libvirt users - Feb 2015 - Adding timestamps for all emulator output

Hello,

I think it would be useful if libvirt will be able to prefix all
messages from emulator pipes with the date stamping, for example I am
trying to catch very rare and non-fatal race with

virtio-serial-bus: Guest failure in adding device virtio-serial0.0

which is specific to the Windows guests on qemu-kvm. I have supporting
infrastructure which can tell me exact times for every action upon
this VM, but as bug is not frequent, the continuous monitoring looks
like an overkill for a desired goal - find a correlation between
emulator event and message from stderr. Patching emulator itself is
barely an option, as it is ugly, requires refresh of the running code
via loopback migration and completely non-universal, as every
hypervisor should be modified seperately.

I`d highly appreciate positive consideration for such functionality
addition or can write a patch shortly, if needed. Thanks!

On Thu, Feb 26, 2015 at 06:29:49PM +0400, Andrey Korolyov
wrote:
> Hello,
> 
> I think it would be useful if libvirt will be able to prefix all
> messages from emulator pipes with the date stamping, for example I am
> trying to catch very rare and non-fatal race with
> 
> virtio-serial-bus: Guest failure in adding device virtio-serial0.0
> 
> which is specific to the Windows guests on qemu-kvm. I have supporting
> infrastructure which can tell me exact times for every action upon
> this VM, but as bug is not frequent, the continuous monitoring looks
> like an overkill for a desired goal - find a correlation between
> emulator event and message from stderr. Patching emulator itself is
> barely an option, as it is ugly, requires refresh of the running code
> via loopback migration and completely non-universal, as every
> hypervisor should be modified seperately.
> 
> I`d highly appreciate positive consideration for such functionality
> addition or can write a patch shortly, if needed. Thanks!
Just set 'log_timestamp' in /etc/libvirt/qemu.conf and QEMU will then
include a timestamp in any messages it writes to the stderr log file.

Regards,
Daniel
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On Thu, Feb 26, 2015 at 5:36 PM, Daniel P. Berrange <berrange@redhat.com>
wrote:
> On Thu, Feb 26, 2015 at 06:29:49PM +0400, Andrey Korolyov wrote:
>> Hello,
>>
>> I think it would be useful if libvirt will be able to prefix all
>> messages from emulator pipes with the date stamping, for example I am
>> trying to catch very rare and non-fatal race with
>>
>> virtio-serial-bus: Guest failure in adding device virtio-serial0.0
>>
>> which is specific to the Windows guests on qemu-kvm. I have supporting
>> infrastructure which can tell me exact times for every action upon
>> this VM, but as bug is not frequent, the continuous monitoring looks
>> like an overkill for a desired goal - find a correlation between
>> emulator event and message from stderr. Patching emulator itself is
>> barely an option, as it is ugly, requires refresh of the running code
>> via loopback migration and completely non-universal, as every
>> hypervisor should be modified seperately.
>>
>> I`d highly appreciate positive consideration for such functionality
>> addition or can write a patch shortly, if needed. Thanks!
>
> Just set 'log_timestamp' in /etc/libvirt/qemu.conf and QEMU will
then
> include a timestamp in any messages it writes to the stderr log file.


Thanks Daniel, this will definitely help me! Anyway, is the more
generic way to add timestamps in libvirt for any given hypervisor is
not created by a reason, say, incompatibility at some point?