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Introduction to Cloud Computing and Technologies

Par Gaurav REESAUL Publié le 13/08/2017 à 00:29:01 Noter cet article:
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Previously, the word Cloud was used as a figure of speech for Internet. Afterwards, it was used to portray the Internet in computer network diagrams. To find out more about the origin of the Cloud, the details can be looked into as provided on Wikipedia.

Cloud Computing can be denoted as the distribution of resources on the Cloud. According to NIST (National Institute of Standard and Technology), the formal definition of Cloud Computing is the following:

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.

Cloud computing is a type of computing that relies on distributing computing resources instead of having local servers or personal devices to handle applications. In cloud computing, the word cloud (also expressed as "the cloud") is used as a metaphor for "the Internet," so the phrase cloud computing means "a type of Internet-based computing," where diverse services — such as servers, storage and applications —are delivered to an organization's computers and devices through the Internet.

In the most-simple explanation, taking services ("cloud services") and moving them outside an organizations firewall on shared systems is called cloud computing. Rather than accessing applications and services via Web, it can easily be accessed through the hard drive. The services are supplied and used over the Internet and are paid for by cloud customer, typically on an "as-needed, pay-per-use" business model. The cloud provider maintains the cloud infrastructure, rather than the individual cloud customer. Cloud computing is equivalent to grid computing, a type of computing where, in order, to solve problems which are too intensive for any stand-alone machine, unused processing cycles of all computers in a network are harnessed.

Built on top of basic provisioning and releasing of resources, different kinds of services are offered by Cloud Computing providers. Most of these services fall into one of the following categories:

Infrastructure as a Service (IaaS)

Infrastructure as a Service (IaaS) is a form of Cloud Computing which offers on-demand physical and virtual computing resources, storage, network, firewall, load balancers, etc. IaaS uses some form of Hypervisor, like Xen, KVM, VMware ESX/ESXi, Hyper-V, to provide virtual computing resources. Infrastructure as a Service is the mainstay of all cloud services, offering the compute resources. After getting the compute resources, other services are provided on top of that. Example: Let's say that you want to have a set of 10 Linux systems with 4GB RAM each, and two Windows systems with 8GB each to deploy your software. You can go to any of the IaaS providers and request these systems. Generally, a IaaS provider creates the respective VMs in the background, puts them in the same internal network, and shares the credentials with you, thus allowing you to access them. Other than VMs, some IaaS providers offer bare-metal machines for provisioning.

Platform as a Service (PaaS)

Platform as a service (PaaS) or application platform as a service (aPaaS) is a category of cloud computing services that offers a platform allowing customers to develop, run, and manage applications without the complexity of building and maintaining the infrastructure typically associated with developing and launching an app.

Software as a Service (SaaS)

Software as a service (SaaS) is a software distribution model in which a third-party provider hosts application and makes them available to customers over the Internet.Most providers use some form of web interface, on top of which the desired stack can be built. Cloud Providers use a pay-as-you-go model, in which the resources, used in a given duration are paid for.

Key Features of Cloud Computing

Cloud Computing provides key features such as:

• Speed and Agility

The required resources are just one click away, which saves time and provides agility and can also easily scale up or down, depending on our need.

A key benefit often discussed about cloud computing is agility is enabled. This benefit is real and powerful. However, the term agility is used to define two different kinds of benefit; both are real, but one of them will, eventually, be viewed as offering the greatest impact.

It is tied to the rapid provisioning of computer resources. New compute commands or storage in minutes can generally be provided with cloud environments, a far cry from the very regular weeks (or months, in some organizations) the same provisioning process can take in typical IT shops.

As one could envision, work is able to begin much more quickly the dramatic shortening of the provisioning timeframe. No more submitting a request for computing resources and then anxiously watching e-mail for a fulfillment response.

