[libvirt-users] VM Creation Timestamp

Tony Atkinson tony.atkinson at dataproservices.co.uk
Thu Feb 27 09:23:54 UTC 2014


On 26/02/14 19:02, Eric Blake wrote:
> When you say "creation timestamp", do you mean the time at which the
> qemu process was spawned (as in 'virsh create' for transient guests or
> 'virsh start' for persistent guests - basically an uptime measurement)
> or the time at which XML was first recorded for the guest (as in
> 'virsh create' or 'virsh define' - more of an initial install
> timestamp, with no bearing on actual runtime of the guest)? I'm
> assuming that you'd want live migration to preserve the timestamp, but
> what happens with reverting to snapshots or saving/restoring from
> files (which are also situations that create a new qemu process, but
> where the guest has previous uptime already accumulated)? 

sorry, our conversation got split between here and the bug report I filed.
https://bugzilla.redhat.com/show_bug.cgi?id=1070411

Just to clarify

A timestamp of when the domain is first defined.
(when the UUID for the domain is allocated)

My /particular/ use case involves tracking guest resource usage over time.
I need to maintain a consistant ordering of virtual machines.
Domain ID is not persistant, and the UUID (while unique and persistant)
is not useful for sorting.

Ideally, I would want something like

<domain type='kvm'>
  <name>banana</name>
  <uuid>b4f24019-ee69-6b4b-34a1-40f6e4126c57</uuid>
  <created>1393442012</created>
  ...
</domain>

For my particular need I've hacked the timestamp out of the apparmor
definition file

    stat --format="%Y" /etc/apparmor.d/libvirt/libvirt-${VM_UUID}

I just thought it was a useful piece of info that may be worth formally
including in the domain definition.

--
Tony Atkinson




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