‘Virtualisation’ has been growing in popularity, particularly since the end of 2006, as a form of infrastructure technology that can be used to consolidate the hardware resources of a business. But what exactly is it?
Put simply, ‘virtualisation’ means either ‘partitioning’ a single physical resource (such as a server, operating system or application) to make it seem to function as multiple resources or ‘aggregating’ numerous physical resources (such as servers or storage devices) so that they appear to be just one resource. It will appear to end-users or other systems that the physical characteristics of the partitioned or aggregated resources are different from those that they have in reality. Some of the main types of virtualisation are as follows.
Server virtualisation: This type of virtualisation involves a server administrator using a software application to divide one physical server into multiple isolated virtual environments or ‘guests’, each of which can use either different operating systems or multiple instances of the same operating system.
Operating system virtualisation: Operating system virtualisation involves installing different applications in isolated operating system instances. The hardware used is not ‘virtualised’ in the same way that it is in server virtualisation.
Application virtualisation: This form of virtualisation separates applications from the operating system of the machine on which they are used. A virtualised application can be run on a physical machine using its own settings without having to be installed on that machine, avoiding conflicts arising between different applications used on the same machine.
The main benefit obtained from virtualisation is improved efficiency in the use of system resources. Numerous virtual machines can share the same hardware resources, meaning that you can run several operating systems (OS) and applications at the same time on one physical server. You can also provide standardized PC environments (configured only to allow access to certain applications or subject to restrictions on use) as virtual machines for use by employees or customers.
So virtualisation can potentially reduce the outlay of a business on hardware and provide an IT infrastructure that is simpler to control. All this sounds great. So where is the catch?
Virtualisation platforms make it easy to replicate a template virtual machine a large number of times. Within that template will be a guest OS together with any number of software applications. The OS and applications are likely to be licensed to the user (unless the user owns them) and any such licence is likely to contain restrictions on use. For example, if an application that you are using is licensed on a per-computer basis (not allowing for use on more than one virtual machine), you may find that, in order to avoid infringing the software manufacturer’s copyright, you will need to pay licence fees for each virtual machine.
Licence requirements can vary widely. Some allow use of a piece of software on a fixed, or even unlimited, number of virtual machines per physical machine and others permitting the licensee to use the software on all machines used at one location or by one business (eg a site licence). If a licence allows use on only a limited number of virtual machines, you will need to keep track of how many copies of your template virtual machine are made (and therefore how many copies of the software you are using). At present there is no easy way to measure the number of copies of a piece of software that are being used in a virtual environment so users of virtualisation platforms could easily fall into the trap of software copyright infringement. A robust software asset management platform is essential.
An example of a typical single user software licence provision is as follows:
‘You may install and use one copy of the software on a single computer. You may neither use the software on more than one computer at the same time, nor install the software on a server based computer, nor share the licence between different computers (i.e. install part of the software on one machine and different parts on another).’
If you are considering implementing a virtual infrastructure, the potential problems with this type of licence are as follows:
• This licence is limited to use on a single computer. Even if it allowed for use on, say, ten computers and you set up a virtual template machine including that software, you would need to keep a record of how many instances of that virtual machine had been created (to ensure that there were no more than ten).
• As the licence does not permit use on a ‘server based computer’, the relevant software could not be used on a virtual machine (which would be server-based).
• Even if the language above allowed you to install the software on a server, if you did so on a server on which 20 virtual machines are run, you could require a licence for each of those machines (even if you only want to use the software on one of them).
• Furthermore, if you install the software on a four-processor server but only want to use it on two of those processors, you could have to pay a licence for all four processors depending upon whether or not the software licence views the virtualisation software you use as a hardware or software partition.
• If the software is for a package of applications (eg it includes an e-mail application and word processing application), you would not be entitled to install the e-mail application on one machine and the word processor on another.
Some licences also do not allow for a piece of software to be transferred from the central processing unit on which it is first installed to another (even if the software is then removed from the first central processing unit).
A further issue has arisen in relation to licensing of virtual servers. The licensing trend to date has been to grant licences only on a per-processor basis, defining ‘processor’ as up to four cores per processor. Whilst this would mean that only one licence would be required for dual and/or quad-core processors, it is uncertain whether any future eight-core processors would require two virtual server licences.
Opinion in the IT sector has been divided as to whether or not it is possible to develop licences that account for software products being run on virtual servers. Some independent software vendors have been developing licensing schemes that work on a ‘per virtual-machine’ basis, though policing the usage of software across virtual machines may require the development of more advanced monitoring tools than those currently available. Users will be hoping that, in future, the use of site licences or virtual machine based licensing models will provide the solution to the licensing problem that has so far seemed ‘virtually impossible’!
Catherine Reed is an Associate at Bristows: www.bristows.com
