[libvirt-users] virsh error: domain is already quiesced

[Jérôme]

Hi all.

I'm having issues while creating snapshots.

I posted on Stack Exchange [1], but figured I might get more success 
here.

My VM backup script fails while creating the snapshot.

     virsh snapshot-create-as --domain machine_1 snap --diskspec 
vda,file=/srv/test/test-snap.qcow2 --disk-only --atomic --no-metadata 
--quiesce
     error: Requested operation is not valid: domain is already quiesced

Even after a VM reboot, the system is still quiesced and I get the same 
error.

I thought quiesce means FS freeze, but this makes no sense since I can 
still write to the FS when logged in the faulty VMs. And this would not 
survive a reboot, right?

Could it be a communication issue that makes the host think the GA says 
the machine is quiesced while it is not?

In any case, is there a command to enquire the quiesce state (apart from 
attempting a snapshot and see if I get an error)?

Assuming the faulty VMs went quiesced after a unreproducible error, I 
could fix that by exiting quiesced state, whatever that means. Is there 
a virsh command to unquiesce the VM?

The whole backup procedure used to work and now it fails on 2 VMs but 
still works on 2 others and I can't think of any relevant difference 
between them.

Software versions:

- Host is Debian Jessie with qemu-kvm 2.8+dfsg-3~bop8+1 from backports.
- Guests are Debian Stretch with qemu-guest-agent 2.8+dfsg-6+deb9u4.

(For the record, the backup script is on GitHub [2]. Basically, what it 
does is 1/ create snapshot, 2/ copy, 3/ commit snapshot.)

If I remove the `quiesce` option from the snapshot command line, things 
work smooth. But obviously, this is not ideal.

Thanks for any hint.

[1] 
https://serverfault.com/questions/917247/virsh-error-domain-is-already-quiesced
[2] https://github.com/Nobatek/vmbackup/blob/master/vmbackup

-- 
Jérôme