[one-users] libvirt persisent vs transient domains

Wed Jun 1 16:34:44 PDT 2011

Hi,

AFAIK Xen can restart VMs after a reboot of Dom0 (the configuration depends
on the xen version I think). This will automatically recover the VMs and
eventually OpenNebula will put them from unknown to active.

Cheers

Ruben

On Mon, May 16, 2011 at 11:55 PM, Piotr Kandziora <raveenpl at gmail.com>wrote:

> Hi,
>
> So, if I restart my physical nodes, all virtual machines after this
> operation will be in 'unknown' state. I can then restart them manually and
> this works. But in my solution it would be good if this happen without user
> intervention (automatic VMs start after nodes restart).
>
> Is there any good practice? Maybe one should monitor this situation and
> after restart physical nodes should be able to run VMs in automatic way
> (e.g. hooks invoked when host goes from 'err' to 'on' state)?
>
> Best regards
> Piotr Kandziora
>
>
> On Fri, Feb 18, 2011 at 6:28 PM, Ruben S. Montero <rubensm at dacya.ucm.es>wrote:
>
>> Hi,
>>
>> OpenNebula monitors VMs in unknown state. So, if the VMs are restarted,
>> OpenNebula should be able to recover those VMs and move them from unknown to
>> running. The requirement is to and the id's are preserved at the hypervisor
>> level (e.g. autostart i think)
>>
>> Cheers
>>
>> Ruben
>>
>>
>> On Fri, Feb 18, 2011 at 6:05 PM, Shi Jin <jinzishuai at gmail.com> wrote:
>>
>>> Thank you for the discussion.
>>>
>>> Yes, there is definitely a possible problem of out of sync between the
>>> host and OpenNebula.
>>> For example, after the node power failure, the one  status for the VMs
>>> would be unknown. If people then deleted the VM, restarting the VM upon
>>> power resumption would cause a problem.
>>> But this seems to be a more operational problem: just don't delete the
>>> VMs on a power failure node.
>>> There are many other ways to cause out of sync under existing OpenNebula
>>> setup and it is up to the administrator's operation to ensure everything is
>>> consistent.
>>>
>>> Also, starting a power failure VM definitely has the potential problem of
>>> disk corruption. But this is the best we can do upon such a tragic
>>> situation. One should ask more on why on the earth did the power fail in the
>>> first place? The autostart setup would simply ease a little bit of the pain.
>>>
>>> Shi
>>>
>>>
>>> On Thu, Feb 17, 2011 at 8:42 PM, Manikanta Kattamuri <
>>> mani.kattamuri at hexagrid.com> wrote:
>>>
>>>> Assume all this is set and the vm's automatically come up after the
>>>> servers get online.
>>>> would it not create more problems then solve as you one is not in sync
>>>> with all the vm states?.
>>>> If there are any monitoring tools configured based on one status, will
>>>> report failure.
>>>> Starting of the vms through oned will not succeed or cause disk
>>>> corruption?
>>>>
>>>> Mani.
>>>>
>>>> On Fri, Feb 18, 2011 at 4:03 AM, Shi Jin <jinzishuai at gmail.com> wrote:
>>>>
>>>>> Hi there,
>>>>>
>>>>> Right now, all KVM (I think Xen too but I don't know it for sure) VMs
>>>>> are started as a transient libvirt domain using the "virsh create <xml>"
>>>>> command.
>>>>> There is nothing wrong with it but recently I had a facility wide power
>>>>> failure and all VMs running on the node are gone upon the server shutdown. I
>>>>> had to manually start all the domains that were running at the point of
>>>>> failure after power is resumed. Then I thought that if I put the VMs as
>>>>> libvirt autostart domains, they will be automatically started upon boot,
>>>>> which would save me a  lot of manual process. But to do that, I have to make
>>>>> the VMs persistent libvirt domains using the "virsh define" and "virsh
>>>>> start" commands in sequence instead of the single "virsh create".
>>>>>
>>>>> Is this a good idea? Comments welcome.
>>>>> Thanks.
>>>>> Shi
>>>>>
>>>>> --
>>>>> Shi Jin, Ph.D.
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Users mailing list
>>>>> Users at lists.opennebula.org
>>>>> http://lists.opennebula.org/listinfo.cgi/users-opennebula.org
>>>>>
>>>>>
>>>>
>>>
>>>
>>> --
>>> Shi Jin, Ph.D.
>>>
>>>
>>> _______________________________________________
>>> Users mailing list
>>> Users at lists.opennebula.org
>>> http://lists.opennebula.org/listinfo.cgi/users-opennebula.org
>>>
>>>
>>
>>
>> --
>> Dr. Ruben Santiago Montero
>> Associate Professor (Profesor Titular), Complutense University of Madrid
>>
>> URL: http://dsa-research.org/doku.php?id=people:ruben
>> Weblog: http://blog.dsa-research.org/?author=7
>>
>> _______________________________________________
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>> Users at lists.opennebula.org
>> http://lists.opennebula.org/listinfo.cgi/users-opennebula.org
>>
>>
>
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>

-- 
Dr. Ruben Santiago Montero
Associate Professor (Profesor Titular), Complutense University of Madrid

URL: http://dsa-research.org/doku.php?id=people:ruben
Weblog: http://blog.dsa-research.org/?author=7
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