• Cost

It reduces the up-front cost to setup the infrastructure and allows better focus on applications and business. Cloud providers have features to estimate the cost, which allows better planning. There are 3 main cost centers when dealing with cloud, and they are:

Network: Cost per Rack Unit

The expenses are determined by cloud providers when setting the price to maintaining the network. Costs for network hardware, network infrastructure maintenance, and labor are calculated at first. Afterwards these expenses are added together and then divided by the number of rack units a business will need for its IaaS cloud. Some of the factors that go into these costs comprise of:

Network hardware costs: Each virtual server requires the provider to capitalize in certain types of network hardware. The hardware is bought and the cost over each device’s life cycle is depreciated.

Network infrastructure maintenance: These costs include security tools, such as firewalls, LAN switching, patch panels, load balancers, routing and uplinks – all the infrastructure that keeps the network running smoothly.

Labor: Cost for staff to maintain, manage, monitor and troubleshoot cloud computing infrastructure. The staff should be available 24×7 to ensure uptime and availability of the cloud environment.

Compute: Cost per GB of Virtual RAM

Each organization has an exclusive set of requirements including use of CPU. Most providers calculate the cost of CPU by determining the respective company’s cost per GB of virtual RAM, which includes:

Hardware operation: the total amount of virtual RAM deployed in the public clouds is looked at and then that is divided into the cost per rack unit of the hardware by the providers. The costs may include licensing and usage-based subscription costs, depending on the virtual operating system.

Hardware acquisition: This computation informs the provider of the costs required to acquire hardware for each GB of virtual RAM that they will be using. They also depreciate these costs over the hardware life cycle.

Storage: Cost per GB of Virtual Disk

Storage costs are like the compute costs. The provider calculates how much it costs to operate the storage hardware and acquire new hardware for the storage needs.

Shared Costs

The individual cloud computing infrastructure costs are not all that go into the price quote. Like IaaS cloud users, the quote includes a share of what it costs to power and cool the underlying infrastructure for the IaaS platform in the datacenter. The price quote may also include charges related to software licenses, hosting, support and other service components. What makes IaaS so cost-effective is sharing these costs with other organizations in the public cloud.

Easy access to resources: The infrastructure can be accessed from any place and device by all the users, as long as they remain connected to the provider.

Maintenance: All the maintenance work for the resources is done by the provider. Hence, end-users do not have to worry about this aspect.

Multi-tenancy: The same pool of resources can be used by multiple users. A multi-tenant cloud is a cloud computing architecture that allows users to share computing resources in a public or private cloud. The data of each tenant is isolated and remains invisible to other tenants. This in many ways ensures that the data are secure from user to user and ensure maximum use of the resources.

Reliability: Resources can be hosted in different datacenter locations, to provide increased reliability. Cloud computing can be as secure, if not more secure, than the traditional environment. The ability to protect data in transit by encrypting it in the pipe between Google and the user's desktop, as well as offer control over who can access the data is offered by services like Google Apps Premier.

Cloud Deployment Models

Generally, a Cloud is deployed in the following models:

• Private Cloud

Private clouds will provide computing power as a service within a virtualized environment using an underlying pool of physical computing resource which is similar to other cloud models. However, under the private cloud model, the pool of resource of the cloud is only accessible by a single organization, therefore providing that organization with greater control and privacy.

A private cloud is designed to offer the same features and benefits of public cloud systems, but takes off a number of objections to the cloud computing model including control over enterprise and customer data, worries about security, and issues connected to regulatory compliance.

It is selected and operated solely for one organization. It can be hosted internally or externally and managed by internal teams or a third party. A private cloud can be built using a software stack like OpenStack.

• Public Cloud

Public clouds are among the most familiar form of cloud technology, allowing consumers to employ a virtual environment through a series of shared servers that are openly accessible over a public network. With a public cloud, the files can be stored remotely and securely, and then later access them for future use on a different computer.

A wide range of services is offered by the public cloud to multiple clients while still utilizing a shared infrastructure. Many different business models exist in which this form of service is offered.Software as a service (SaaS) is a popular application, providing consumers access to software and online storage via remote servers. Infrastructure as a service (IaaS) and even platform as a service (PaaS) give users access to cloud-based web hosting and development environments.

Each of these caters to a public cloud method of resource sharing, though many are technically considered private clouds due to monthly service fees. Public clouds do not often offer the same level of security and infrastructure as private clouds, appropriate to the level of service offered.

It is open to the public and can be used after swiping the credit card. AWS and Google Compute Engine are examples of Public Clouds.

• Hybrid Cloud

Public and Private Clouds are trussed together to offer the Hybrid Cloud.

Among other things, a Hybrid Cloud can be used to:

- Store sensitive information on a Private Cloud, while offering public services based on the information from a Public Cloud.

Security involving Cloud Computing

To a great extent, small businesses are moving to cloud computing, signing up with private providers that make sophisticated applications more affordable as well as setting up their own accounts with public social media sites like Facebook.

Private and public clouds function in a similar way: Applications are hosted on a server and accessed over the Internet. Whether a Software as a Service (SaaS) version of customer relationship management (CRM) software is used, offsite backups of the company data is created, or a social media marketing page is set up, the third-party company can be trusted with information about the business and, most likely, the customers.

Although cloud computing can offer small businesses significant cost-saving benefits—namely, the pay-as-you-go access to sophisticated software and powerful hardware—it does not mean that the service does not come with certain security risks. When evaluating potential providers of cloud-based services, you should keep these top five security concerns in mind.

1. Secure data transfer

All the traffic travelling between the network and whatever service that is accessed in the cloud must traverse the Internet. Users must make sure their data is always travelling on a secure channel; to only connect their browser to the provider via a URL that begins with ”https.” Also, the data should always be encrypted and authenticated using industry standard protocols, such as IPsec (Internet Protocol Security), that have been developed specifically for protecting Internet traffic.

2. Secure software interfaces

The Cloud Security Alliance (CSA) recommends that users be aware of the software interfaces, or APIs, that are used to interact with cloud services. ”Reliance on a weak set of interfaces and APIs exposes organizations to a variety of security issues related to confidentiality, integrity, availability, and accountability,” says the group in its Top Threats to Cloud Computing document. CSA recommends learning how any cloud provider you are considering integrates security throughout its service, from authentication and access control techniques to activity monitoring policies.

3. Secure stored data

The data should be securely encrypted when it is on the provider's servers and while it is in use by the cloud service. In Q&A: Demystifying Cloud Security, Forrester warns that few cloud providers assure protection for data being used within the application or for disposing of your data. Users should ask potential cloud providers how they secure their data not only when it is in transit but also when it is on their servers and accessed by the cloud-based applications and to find out, too, if the providers securely dispose of their data, for example, by deleting the encryption key.

4. User access control

Data stored on a cloud provider's server can potentially be accessed by an employee of that company, and users of the cloud services have none of the usual personnel controls over those people. The sensitivity of the data that are allowed out into the cloud should be carefully considered. Afterwards users should ask the providers for specifics about the people who manage their data and the level of access they have to it.

5. Data separation

Every cloud-based service shares resources, namely space on the provider's servers and other parts of the provider's infrastructure. Hypervisor software is used to create virtual containers on the provider's hardware for each of its customers. But CSA notes that ”attacks have surfaced in recent years that target the shared technology inside Cloud Computing environments.” Therefore compartmentalization techniques should be investigated, such as data encryption, the provider uses to prevent access into their virtual container by other customers.

Advantages of Cloud Computing

1. Drive down costs

Large capital expenditure on hardware and upgrades are avoided. Cloud can also enhance cost efficiency by more closely matching the cost pattern to the revenue/demand pattern, moving a business from a capital-intensive cost model to an Opex model.

2. Cope with demand

Infrastructure needed nowadays is known, but not those required in the future. As the growth of a business increases, a cloud environment should also grow. And when demand is unpredictable or testing of a new application is required, users have the ability spin capacity up or down, while paying only for what they use.

