an introduction to cloud servers & their benefits

7/30/2019 An Introduction to Cloud Servers & Their Benefits

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An Introduction to Cloud Servers & Their Benefits

Part 1: Definitions

The concept of cloud computing appears omnipresent in our modern world as we rely on on-demand

computing to manage our digital lives across multiple devices - mobiles, tablets, laptops - whilst at home, in the

office or on the move. This trio of articles introduces the key component in cloud computing, the servers that

underpin each service and provide the computing resource, as well as describing how they provide some of

cloud computing's most notable benefits.

Definitions

Cloud Servers:As mentioned above, can be defined as the servers that are used to provide computing

resource for cloud computing. In essence they are servers which are networked together to provide a single

pool of computing power which cloud based services can draw resource from.

Cloud Computing: Describes any computing service whereby computing power is provided as a on-demandservice via a public network - usually the internet. Broadly cloud services can be categorised using the three

following models:

IaaS Infrastructure as a Service:

Pooled physical cloud server and networking resource (without any software platforms). Instead

of the user being provided with a single distinct physical server, multiples thereof or shares

therein, they are provided with the equivalent resources - disk space, RAM, processing power,

bandwidth - drawn from the underlying collective cloud servers. These IaaS platforms can then

be configured and used to install the software, frameworks, firmware etc (e.g., solution stacks)

needed to provide IT services and build software applications.

PaaS Platform as a Service: Virtualised software platforms using pooled cloud servers and network resource. These

services offer the collective physical resources of IaaS together with the above-mentioned

software bundles so that the user has a preconfigured platform on which they can build their IT

applications.

SaaS Software as a Service:

Cloud based applications provided using pooled computing resource. This is the most familiar

incarnation of cloud computing for most members of the public as it includes any application -

such as web based email, cloud storage, online gaming - provided as a service. The

applications are built and run in the cloud with end users accessing them via the internet, often

without any software downloads necessary.

Stuart Mitchell 2013 Page 1 of 4
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How Cloud Servers work

Traditional computing infrastructure models tend to revolve around the idea of single server being used for a

particular IT function (e.g., hosting, software applications etc), whether it be that that server is a dedicated

server - i.e., for the sole use of that client - or shared across multiple clients. Shared servers may have used

the one software/platform installation for all of their IT functions/clients or they may have delivered Virtual

Private Servers (VPS) where each client has distinct operating environment which they can configure.

Cloud computing can deliver similar virtualised server environments but they use resource drawn from not one,

but a multitude of individual physical cloud servers which are networked together to provide combined pool of

server resource. In a sense, it uses a platform that could be considered as a form of clustered hosting whereby

the resource demands of an individual clients IT functions are spread across numerous distinct servers.

However, with cloud hosting the resource pool has enough capacity, with sufficient servers, to provide resource

which multiple clients can tap into as they need to.

Within the infrastructure of cloud services, cloud servers are networked with what are called hypervisors which

are responsible for managing the resource allocation of each cloud server. In other words they control how

much resource is pulled from each underlying cloud server when demands are made of the pool of servers, as

well as managing the virtualised operating environments which utilise this resource.

Part 2: Scalability & Reliability

Having, in the first part of this article, described what cloud servers are and how they work within the context of

cloud computing, the following instalments go on to discuss how they generated some of the key features that

drive the adoption of the cloud at both a personal and enterprise level. This instalment covers the two

performance related benefits ofscalability and reliability.

Scalability

By combining the computing power of a significant number of cloud servers, cloud providers can offer serviceswhich are massively scalable and have no limiting capacities. With hypervisors pulling resource from the

plethora of underlying servers as and when needed, cloud services can be responsive to demand so that

increased requests from a clients particular cloud service can be met instantaneously with the computing

power that it needs. There is no issue with functions being limited by the capacity of one server and therefore

clients having to acquire and configure additional servers when there are rises in demand. Whats more, with

cloud services, where the product has already be provisioned, the client can simply tap into the service without

the costs and delays of the initial server set up that would otherwise be incurred.

