You may want to use a non-default template as a basis for Disposable VM. One example is to use a less-trusted template with some less trusted, 3rd party, often unsigned, applications installed, such as e.g. 3rd part printer drivers.
In order to regenerate the Disposable VM "snapshot" (called 'savefile' on Qubes) one can use the following command in Dom0:
This would create a new Disposable VM savefile based on the custom template. Now, whenever one opens a file (from any AppVM) in a Disposable VM, a Disposable VM based on this template will be used.
One can easily verify if the new Disposable VM template is indeed based on a custom template (in the example below the template called "f17-yellow" was used as a basis for the Disposable VM):
1. Start a terminal in the `fedora-20-x64-dvm` TemplateVM by running the following command in a dom0 terminal. (By default, this TemplateVM is not shown in Qubes VM Manager. However, it can be shown by selecting "Show/Hide internal VMs.")
2. Change the VM's settings and/or applications, as desired. Note that currently Qubes supports exactly one DispVM template, so any changes you make here will affect all DispVMs. Some examples of changes you may want to make include:
- Changing the DispVM's default NetVM. For example, you may wish to set the NetVM to "none." Then, whenever you start a new DispVM, you can choose your desired ProxyVM manually (by changing the newly-started DipsVMs settings). This is useful if you sometimes wish to use a DispVM with a TorVM, for example. It is also useful if you sometimes wish to open untrusted files in a network-disconnected DispVM.
3. Create an empty `/home/user/.qubes-dispvm-customized` file: