[ovirt-users] how to run command in windows guest via agent?

[Gianluca Cecchi]

On Thu, Mar 15, 2018 at 3:26 PM, Gianluca Cecchi <gianluca.cecchi at gmail.com>
wrote:

> On Thu, Mar 15, 2018 at 2:26 PM, Sergey Vavilov <sergey at vavilov.org>
> wrote:
>
>> Hello!
>>
>> I'm wondering
>> how can I run a cmd.exe command (or powershell) inside windows guest
>> virtual machine by
>> ovirt-agent from outside (from ovirt-engine or from host)?
>> What's ovirt's analogue for
>> virsh qemu-agent-command
>> ?
>> Actually, I want to setup ip on virtual NIC.
>> So I can't run a command via windows' protocols.
>> ovirt-agent service works in windows virtual machine and successfully
>> reports its state to ovirt engine.
>> But it looks like ovirt-agent isn't suitable to run commands in virtual
>> machines?
>> Or am I wrong?
>> Should I configure a coexistence of ovirt-agent and qemu-agent inside vm
>> somehow?
>> How did you solve such task before?
>>
>> Thank you, all!
>>
>>
>> --
>> Sergey Vavilov
>>
>>
> Hi Sergey,
> I recently had a need for a Windows 2008 R2 x86_64 VM that I moved from
> vSphere to RHV (but the considerations below are the same for oVirt).
> In my case I had to run a backup of an Oracle database that is in
> NOARCHIVELOG mode, due to performance reasons: it is an RDBMS used for BI
> that is refreshed every day and doesn't need a point in time recovery but
> only a consistent state before the "new day" processing is run at 01:00 in
> the night.
> In vSphere the backup of the VM was implemented with Veeam, that uses
> snaphsot technology and interacts with VSS layer of M$ operating systems.
> Oracle fully supports on Windows the backup of database using VSS only if
> it is in ARCHIVELOG mode.
> https://docs.oracle.com/cd/E11882_01/win.112/e10845/vss.htm#NTQRF475
>
> Veeam automatically executed shutdown / snapshot / start of the dabatase
> because I think it implements what in the link above is called as
> PRE_SQLCMD in OnPrepareBackup callback (through the VeeamGuestHelper.exe
> executable).
>
> Coming back to oVirt, the interaction with Windows VSS layer is indeed
> done by "QEMU guest agent"too; you have to install it together with the
> oVirt Guest Agent when you install oVirt Guest Tools
>
> So in my case I would need for Windows something similar to the
> "fsfreeze/thaw hooks" I have in Linux QEMU guest agent.
> But searching through the code it seems this functionality is only present
> in Linux component...
> In fact some days ago I wrote to the qemu-devel mailing list to ask for
> possible implementation:
> http://lists.nongnu.org/archive/html/qemu-devel/2018-03/msg02823.html
>
> No answer so far. Feel free (you and others) to contribute to the thread
> if you think it can help...
> It could also be useful to have at least writer control commands
> implementation in VSS interaction of QEMU Guest Agent in Windows, so that
> one could do something similar to what Veeam on vSphere already does...
>
> Based on what I have wrote above, I doubt you could interact at all
> through the QEMU guest agent on Windows to run any command...
> And also for Linux guests, I think you are restricted to the default
> actions (eg shutdown) or forced to use as a workaround the approach to run
> a snapshot (that then you delete) and "attach" the desired command to the
> freeze (or thaw) hook...
>
> HIH,
> Gianluca
>
>
>
Hello,
in an off-list message it appears that the qemu guest agent offers a
"guest-exec" command, but that it is not enabled into the build at
https://fedorapeople.org/groups/virt/virtio-win/direct-downloads/archive-virtio/virtio-win-0.1.141-1/

can anyone confirm this and its reasons (security? isolation?...)
Could the policy change and for example allow a choice to have it or not at
runtime?
Any hint on how to recompile enabling the feature?

Thanks,
Gianluca
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