3. Run your business, don't worry about your infrastructure

Monitoring the infrastructure 24/7 is time consuming and expensive when having a business to run. A managed cloud solution means that the hosting provider is managing instead of the cloud consumer. In addition to monitoring the infrastructure and keeping the data safe, they can provide creative and practical solutions to the consumers’ needs, as well as expert advice to keep the IT infrastructure working efficiently as the needs evolve.

4. Innovate and lead

Ever-evolving business requirements mean that the IT infrastructure has to be flexible. With a cloud infrastructure, you can rapidly deploy new projects and take them live quickly, keeping you at the vanguard of innovation in your sector.

5. Improved security and compliance

Protecting the business against loss of revenue and brand damage is mandatory. In addition, many organizations face strict supervisory and compliance obligations. A cloud environment means that this responsibility no longer rests entirely on the consumers’ shoulders. The cloud hosting provider will build in resiliency and agility at an infrastructure-level to diminish the risk of a security breach, and will work to help address compliance and regulatory requirements.

6. Reduce your carbon footprint

Hosting in a data center rather than on-site gives the take advantage of the modern energy-efficient technology. Furthermore, as cloud service providers host multiple customers on shared infrastructure, they can drive higher and more efficient utilization of energy resources.

7. Future-proof your business

There is unprecedented demand for access to data anywhere, any time and on any device. By adopting the cloud, emerging mobile can be handled, BYOD and wearable technology trends.

The 5 main disadvantages of Cloud Computing

1. Downtime

This may be one of the worst disadvantages of cloud computing. No cloud provider, not even the very best, would assert immunity to service outages. Cloud computing systems are internet based, which means the access is fully dependent on the Internet connection. And, like any hardware, cloud platforms can sometimes fail for any one of a thousand reasons.

2. Security and Privacy

When it comes to managing sensitive data, issues concerning security and privacy must not be left out. We must not forget Code Space and what happened to it after its AWS EC2 console was hacked and its data eventually deleted, forcing the company to close doors forever. By leveraging a remote cloud based infrastructure, a company basically outsource everything it has. The cloud service provider is expected to manage and safeguard the fundamental hardware infrastructure of a deployment, however remote access is the responsibility of the consumer and, in any case, no system is perfectly secure. All the risk scenarios should carefully ponder upon.

3. Vulnerability to attack

In cloud computing, every section is possibly accessible from the Internet. As always, nothing connected to the Internet is perfectly secure and even the best teams suffer severe attacks and security breaches. But since cloud computing is open to the public it makes it easier for people with no knowledge about computers or servers to use the cloud . No one at AWS checks your administration skills before granting you an account: all it takes to get started is a valid credit card.

4. Cloud Computing platform dependencies

Absolute dependency, also known as “vendor lock-in” is another of the disadvantages of cloud computing. Inherent differences between vendor systems can sometimes make it impossible to migrate from one cloud platform to another. As much as it can be complex and expensive to reconfigure the applications so as to meet the requirements of a new host, migration could also disclose the data to additional security and privacy vulnerabilities.


This document shows a bit of an overview on cloud computing. It also depicts the security around the cloud. For start-up businesses, the cloud offers an essential differentiator. For the first time, anyone with an idea can start a business and get it up and running quickly an enterprise-grade IT infrastructure that is flexible enough to accommodate growth, yet requires minimal up-front capital expenditure.

For small to medium sized businesses that have limited IT resources, the cloud allows the possibility of focusing on running their business rather than their IT. They can take advantage of a wide portfolio of compute, storage and network products, then cost effectively scale on-demand as your business grows — often while delivering faster time to market than previously achievable.

Mid to large enterprises often face complex hosting needs, varying departmental and corporate-wide infrastructure requirements, high traffic websites and demanding applications. For them, the cloud can often drive down costs and deliver increased operational efficiency, productivity, agility and flexibility.

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