Every TemplateBasedVM in Qubes is, as the name implies, based on some TemplateVM. The TemplateVM is where all the software available to TemplateBasedVMs is installed. The default template is based on Fedora, but there are additional templates based on other Linux distributions. There are also templates available with or without certain software preinstalled. The concept of TemplateVMs is initially described here. The technical details of this implementation are described in the developer documentation here.
Some templates are available in ready-to-use binary form, but some of them are available only as source code, which can be built using the Qubes Builder. In particular, some template “flavors” are available in source code form only. Take a look at the Qubes Builder documentation for instructions on how to compile them.
To reinstall a currently installed TemplateVM, see here.
Invisible Things Lab (ITL) Supported templates
These are the templates ITL builds and releases updates for. ITL guarantees that the binary updates are compiled from exactly the same source code as we publish.
Community Supported templates
These templates are supported by the Qubes community. Some of them are available in ready-to-use binary package form (built by ITL), while others are available only in source code form. In all cases ITL, does not provide updates for these templates. However, such updates may be provided by the template maintainer.
By installing these templates, you are trusting not only ITL and the distribution maintainers, but also the template maintainer. In addition, these templates may be somewhat less stable, since ITL does not test them.
Whenever a TemplateBasedVM is created, the contents of the
/homedirectory of its parent TemplateVM are copied to the child TemplateBasedVM’s
/home. From that point onward, the child TemplateBasedVM’s
/homeis independent from its parent TemplateVM’s
/home, which means that any subsequent changes to the parent TemplateVM’s
/homewill no longer affect the child TemplateBasedVM’s
Once a TemplateBasedVM has been created, any changes in its
/rw/configdirectories will be persistent across reboots, which means that any files stored there will still be available after restarting the TemplateBasedVM. No changes in any other directories in TemplateBasedVMs persist in this manner. If you would like to make changes in other directories which do persist in this manner, you must make those changes in the parent TemplateVM.
Templates are not automatically updated when updating dom0. This is by design, since doing so would cause all user modifications to templates to be lost. Instead, you should update your templates from within each template. If you do want to update a template from dom0 (and thereby lose any user modifications in the existing template), you must first uninstall the existing template from dom0:
$ sudo yum remove qubes-template-fedora-25
Standalone VMs using Template VMs as a basis can be created easily. These VMs receive a copy of the operating system and do not get automatically updated when Template VMs are updated–they must be updated individually.
Template VMs can occupy more space on the dom0 filesystem than necessary because they cannot employ automatic TRIM/discard on the root fs. The
qvm-trim-templatecommand in dom0 is used to recover this unused space.
Conversely, the root filesystems in Standalone VMs can employ TRIM/discard on the root fs using normal tools and configuration options.
On XFCE based Dom0, a manual action may be required to remove the “Start Menu” sub-menu of the removed TemplateVM. For example, to remove a dangling sub-menu for a removed “fedora-25” template, open a Dom0 Terminal and type:
$ rm ~/.local/share/applications/fedora-25-*
Just make sure there are no other TemplateVMs whose names start with “fedora-25” or else their menu items will be removed too.