An Introduction to Cloud Servers & Their Benefits - 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 the client 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 isn’t the dependency on those clients for a return on that investment from the provider’s 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 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 service’s 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 model’s 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 client’s premises, and accessed by secure local network connections. They can be provisioned as either physical or virtual servers, but they’ll never be shared across multiple clients. Access to the servers and the cloud service will always be behind the client’s 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 - 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 of scalability and reliability.

Scalability
By combining the computing power of a significant number of cloud servers, cloud providers can offer services which 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 client’s 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. What’s 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 spikes in 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 client’s 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 won’t 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 that there could conceivably be an extreme failure causing a data centre to go offline without the cloud service being 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. What’s 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.

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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-demand service 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.

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 client’s 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.

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Alternative Cloud Models

In the previous instalment of this article, the two fundamental models of cloud computing, private and public clouds, were described. The following installment introduces two further variations on these models which can be used to add flexibility to an organisation’s IT infrastructure, the hybrid and the community cloud models.

Community Cloud
A community cloud model describes a scenario in which a number of organisations with similar IT demands club together to use the same cloud infrastructure. They are particularly appropriate where the organisations perform similar functions and therefore require the same configurations, especially in relation to security and compliance. In essence it is a half-way house between the private and public cloud models.

The model is similar to that of a private cloud in that it is a ring fenced platform which ensures greater levels of security than the public cloud offers and it can also be hosted internally by the constituent organisations to ensure greater ownership and control (at the expense of some cost savings). However, because it has multiple clients (usually a small number) it also provides economies of scale which are missing in private clouds and therefore greater cost savings than the individual equivalents. Furthermore, in common with a public cloud model, organisations can take advantage of pay as you go pricing structures.

Hybrid Cloud
The hybrid model of cloud computing is also somewhat self explanatory in that it is used to describe any configuration which utilises a combination of the public and private cloud computing models, or indeed a combination involving community cloud models. It comes under the slightly broader categorisation of hybrid IT - that is an IT platform which integrates a mixture of internal and external networks and services so that the resource being used can provide the maximum benefit for each business function.

Hybrid cloud models can therefore give an organisation access to the differing benefits of public and private models, primarily cost/scalability and security respectively, as and when they need them by integrating the different models for the different functions within the organisation. For example, a business that processes and stores sensitive data may do so on a private cloud platform to ensure that it is secure whilst also taking advantage of the scalability of a virtualised environment. It may then use integrated public cloud services for all of the less sensitive functions, such as project planning, in order to benefit from the considerable costs savings and scalability that that can bring.

A hybrid cloud set-up, like hybrid cloud hosting, can be constructed in a couple of ways: either by providers of each model of cloud computing teaming up to provide a hybrid platform which organisations can sign up to to perform their differing IT functions; or by an organisation managing their own internal private cloud or other IT infrastructure and then signing up to an integrated external public cloud service where they can, to handle their non data sensitive functions.

Whatever a client’s computing needs, there will be a cloud based service to meet their demand and provide that client with the benefits of virtualisation and utility style computing; including responsive on-demand scalability, cost efficiencies (including pay as you go and free services) and redundancy. By becoming aware of the potential of using public, private and community clouds as well as the hybrid models which combine and maximise the benefits of each, organisations can ensure that they keep their IT operations as efficient, productive and secure as possible.
© Stuart Mitchell 2012

Public vs Private Clouds

As an alternative to the three tiered classification of cloud based services - Infrastructure as a Service (IaaS), Platform as a Service (PaaS) and Software as a Sevice (SaaS) - cloud computing can also be classified based upon how the underlying networks are implemented and accessed by the client. The following article provides and overview of the two principle models Public and Private Clouds.

These models do not describe strict architectures and so a variety of configurations can be employed to achieve each model of cloud computing. Furthermore, each model can be used to offer each tier of cloud service as mentioned above.

Public Cloud
When most people think of cloud computing they think of a typical public cloud model where the services on offer are available to public customers through a public network, usually the internet. The accessibility of this model allows for cloud services to be supplied to a mass market and for the provider to centralise/pool (and share) the physical computing resource they require to offer the services; utilising virtualisation where they need to establish operating environments. As a result, consumers and providers of public cloud services can benefit from considerable economies of scale to reduce their costs as well as sheer scalability to respond to fluctuations in demand.

Public cloud services can often be free to the consumer, funded for example by advertising, however where a charge is applied they usually follow a pay as you go (PAYG) type model - that is the consumer is supplied with the computing resource they need as and when they need it and are only charged for what they use. Many of the cloud services that are most familiar to the general consumer, particularly Software as a Service (SaaS) applications such as Google Docs (cloud based ‘office’ applications), Gmail (web based email) or Dropbox (cloud storage), fall under the public cloud model.

