Cloud computing is one of the fastest growing trends in the Information Technology (IT) world. It is a simple concept in which shared resources, including software and applications, are consumed by organizations on-demand from a cloud-based service provider. They are paid for according to consumption in much the same way as water or electricity is bought from a public utility company.
Cloud computing owes much of its existence to ‘virtualization technology’ which is essentially a software layer that facilitates the creation of a virtual environment (rather than an actual one) in which hardware and software systems are ‘simulated’. This cuts costs in terms of capital expenditure, power utilisation and space requirements for end users.
The concept was born back in the mainframe era of the 1970s. Then it allowed administrators to consolidate hardware and maximize costly processing power by drawing it from disparate sites, managing and using it as if it were centrally located.
According to South African-born Antonio Piraino, vice president and research director at Tier1 Research (www.t1r.com), more than 70% of enterprises currently use server virtualization technology to reduce costs and increase agility.
Server virtualization is the ‘masking’ of individual file server resources, freeing users from the physical constraints associated with their identification and location, while opening the door to resource sharing, resource optimisation and easy resource expansion or reduction, as required to meet fluctuating processing demand.
To the user, there is no difference between a virtual server and a physical server – except that the virtual server will not be installed at any particular site.
Significantly, it is possible through virtualization, for a single physical server (running hypervisor software) to be able to contain almost any number of virtual machines, bringing a range benefits, including improved total bandwidth, to the users.
Other server virtualization benefits include:
• The ability to consolidate workloads running on multiple physical servers onto a larger physical server comprising multiple independent virtual servers each hosting its own guest operating system and application stack.
• The capability to move applications from one server to another – either virtual or physical – and rapidly provision them.
Hypervisor software is an important element of virtualization. It allows multiple operating systems, including multiple instances of the same operating system, to share hardware resources.
A basic hypervisor was introduced by IBM in the ‘70s which allowed its System 370 processors to share central processing units (CPUs) and direct access storage devices and memory.
What role do virtual servers play ‘in the cloud’? In order for the cloud model, which mandates the supply of on-demand resources to users as services provided by third party organizations (service providers) to be effective it must make use of shared resources and applications.
As a result, the automation capabilities and the economies of scale offered by virtual servers are vital. The unthinkable alternative would be the manual provision of services on a per-client basis using dedicated hardware.
The cloud model must also cater for fluctuations in capacity and other challenges linked to dealing with an amorphous infrastructure. Only through virtualization techniques can these objectives be realised.
Cloud computing and virtualization technologies are committed to work hand-in-hand to deliver a common value proposition: the most cost effective means of improving agility to meet the changing business needs of large and small companies.
If there is an impediment to the long term success of this union it comes in the form of security risks which will be more prevalent in poorly managed environments, where the privacy of data held on virtualized, communal systems often in off-shore repositories, is a concern.
Nevertheless, the cloud and professional service providers have the potential to provide better overall security than is common to most traditional, physical computer systems. This is because security is actually enhanced when data is distributed over a wider base, multiple sites and a large number of devices.
More significantly, cloud computing professionals and their companies generally devote more of their resources – time, effort and money – to identify security challenges and rapidly resolve them than most end-user organisations for whom security is not a core business activity.