How to log kvm/qemu guest boot/reboot/shutdown time?

Question

I manage an Ubuntu 14.04 LTS server running several guest VMs through KVM/qemu, and I'm asked to log boot, reboot and shutdown times of guests.

Is there a way to catch this kind of events for example in /var/log/syslog?

Answer 1

I found that such events are already logged for each VM in a file named in a way similar to vmname.log, located in /var/log/libvirt/qemu/.

So one can get boot and shutdown times using a command like this:

$ sudo grep -e 'starting up' -e 'shutting down' /var/log/libvirt/qemu/vmname-log

Still can't find a way to get reboot time without looking at guest log files.