For some consumers, the mechanisms of the public cloud which bring such cost savings and widespread availability can also bring undesired security vulnerabilities. Although the security of these services is always improving, the fact that data is transferred across public networks and stored on shared physical and/or virtual servers may provide obstacles to some clients using the public cloud for processing sensitive data. Instead they might look towards to private cloud services.

Private Cloud
Cloud clients who are handling, processing or storing sensitive data that they need ensure remains private and secure and who want to take advantage of some of the cost, availability and scalability benefits that cloud computing usually offers, can utilise private cloud services as an alternative to the public cloud.

The concept of a private cloud is harder to define than that of public cloud and no strict definition really exists. It is best to categorise private clouds by some of the features that they provide and the issues that they address in comparison to public services, such as data security and ownership control (of servers etc), rather than the mechanisms they use. They will of course also display the tell-tale features of cloud computing in general - virtualisation, instantaneous scalability, PAYG charging and automated allocation of resources on demand.

The entirety of a private cloud will only be accessible by a single organisation (in contrast to multiple clients using services within the public cloud) and some examples therefore also allow the end user organisation to have control over the management of the cloud network and its set-up so that they can tailor it to their own needs. The flip side of this control however is that some of the cost savings generated by the centralised management of public cloud services will be lost in private clouds. Instead the service becomes closer in structure to a traditional local network based service, but with the benefits of virtualisation mentioned above.

The network of servers itself can be hosted internally by the organisation (as required by some regulatory bodies for sensitive data) or externally by a cloud provider (e.g., a Virtual Data Centre, VDC) but access will be restricted to connections made behind the organisation's firewall. To provide the security and control private clouds can employ certain characteristics techniques including closed networks of servers (not shared between clients), hosting of servers on site and leased lines to access these networks where they are hosted off site.

© Stuart Mitchell 2012

The Classifications of Cloud Computing

Although hype and conjecture has surrounded the concept of cloud computing for a long time now it is more than just a buzz term. With the increased uptake in portable devices such as smartphones, tablets and even laptops in the private consumer sector, as well as the resultant shift to home based work, business on the move and the use of personal devices in the workplace, the need for centralised, virtualised computing resources has surged in the last couple of years. In fact many of us use some form of cloud computing every day without really acknowledging it, whether it be webmail or online gaming.

What is Cloud Computing
In a very general sense, cloud computing describes any scenario where the user (the cloud client) is accessing computing resource from a virtualised environment (the cloud) via an internet connection. It can be though of in contrast to use of computing resource on the user’s local machine, local network or defined physical machines on other networks. Cloud services generally work by providers pooling together extensive physical resources (e.g., multiple servers across multiple data centers) to create a service which users can tap into as and when they need it (i.e., on demand) without the need to install anything locally, hardware or software.

Where a service is chargeable they can be offered on a pay as you go basis where the user only pays for what they actually consume, much like a utility like electricity where consumers can tap into the national grid (analogous to the internet) and pay simply for what they use.

There are a variety of different services that can be propositioned under the cloud computing umbrella term and that meet the above definitions, but they are broadly classified into three camps, depending on the provisioning of hardware and software resource.

Infrastructure as a Service (IaaS)
Usually shortened to IaaS, this classification of cloud computing incorporates services which offer virtualised physical computing resource, that is, resource such as server space, bandwidth, networking.

Salient examples of IaaS offerings include cloud hosting where websites are hosted on virtual server partitions which draw physical resource from a pool of multiple servers across multiple data centers. This idea can offer specific advantages such as

cost effective scaleability - hardware resource can be accessed on demand so that the client only pays for what they use and they are not retricted by capacity
reliability - there is no single point of server failure as data is also duplicated (backed up) across multiple servers. If one server fails, the web site will not go offline

The areas of IaaS and cloud hosting can also include the concept of Virtual Data Centers (VDC) where a virtualised network of servers or computers is made available to the user instead of simply server space.

Platform as a Service (PaaS)
PaaS describes a proposition which includes the software that is required to create an operating environment which can be used by the client to create their own applications. In other words PaaS will include tools such as a solution stack - operating system, server-side scripting environment, database support etc - in addition to the pooled computing hardware resource as detailed above. Cloud clients often have control over what tools are installed within their platforms, sometimes from a restricted list, and how they are configured but all the building blocks are supplied by the provider.

Cloud Hosting can again be used as an example of PaaS as many of the packages on the market will provide the user with, not just the virtual server, but the entire platform such as the solution stack that is required to build and host a website. Other examples of PaaS include test and development environments for software builds. As with SaaS below, these services offer their clients greater opportunities for collaboration and location independence when they are being used to build applications.

