[Users] concurrent SPICE access [was: Re: oVirt 3.5 planning]

[Michal Skrivanek]

On Feb 27, 2014, at 10:19 , Markus Stockhausen <stockhausen at collogia.de> wrote:

>> Von: users-bounces at ovirt.org [users-bounces at ovirt.org]&quot; im Auftrag von &quot;Itamar Heim [iheim at redhat.com]
>> Gesendet: Donnerstag, 27. Februar 2014 09:53
>> An: Sven Kieske; users at ovirt.org
>> Betreff: Re: [Users] concurrent SPICE access [was: Re:  oVirt 3.5 planning]
>> 
>> On 02/27/2014 10:52 AM, Itamar Heim wrote:
>>> On 02/27/2014 10:51 AM, Sven Kieske wrote:
>>>> Well, you generate a separate ticket to the same vm.
>>>> resulting in another vnc-session to the server, but the input/output
>>>> is shared, you can see in real time when the other user types etc.
>>> 
>>> iirc, the ticketing mechanism works in a way that a new ticket
>>> disconnects the previous session?
>> 
>> (on connection with the new ticket)
> 
> In the VNC case this does not work. I do not know if its by design or
> just a bug/feature. Either Ovirt does not instruct libvirt to create a new
> VNC ticket with option "disconnect all connected clients" or this 
> information is not correctly interpreted by qemu.

well, sort of both. We keep the QEMU/libvirt  default which is to honor client's request.
Which is in case of novnc by default "shared", other common clients like vncviewer default to "disconnect"

I wonder if anyone is using the shared behavior or we should disallow it. Or make it optional, which is nice but as always comes with a price of development time.

> 
> If you launch a client that initiates a shared connection to the console 
> then existing connections will stay open. This magically works if you
> use the novnc client (as Sven explained).
> 
> The only thing that prevents a concurrent access to the console with
> virt-viewer is the fact that it enforces a single VNC connection.

yes

> 
> So state is as follows:
> 
> SPICE: disconnect happens during ticket creation

It's on connection as well, it just can't be controlled (not that it matters:)

Thanks,
michal


> VNC: disconnect may happen during client connection
> 
> You can check that behaviour if you associate a .VV file with a text editor. 
> With SPICE the existing console connection is terminated just before the
> .VV file opens in the editor. With VNC the existing session stays open.
> 
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