are, on whatever device they use. This is called infrastructure as a service (IaaS). User applications remain the same running on more reliable cloud infrastructure; this is when most business will start to use cloud. Apps will be migrated as the existing infrastructure reaches the end of its life. PaaS builds on the power of IaaS as a platform to make it easier to collaborate and develop software. SaaS is explained as a set of fully serviced software running on a fully serviced infrastructure.

There is no longer the need of upfront investments for new business application packages. So cloud can be all the three models with IaaS at the core.

• Cloud Software as a Service (SaaS): The user uses the provider’s applications running on a cloud infrastructure. The applications or software services are accessible from various client devices through a thin client interface such as a Web browser. The consumer does not control or manage the underlying cloud infrastructure including servers, network, storage, operating systems, or individual application capabilities. It might be possible for the user to specify application configuration settings.
• Cloud Platform as a Service (PaaS): This service allows the user to deploy onto the cloud infrastructure applications that the user acquired or created using programming languages and tools supported by the provider. The consumer does not control or manage the underlying cloud infrastructure including servers, network, operating systems, or storage, but has control over the deployed software applications and possibly application hosting environment configurations.
• Cloud Infrastructure as a Service (IaaS): This service enables the user to use processing, networks, storage, and other fundamental computing resources, and to deploy and run other software services or applications, including operating systems and applications. The consumer does not control or manage the underlying cloud infrastructure but has control over operating systems, deployed applications, storage, and possibly limited control of select networking components such as host firewalls.

 Reference: custom software development company India

Virtualization

Virtualization is base technology of cloud computing. Following video explains what is virtualization, types, its objective and various approaches.

Resources:
1. Virtualization - a base technology of cloud computing - Presentation
2. Virtualizatoin - a base technology of cloud computing - Video
3. Custom software development company India

What is Cloud?

Cloud is viewed as future technology. Following video explains what is Cloud technology, its importance and service models.

One can also download this presentation at 

Cloud technology presentation

Cloud Technology Video

Custom software development company India

What is  Cloud?

As defined by the National Institute of Standards and Technology (NIST), “cloud is a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources that can be rapidly provisioned and released with minimal management effort or service provider interaction.” (Microsoft, 2014)

Cloud computing is a pay-per-usage model. Cloud overcomes the traditional IT bottlenecks like the rooms full of data storage, firewalls and routers along with the teams to support it, when there were needs to invest in upgrades and rebills.

Figure 1 - Cloud computing (computing, 2014)

Deployment Models

History reveals a similar shift happened at the way business used power at the turn of the century. Business no longer has to build, buy or manage costly computing facility on site. Just as business learnt that power provided by a specialized power company improved reliable quality, cloud computing has proven to be more reliable, more secure, more scalable and ultimately more affordable than traditional onsite IT. This is why most new business apps and softwares are now deployed on cloud. Custom software companies in India has also started recommending cloud.

The following deployment models present a number of trade-offs in how customers can control their resources, and the scale, cost, and availability of resources.

1.      Private cloud: The cloud infrastructure is operated solely for an organization. It may be managed by the organization or a third party and may exist on premise or off premise.

2.      Community cloud: The cloud infrastructure is shared by several organizations and supports a specific community that has shared concerns (e.g., mission, security requirements, policy, and compliance considerations). It may be managed by the organizations or a third party and may exist on premise or off premise.

3.      Public cloud: The cloud infrastructure is made available to the general public or a large industry group and is owned by an organization selling cloud services.

4.      Hybrid cloud: The cloud infrastructure is a composition of two or more clouds (private, community, or public) that remain unique entities but that are bound together by standardized or proprietary technology enabling data and application portability.

5.      On-site private cloud: The security perimeter for this deployment model extends around both the subscriber's on-site resources and the private cloud's resources. The private cloud may be centralized at a single subscriber site or may be distributed over several subscriber sites. The subscriber implements the security perimeter, which will not guarantee control over the private cloud's resources, but will enable the subscriber to exercise control over resources entrusted to the on-site private cloud.

Cloud computing challenges

One can easily understand from previous discussion that it’s very beneficial for a company to adopt any of the ACT as per requirement. However it has been witnessed that majority of software companies in India have developed some kind of resistance in adopting the same in their work environment. This is more prevalent in small scaled industries. The resistance is because of following challenges/issues levied by ACT.

Challenges faced by ACT:

1.      Security Issues:
By any chance if intruder get access of cloud’s server or find vulnerability of cluster and start attacking them, it’s very difficult for small scaled organizations to take real-time steps against those attacks due to lack of sufficient funds, unavailability of trained human resources or Information security experts to fight against those.

2.      Data theft or misuse of data:
Data and information is the most important asset for all kind of industries. In spite of existence of strict policies and frameworks, companies find it very difficult to put confidential data in the hands of others. There are possibilities of data being misused by the hosting or cloud companies.

