Re: [Qemu-devel] converging around a single guest agent

[Dor Laor]

On 11/16/2011 02:07 PM, Alon Levy wrote:
> On Wed, Nov 16, 2011 at 08:53:45AM +0100, Hans de Goede wrote:
> > Hi,
> >
> > On 11/15/2011 11:39 PM, Ayal Baron wrote:
> > >
> >
> > <snip>
> >
> > > > If you want to talk about convergence, the discussion should start
> > > > around
> > > > collecting requirements.  We can then figure out if the two sets of
> > > > requirements
> > > > are strictly overlapping or if there are any requirements that are
> > > > fundamentally
> > > > in opposition.
> > >
> > > Agreed.
> > >
> > > So vdsm guest agent goal is to ease administration of VMs.  This is not saying 
> > > much as it is quite broad so I will list what is provided today and some things 
> > > we need to add:
> > >
> > > Assistance in VM life-cycle:
> > > "desktopShutdown" - Shuts the VM down gracefully from within the guest.
> > > "quiesce" - does not exist today.  This is definitely a requirement for us.
> > >
> > > SSO support for spice sessions (automatically login into guest OS using 
> > > provided credentials):
> > > "desktopLock" - lock current session, used when spice session gets disconnected 
> > > / before giving a new user access to spice session
> > > "desktopLogin"
> > > "desktopLogoff"
> > > In addition, guest reports relevant info (currently active user, session state)
> > >
> > > Monitoring and inventory:
> > > currently agent sends info periodically, which includes a lot of info which 
> > > should probably be broken down and served upon request. Info includes -
> > > - memory usage
> > > - NICs info (name, hw, inet, inet6)
> > > - appslist (list of installed apps / rpms)
> > > - OS type
> > > - guest hostname
> > > - internal file systems info (path, fs type, total space, used space)
> >
> > <snip>
> >
> > If we're gathering requirements and trying to come up with one agent to rule 
> > them all, don't forget
> > about VDI and the Spice agent. Currently the spice agent handles the following:
> >
> > 1) Paravirtual mouse (needed to get mouse coordinates right with multi monitor 
> > setups)
> > 2) Send client monitor configuration, so that the guest os can adjust its 
> > resolution
> >     (and number and place of monitors) to match the client
> > 3) Copy and paste in a platform neutral manner, if anyone wishes to add this to 
> > another agent
> >     please, please contact us (me) first. This is easy to get wrong (we went 
> > through 2 revisions
> >     of the protocol for this).
> > 4) Allow the client to request the guest to tone down the bling (for low spec 
> > clients)

I suggest we'll have a single protocol and serialization means (JSON) 
plus a common framework that manages permissions within the guest.
Beyond that, the agent should have various plugins for example the above 
spice related ones (could be also vnc ones) can be implemented as 
plugins that the ovirt agent will invoke.


> >
> As long as we are collecting requirements, even if as Ayal said merging
> spice requirements is not the OP's intent:
>
>   5) Window management - Agent can set location of windows, report
>   existing running applications and locations, get notified when a new
>   window is created. For exposing individual applications, this is a
>   future requirement.
>
> > Notes:
> > 1) All of these are client<->  guest communication, rather then the host<->  
> > guest communication
> > which the other agents seem to focus on.
> >
> > 2) Getting copy paste right requires a system level guest agent process as well 
> > as a per user
> > session agent process.
>
> > Regards,
> >
> > Hans