[libvirt-users] Snapshots - can't take a snapshot with running VM

Julian Robbins julian.robbins at q-par.com
Thu Jun 17 10:40:56 UTC 2010


On 15/06/10 17:53, Julian Robbins wrote:
>> >  Can I really only create snapshots of a vm when it isnt running ?
>> No, you should be able to take a snapshot both while it is running and
>> while it is off.  However, they use different mechanisms so there 
>> could be
>> a bug in the online version.  What version of qemu/kvm are you running?
>> Also, do you have apparmor enabled/running?  If so, and if the 
>> apparmor policy
>> hasn't been updated, that might be the source of your problems.
>
> I've disabled AppArmor for now and it works fine, so there is some 
> unwanted issue there. Strangely, looking again apparmor is still 
> enabled when guest is running after reboot. Possibly rebooting the 
> guest and using dynamic appamor instead of static has helped ?
>
> I'm using vers 1.84 of QEMU/Kvm from dnjl's PPA for Lucid.

After trying again, I can no longer get snapshots to work whilst vm 
guest in running.

I have disabled apparmor so that it is only in 'complain' mode on the 
host, but still get :-

Error -5 while writing VM

whilst trying a

virsh # snapshot-create openerp

Whether running virsh as normal user or root. I'm also getting

'libvirtError: Timed out during operation: cannot acquirestate change lock' errors too, after I've tried to take a snapshot.


So it appears that perhaps there is a bug where snapshots cannot always 
be made online. I have taken some successful snapshots online, but none 
recently.

Interestingly, I can never get the 'Security' setting in the guest to 
stick to be 'none' for the apparmor Model either static or dynamic. Even 
after a reboot of the guest, the setting stays always to dynamic.

Hoping someone can help - don't want to leave using KVM/libvirt .....

-- 
Kind regards

Julian




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