Desktop Application virtualisation separates the application not just from the underlying hardware but also from the operating system. That means, for example, that you can run applications side by side in separate virtualised spaces without fear of clashes between them or with the operating system.
Application virtualisation is primarily seen as a desktop technology. A key advantage is that you can deliver applications in a variety of ways because they are independent of the client architecture, .
Just a mirage
Applications can be installed inside their own virtualised space on the client, or they can be streamed so that the user sees only an image of the application, with almost no code downloaded. You can deploy applications quickly and manage them centrally, keeping users current with security patches and updates.
This can be a big win for users. There is often a tension between the device they use and the applications they need to do their job. Sometimes these applications are supported on the device they want, but all too often they are not.
Allowing users to select their device and know that pretty much any application will run on it could be a big selling point.
Peace and harmony
Application virtualisation is also a big time-saver. Regression testing almost disappears, speeding up deployment: you test once inside the virtual environment, and the application is ready to go. Dependencies and conflicts with operating systems, hardware drivers or other applications can almost disappear.
It helps with licence management and application provisioning too. You know where all the applications are deployed at any time and how many users are accessing each one, and you can analyse the data.
Effectively, it's a step in the direction of a private cloud
You can, for example, look up the maximum number of concurrent users and incorporate that intelligence into your licence purchasing plans – you might be surprised to discover how many unused licences the company has bought.
And when it's time for an application to be retired, you just delete it from the server: no more uncertainty about whether there are unlicensed copies still being used out there.
You can see how this kind of fine-grained access to application usage could help to apply chargeback mechanisms. Effectively, it's a step in the direction of a private cloud.
Keep it simple
Server applications can be virtualised too, for many of the same reasons that apply to desktop applications and with similar advantages. For example, it simplifies application and operating system updates and deployment, resulting in fewer application images to maintain and a reduction in management costs.
This is especially useful for server applications, which are usually much more complex to install and configure than desktop applications. Additionally, server applications are tightly coupled into virtual machine images, making it tough to update either without disruption. Once the application is virtualised, this problem is mitigated to a large degree.
As with any technology, there are disadvantages. Application virtualisation adds complexity - the bugbear of any IT deployment. As we all know, the more complex it is, the more choices need to be made and the more likely it is that things will go wrong. And when they do, problems will be harder to find and eliminate.
Once the system is up and running, it will need to be maintained and managed, which is a cost item. Virtualising applications may also increase back-end costs: applications that are no longer running on client machines still need CPU time and memory, so they need to be factored into server capacity planning.
And on the desktop side, users won't take kindly to having their applications messed about with. Get it wrong and the helpdesk lines will glow.
All that said, however, virtualisation can help you deliver applications on demand, reduce testing times massively, and make application deployment easier and faster.
And on a strategic level, it may be a key element of what the finance director is promising the board right now. ®