3.      Availability:
Cloud requires the availability of internet connectivity for the services to work. Good and reliable internet connectivity is not available in majority of countries. This puts restriction on various companies to use cloud for their daily operations and activities.

4.      Reliability

Reliability of cloud services heavily depends on good and reliable internet connectivity.

Security, downtime, poor network or connectivity etc. are very common issues facing by internet connectivity esp. in developing countries. So, it’s very hard for any company to just rely on cloud services

On top of above challenges, following are few other reasons that is hindering the acceptance of cloud and ACT.

1.    Lack of information – many companies does not have information or knowledge about what and how cloud computing or ACT can help them to perform better. This is more prevalent in small scaled industries due to lack of skilled manpower and information sources.

2.      Myths – companies have developed certain myths and wrong assumptions about this technology. Few of them are real challenges however many are just myths developed due to low quality information.

Cloud Technology - A Future Technology

20^th century- the age of Information technology changed the whole way of life from living to eating, travelling to communicating and working to enjoying. This new technology also introduced additional challenges like security, confidentiality, privacy and data management issues. As per (EMC, 2014) size of digital data is increasing with the rate more than 50%. This implies that the total size of digital data will be doubled every two years and this rate is increasing constantly. As per press release of Gartner - (Gartner, 2014) , one third of personal data will be on web by 2016. Current technology would not be able to cope up with this and it would be a great challenge to manage this big chunk of data. Security and privacy of data would be another major concern.

To address these challenges, there is introduction of new technology – Advanced Computer Technologies. 21^st century will be the age of Advanced Computer Technologies which is also very well-known by abbreviation ACT.

ACT is categorized into four major components.

• Cloud Computing India
• Cluster Computing
• Distributed Computing
• Grid Computing

i)       Cloud Computing

Cloud computing has been seen as the next revolution of IT and the most famous ACT category. It will radically change the way of working. Cloud computing has a great influence on all kinds of enterprises.

Cloud is a large pool of easily usable and accessible virtualized resources which could be hardware, development platforms and/or services. According to that one can divide cloud into four types: NaaS cloud (Network as a Service), SaaS (Software as a Service) cloud, PaaS (Platform as a Service) cloud and IaaS (Infrastructure as a Service) cloud. All of these can be reconfigured to adjust to a variable load dynamically, allowing also for optimum resource utilization. And, these resources are typically exploited by a pay-per-use model in which guarantees are offered by the Infrastructure Provider by means of customized Service-Level Agreements.

In developed country like USA, Canada, etc. many small scaled companies has started using Cloud technology for various departments. They received following benefits because of implementation of cloud technology.

1. Very high cost reduction
2. Less monitoring and maintenance of IT infrastructure
3. Higher scalability and flexibility

ii)    Cluster Computing

A computer cluster consists of a set of loosely connected or tightly connected computers that work together so that in many respects they can be viewed as a single system. The components of a cluster are usually connected to each other through fast local area networks ("LAN"), with each node (computer used as a server) running its own instance of an operating system. Computer clusters emerged as a result of convergence of a number of computing trends including the availability of low cost microprocessors, high speed networks, and software for high performance distributed computing.

iii)  Distributed Computing

(wikipedia, 2014) Defines distributed computing as a field of computer science that studies distributed systems. A distributed system is a software system in which components located on networked computers communicate and coordinate their actions by passing messages. The components interact with each other in order to achieve a common goal. Three significant characteristics of distributed systems are: concurrency of components, lack of a global clock, and independent failure of components. Examples of distributed systems vary from SOA-based systems to massively multiplayer online games to peer-to-peer applications. A computer program that runs in a distributed system is called a distributed program, and distributed programming is the process of writing such programs. An important goal and challenge of distributed systems is location transparency.

iv)  Grid Computing

As per (Gridcafe, 2014) Grid computing is the collection of computer resources from multiple locations to reach a common goal. The grid can be thought of as a distributed system with non-interactive workloads that involve a large number of files. What distinguishes grid computing from conventional high performance computing systems such as cluster computing is that grids tend to be more loosely coupled, heterogeneous, and geographically dispersed. Although a single grid can be dedicated to a particular application, commonly a grid is used for a variety of purposes. Grids are often constructed with general-purpose grid middleware software libraries.

Grid size varies a considerable amount. Grids are a form of distributed computing whereby a “super virtual computer” is composed of many networked loosely coupled computers acting together to perform large tasks. For certain applications, “distributed” or “grid” computing, can be seen as a special type of parallel computing that relies on complete computers (with onboard CPUs, storage, power supplies, network interfaces, etc.) connected to a network (private, public or the Internet) by a conventional network interface, such as Ethernet. This is in contrast to the traditional notion of a supercomputer, which has many processors connected by a local high-speed computer bus.