[libvirt-users] disappeared VM in virsh

[Akendo]

On 08/16/2012 06:35 PM, Eric Blake wrote:
> On 08/16/2012 08:14 AM, Akendo wrote:
>> Hi guys,
>>
>> one of my VM has disappeared in libvirtd. I still can see the process
>> with ps and the configuration file is as well there. But it is not
>> displayed or found with virt-manger/virsh.
>>
>> virsh list shows only 4 of 5, but there is no real error message.
>> I restarted the daemon without solving the problem. Any idea what to do?
> 
> Most likely, this happened because you upgraded libvirt versions, and
> the file in /var/run/libvirt/qemu corresponding to the disappearing
> guest contained information placed by the older libvirt that the newer
> libvirt does not understand.  Could you please locate and send that xml
> file for analysis, along with more precise information about your
> current libvirt, and whether or not you just recently upgraded libvirt?
>  Also, were there any messages in libvirtd.log around the point where
> you restarted libvirtd, about unrecognized XML for the disappearing guest?
> 
>>
>> Here some info:
>>
>> Compiled against library: libvir 0.9.13
> 
> Was this self-built from upstream tarballs?  And if so, did you remember
> to also apply the RHEL-specific patches that were present on the older
> distro version of libvirt?  After all,
> 
>>
>> It's a CentOS 6
> 
> CentOS 6 ships a version of libvirt based on RHEL, and RHEL 6.3 only
> ships with libvirt 0.9.10 + patches.  Some of those patches are
> important to preserve if you want a clean upgrade path.
> 
> Is the disappearing guest one that you don't mind restarting?  If so,
> and my guess about upgrading to self-built libvirt is correct, then
> downgrade back to the libvirt that you had previously installed (you
> should then see the guest listed again), stop it, then upgrade to the
> new libvirt, and now you should be able to start the guest.  And if that
> does work, comparing the two versions of /var/run/libvirt/qemu/$dom.xml
> (old libvirt vs. new libvirt) may help us identify what specific patch
> from the old libvirt is causing grief in the self-built new libvirt.
> 
> 
> 
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> 
Thank you very much for you reply. I upgraded the CentOS 6.3 some days
ago, but this is a default version of CentOS.

I restarted the libvirtd without success of finding my VM. But very
interesting is the fact there is a $dom.xml for my VM. Also is a
$DOM.pid file.

But i found another problem: our system has 12 cores i allowed to use 8
cores which raise this error message:
error : virDomainDefParseXML:8871 : Maximum CPUs greater than topology limit

This error message has for some reason suppress in the syslog (lor i
just didn't read right...) i reduced the amount of CPU to 4. Now it's
working again.


so far
Thank you for the help.