For those clients whose IT functions are susceptible to large fluctuations in use, for example websites with

varying traffic levels, pooled cloud server resource removes the chance of service failure when there are spikesin demand. Additionally, on the flip side, it removes the need to invest in high capacity setups - as contingency

for these spikes - which would go unused for a large proportion of time. Indeed, if the clients demands fall, the

resource they use (and pay for) can also reduce accordingly.

Reliability - Redundancy & Uptime

As mentioned the high number of cloud servers used to form a cloud service offering means that services are

less likely to be disrupted with performance issues or downtime due to spikes in demand. However, the model

also protects against single points of failure. If one server goes offline it wont disrupt the service to which it was

contributing resource because there are plenty other servers to seamlessly provide that resource in its place. In

some cases, the physical servers are located across different data centres and even different countries so thatthere could conceivably be an extreme failure causing a data centre to go offline without the cloud service being

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disrupted. In some models, back ups are specifically created in different data centres to combat this risk.

In addition to unforeseen failures, pooled server resource can also allow maintenance - for example, patching

of operating systems - to be carried out on the servers and networks without any disruption or downtime for the

cloud service. Whats more, that maintenance, as well as any other supporting activities optimising the

performance, security and stability of the cloud servers will be performed by staff with the relevant expertise

working for either the cloud service provider or the hosting provider. In other words, the end user has no need to

invest in acquiring that expertise themselves and can instead focus on the performance of the end product.

Part 3: Cost & Deployment

The final instalment of this trio of articles looks at the features of the two cloud server deployment models,

public and private, as well as discussing how they can deliver real cost savings to their customers.

Cost Efficiencies

As mentioned previously, the responsive scalability of pooled cloud servers means that cloud services can

offer significant cost efficiencies for the end user - the most salient of which is that the client need only pay for

what they use. Without being bound by the fixed physical capacities of single servers, clients are not required to

pay up front for capacity which they may not make use of, whether it be their initial outlay or subsequent steps

up to cater for increases in demand. In addition, they avoid the set up costs which would otherwise be incurred

by bringing individual servers online. Instead any set up costs generated when the underlying cloud servers

were brought online are overheads for the cloud provider and are diluted by economies of scale before having

any impact on their pricing model. This is particularly the case as many cloud services minimise the effort and

expense of specific cloud server and platform configurations by offering standardised services into which theclient taps.

Lastly, cloud models allow providers to do away with long term lock-ins. Without the longer term overheads of

bringing individual servers online for individual clients and maintaining them there isnt the dependency on those

clients for a return on that investment from the providers point of view.

Deployment

There are two common deployment models for cloud services which span the service level models (IaaS,

PaaS, SaaS) described in part one: Public Cloud:and Private Cloud.

Perhaps the most familiar to general population, and also the most likely to deliver some of the features and

benefits mentioned previously, is the typical public cloud model. This model utilises the large number of pooled

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cloud servers located in data centers, to provide a service over the internet which members of the public can

sign up for and access. However, the exact level of resource - and therefore capacity, scalability and

redundancy - underpinning the each public cloud service will depend on each provider. The underlying

infrastructure, including servers, will be shared across all of the services end users whilst the points at which

the service can be accessed are open to anyone, anywhere, on any device as long as they have an internet

connection. Consequently, one of the models key strengths, its accessibility, leads to its most prominent

weakness, security.

Services which need to implement higher levels of security can instead use private cloud models. The

architecture of private clouds can vary but they are defined by the fact that the cloud is ring-fenced for the use

of one client. Servers can either be located in a data center, and accessed via leased lines or trusted provider

networks, or on the clients premises, and accessed by secure local network connections. They can be

provisioned as either physical or virtual servers, but theyll never be shared across multiple clients. Access to

the servers and the cloud service will always be behind the clients firewall to ensure that only trusted users can

even attempt to use it.

Private clouds, therefore, offer greater levels of security (depending on the exact set up), but utilising smaller

pools of servers means that they cannot always match the economies of scale, high capacities, redundancy

and responsive scalability of public cloud models. Although, these qualities can still be achieved more readily

than more traditional fixed capacity server configurations on local or trusted networks.

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an introduction to cloud servers & their benefits

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