Software as a Service (SaaS)
This is probably the most familiar form of cloud computing to most consumers. It describes an offering where the service being accessed via the internet is an application or a software service. It is an area that many of the big software and internet companies such as Microsoft, Google and Apple are flourishing in as we all seem to be following the trend, moving away from locally installed (and sometimes incompatible) software to applications that are being run in the cloud, accessed through an internet browser.

Obvious examples of SaaS include Google Docs and Microsoft Office 365 (which can integrate with the traditional installation of the software), but this class of cloud computing also encompasses other services such as webmail and online gaming which are accessed entirely online.

There are a number of cloud computing categories which fall within SaaS and follow the same naming convention such as Desktop as a Service (or Virtual Desktops, where a virtual version of a computer’s desktop is stored and accessed in the cloud) and Test Environment as a Cloud (TEaaS, involving a central hosted test environment for the testing of software).

Key drivers behind the growth in SaaS are the facts that cloud based applications can be used from any physical location as long as there is an internet connection (ADSL or 3G for example) and across any device running any operating system. This independence from geographical and technological constraints allows personal users and workers to not only work on applications and files in any scenario but to collaborate on and share these services with few restrictions.

© Stuart Mitchell 2012

What Is Cloud Hosting?

SOMF Cloud Computing Model (Photo credit: Wikipedia)

IT professionals and private consumers of technology alike will no doubt be aware of the term cloud computing. A term and a concept that appears to be consuming everything in its path as the future of the IT industry. The following article looks at one incarnation of the technology that offers great potential for enterprise, that of cloud hosting.

Cloud Computing
The concept of cloud computing is one that manifests itself in many ways and covers a broad array of applications and functions. In its simplest sense it refers to end users accessing computing resources they need from a cloud, i.e., a shared pool of IT resources from a remote location made available through the internet. Cloud services are characterised by the fact that they do not require data to be stored on, software installed on, or configuration and preferences to be set on end users’ devices. Instead users access resources that are maintained and managed in remote centralised locations by a specialist provider. They are therefore free of physical, geographical and technological constraints and can access the same cloud service wherever they are, across any device - mobile, desktop or tablet - as long as they have an internet connection.

The concept can also be thought of, and indeed referred to, as utility computing. The fact that computing resources, be it hardware or software (see below), are available as a service that can be tapped into on-demand rather than requiring local installations, is akin to a household utility. Indeed, a commonly used analogy is that of electricity. Electricity is generated in a series of centralised locations by specialist providers using advanced equipment and techniques (pooled with wider electricity resources) and accessed through the grid in contrast to a system whereby each consumer builds, installs and maintains their own generator, with each having a finite capacity. In cloud computing the internet is analogous to the electricity grid and the user accesses the computing utility rather than build, install and maintain their own computing resources. Therefore, as with centralised electricity production, it delivers economies of scale for the provider, and consequently cost savings for the user, as well as the ability to access what you need, when you need it; providing solutions that are scalable and responsive to demand.

Generally the end user has no involvement (or need to invest) in the installation and maintenance of the hardware and infrastructure underpinning a cloud service, which is all controlled by the third party provider, but they can have input into software installations and configuration depending on which service they sign up for. These cloud services can be broken down into three tiers:

IaaS - Infrastructure as a Service - offers access to physical computing resource, including disk space on virtual servers and networks whilst leaving the installation and configuration of operating systems and software to the client.
PaaS - Platform as a Service - a platform including physical resource and operating systems together with the software (e.g., a solution stack) required to run a particular computing environment.
SaaS - Software as a Service - the user simply has access to applications running on a cloud platform.

Cloud Hosting
Cloud Hosting is a form of cloud computing, more specifically either IaaS or PaaS, whereby the end user can get access to shared physical resources - servers, networks, bandwidth and supporting infrastructure (plus solution stacks on PaaS) - without the need to purchase, rent or install specific hardware themselves. Typically cloud hosting is employed to serve websites but it can support other enterprise functions and networks.

In essence it is a variant of the wider concept of shared hosting but instead of multiple websites, for example, sharing a single physical server (including a software installation), those multiple sites are hosted across a network of shared servers (and computing resources) managed using software partitions. Cloud Hosting therefore provides scalable on-demand hosting capacity (as the appropriate level of physical resources can be accessed in accordance with demand), where the client doesn’t have to worry about the specifics of hardware installations and need only pay for what they use.

VDC - Under the banner of cloud hosting a VDC, or a Virtual Data Center, is again an IaaS which offers enterprises the opportunity to utilise their own networks of servers from the cloud using servers which are defined by software partitions rather than being physically distinct (although the underlying hardware resource is ultimately located within physical data centers).

Whatever demands a website and a business’s propositions create, there is always a hosting solution to fit the purpose. For many that will be cloud hosting due to its ability to offer cost efficiencies alongside unparalleled flexibility.