Virtualisation has always been an interesting and intriguing topic, yet most of us do not know enough about it. The concept of virtualisation brings to our minds whole operating systems residing inside virtual machines, though this is not the only meaning of virtualisation, as you will learn. Altiris Software Virtualization Solution (SVS) 2 aims to virtualise not complete operating systems, but parts of it, so that you can install software applications inside these virtual “packages,” leaving the operating system unscathed, in the event that the application malfunctions. This is like placing a polythene bag containing newly-bought fish in an aquarium to monitor if they adapt well to their new surroundings, before releasing them into the water. It is therefore a very useful tool to install and test beta versions of applications.
Creating a new layer
Software testers would surely find this indispensable. We have already mentioned it in the Bazaar section of our January 2007 issue; we now show you how to play around with this gem of an application.
This is a 1.8 MB download available at www.altiris.com. It is free for personal use, and you can obtain a free personal license from the site, which is necessary for the installation to continue. Do not forget to check the box next to the admin tool option, which lets you create virtual software packages. Restart the computer after the setup completes.
Create A Virtual Software Layer
A Virtual Software Layer needs to be created to capture the installation of your test application (Eudora in this case). All the installed files, Registry settings, and application settings will be captured and stored in this layer, isolated from your OS. In the SVS Admin tool, select File > Create New Layer, choose Install Application, and click Next. Give an identifiable name to this layer and click Next. Select the capture method; here, choose “Single program capture”, click Browse, navigate to the setup files of the test application, select it, click Next, and then click Finish.
The Global capture option is used to capture any and all changes made to the system, and thus is useful if you wish to install more than one application. Note that a layer has two parts; one is read-only, and it stores the installation stage of the application until the capture is terminated, while the other is the writeable part of the layer, which stores changes caused to or by the program when the user interacts with it later. An animated capture icon (“yellow lightning”) appears in the System Tray; the animation indicates that the capture is in progress. The test application installer will be launched, and you can complete the installation of that program as you normally would.
Launch the test program, and if there is any first-time configuration, it will be saved to the read-only part of the layer too, like the rest of the installation. Right-click on the flashing icon in the System Tray and select “Stop Capture” to end the capture process. If you run the configuration of the test program after the capture part ends, it will be saved in the writeable part of the layer.
Test, Activate, And Deactivate The Layer
The layer created in the previous step is in the activated state by default, meaning that the contents of this layer (Eudora in this case) are visible to the user. To activate or deactivate a layer, in the SVS Admin window. Right-click on the layer in question, and click on Activate or Deactivate as required.
Deactivating a new layer
If you deactivate the layer in our example, you will find that all instances of Eudora in Windows, including the program folders and icons as well as the Registry entries, will vanish without a trace. You should test the layer by launching the application; if the application runs well, the layer is working properly.
Modify The Layer
You can modify the properties of a layer, but to do this, you need to first deactivate it. You can then right-click on the layer in SVS Admin and select “Edit Layer Properties”. A new Edit Layer window will open, where you can edit the properties of the layer such as to modify the installed files and Registry entries. This is something we wouldn’t have advised you to carry out, had the application been installed normally in Windows, but in this case, we encourage you to get your hands dirty because your OS is safe: the layer is isolated from it. So if anything goes wrong, you can simply restore the layer by right-clicking on it and selecting Reset Layer.
Editing layer properties
Making A Distributable Application Package
If you have multiple computers, you can deploy a certain application on all the computers using Altiris SVS.
Install the application on the primary computer with Altiris SVS installed and store it in the layer as explained before. Deactivate the layer. Right-click on the layer, select “Export Layer”, and save it as a Virtual Software Package (.VSA) file.
Now install Altiris SVS on all the other computers and copy the VSA file you created to those computers. Launch Altiris SVS Admin on the other computers, click File > Import from Archive, and open the VSA file. That’s it-your application will appear as if it had already been installed and ready to use.
Bear in mind that there are currently certain limitations to Altiris SVS, such as drivers, virus checkers, file encryption products, OS patches, and computer management agents. Also, you cannot encrypt files in a layer, i.e. files pertaining to application(s) installed in a layer.
Now that you have the tools of the trade and we’ve already got you started, why not give it a try? Become a software tester!