Still a little fuzzy on how a qube uses the default dispvm setting

[John Smiley]

I re-read all of the docs on this topic and I think this setting determines which dvm is used when the qube asks to open a document or run a program in a dvm unless it specifies a specific dvm.

So the dvm given by this pref would by used by the Qube's File application when you select a file and choose edit or view in DisposableVM from the menu.

It would also be used when opening a file via the qube's command line with qvm-open-in-dvm or running a program with qvm-run.

Is this correct?

Did I leave anything out?

Are there any restrictions on which dvms can be used from a given domain? For example, is it valid to have a fedora-28-dvm as the default dispvm for a fedora-29 domain? Not that you would typically need to do that, but is there any reason it would not work assuming the fedora-28-dvm had the necessary software installed?

What led me to this question was cloning the provided fedora-29 templateVM to fedora-29-test-1, installing google-chrome-stable in the clone, and creating a new qube vm from the new template. The new qube still uses the original fedora-29-dvm domain for its default dispvm. It seems to work fine for viewing and editing documents in a dvm. both from the command line with qvm-open-in dvm and from Nautilus, but abends with "Service call error: Request refused" (ex: qvm-run --dispvm fedora-29-dvm terminal) or does nothing when I attempt to use qvm-run.

Do I need to create a new dvm from a domain based on the new fedora-29-test-1 template and assign that to qubes as their default dispvm for qubes based on the same template?

What is SOP wrt dvms when you create a new template and qubes based on that template?

[unman]

On Thu, Dec 27, 2018 at 06:05:42PM -0800, John Smiley wrote:
> I re-read all of the docs on this topic and I think this setting determines which dvm is used when the qube asks to open a document or run a program in a dvm unless it specifies a specific dvm.
>
> So the dvm given by this pref would by used by the Qube's File application when you select a file and choose edit or view in DisposableVM from the menu.
>
> It would also be used when opening a file via the qube's command line with qvm-open-in-dvm or running a program with qvm-run.
>
> Is this correct?

Yes.

>
> Did I leave anything out?
>

Only that it's possible to override this from within the qube, by
specifying an alternative for particular applications, using
qvm-open-in-vm '$dispvm:<DVMTemplate>. One can, for example set this in
.mailcap or in defaults file if the change is to be permanent.

> Are there any restrictions on which dvms can be used from a given domain? For example, is it valid to have a fedora-28-dvm as the default dispvm for a fedora-29 domain? Not that you would typically need to do that, but is there any reason it would not work assuming the fedora-28-dvm had the necessary software installed?
>

No - you can set as you like.

> What led me to this question was cloning the provided fedora-29 templateVM to fedora-29-test-1, installing google-chrome-stable in the clone, and creating a new qube vm from the new template. The new qube still uses the original fedora-29-dvm domain for its default dispvm. It seems to work fine for viewing and editing documents in a dvm. both from the command line with qvm-open-in dvm and from Nautilus, but abends with "Service call error: Request refused" (ex: qvm-run --dispvm fedora-29-dvm terminal) or does nothing when I attempt to use qvm-run.
>
> Do I need to create a new dvm from a domain based on the new fedora-29-test-1 template and assign that to qubes as their default dispvm for qubes based on the same template?
>
> What is SOP wrt dvms when you create a new template and qubes based on that template?

Qubes are created using the global default_dispvm, (set in qubes-prefs),
not the dispvm set for the Template. You can override this on creation
with qvm-create or update the setting using qvm-prefs.
You dont *need* to create a new dvmTemplate, but you can do so if you
wish. Remember that you can use any qube as a dvmTemplate, so you can
configure a qube, clone it and set netvm none, and have one online and
one offline. Then you can use these as dvmTemplates to have online and
offline disposableVMs, called as you wish.