Image management in a virtualised environment

Strong image management skills are required to deal with licensing issues and properly control your virtual world.

An area where Quocirca continually sees organisations struggle with when it comes to virtualisation is image management. We're not looking at how well an organisation manages its brand in the market but how they look after the multiple different virtual assets under their ownership. As virtualisation spreads, organizations often find problems that weren't apparent at the start. Although virtualisation is good at squeezing the most out of existing assets, it has an unfortunate flaw in its own simplicity.

Take this example: A developer needs to check that an application they have written works as expected. There are plenty of hardware resources available, so they create an image of the application and everything else that is needed as a stack underneath it, spin it up and carry out a few tests. Things aren't working as expected, so they change a load of things and do the same routine for a new test. This probably happens several times before a working version of the application is obtained, which is then shipped off for full pre-mainstream testing, where new images will be created, provisioned and run as required.

Without control and image management, virtual images can bring down what could be a well-worked virtual infrastructure.


Clive Longbottom, Contributor,

All seems nice and simple, so where's the problem with image management? Certainly, the business has gained from faster development cycles, the developer is encouraged to carry out more testing cycles and everyone seems to have gained.

The problem comes down to how easy it is to set up a virtual image -- and how easy it is to then forget to break it down afterwards. Starting from a position of a virtualised hardware platform, a lot of other things are required before an application can run. An operating system will be needed, probably along with an application server platform. Any dependent software will need to be present as well. And it all needs to be licensed.

Herein lies the problem. If virtualisation makes it easy to create or copy images and spin them up as individuals deem necessary, then each one requires its own license stack. If the user does not deprovision the image correctly, the licenses remain there -- unused, but current, accruing the need for renewal and maintenance payments. Even if the software is based on Software as a Service (SaaS) subscription licensing, any "live" spinning image will nominally attract the need to continue paying subscriptions -- unless the image is deprovisioned correctly. Therefore, it is an imperative that image management has to be in place to manage all the licenses that are in use across a fully audited asset register of the images that are in use within an organisation.

And image management doesn't stop there
Let's assume that an organisation has a collection of images that are all necessary -- for example, 100 mission-critical images that are all provisioned in the live environment. Each of these will need to be patched or upgraded whenever any part of the stack changes -- and may also need to be fully retro-tested to ensure that everything still runs as it should. If there are also a number of unused but live extra images in the development, test and live environments, each one of these will also need to be patched or upgraded, each with at least a resource cost to the organisation.

So image management is a necessity within the virtual world, ensuring that only what needs to be licensed is licensed, minimising costs by using library functions for checking licenses in and out as required. Only images that are tagged as being live and in use need to be patched and upgraded -- any images that are not tagged as such should raise an event, notifying the owner of the image that it has been identified and giving them a period of time before the image is deprovisioned and its licenses freed up for use elsewhere.

The future may be brighter for image management
Many of the vendors have realised that image sprawl is a growing issue, and steps are now being taken to make life easier. For example, in-line provisioning of composite images are coming through. Here, a description of an image is held, rather than an image. When it becomes necessary to provision the image, the description is found and the image is built on the fly. Therefore, patching and updating is minimised -- the "golden" images of the operating system, app server and so on are stored just once and are only brought to life as and when needed.

Certainly, cloud computing adoption will also drive a need for a different way of dealing with composite applications, one where functional services can be aggregated together to facilitate business processes. This requires micro-aggregation of small subscription payments against transactional usage. Images here may be spun up and down in a matter of minutes. The thought of trying to run such a system without full image management in place should be enough to make even the hardest IT manager shudder.

Combine this approach with automatic image management, based on ageing images around variables such as lack of use or defined project lengths, and the capabilities of the virtual environment to provide ongoing support to the business at the most effective cost can be found. Unused images taking up virtual and physical resource are minimised, unused licenses are no longer taking up costs and human resources are avoided. New images can be rapidly created for use in any scenario, in the knowledge that these will be gracefully aged and any licenses freed for reuse up in a defined period of time.

Without control and image management, virtual images can bring down what could be a well-worked virtual infrastructure. So, polish up your image -- gain control now and provide a much greater level of service to your organisation!

Clive Longbottom is a service director at U.K. analyst Quocirca Ltd and a contributor to

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