I don't think "virsh shutdown" and "virsh destroy" are "triggers".
I think when the guest rebooted something went wrong and subsequent attempts to use "virsh shutdown" and "virsh destroy" fail.
This morning the en-mass VM guest reboot was triggered by cron jobs inside the guests.
I tried unsuccessfully to reproduce this on a VM host that only has a single VM guest. I'm still investigating if having several VM guests reboot at the same time is the trigger or not.
I don't think "virsh shutdown" and "virsh destroy" are "triggers".
I think when the guest rebooted something went wrong and subsequent attempts to use "virsh shutdown" and "virsh destroy" fail.
This morning the en-mass VM guest reboot was triggered by cron jobs inside the guests.
I tried unsuccessfully to reproduce this on a VM host that only has a single VM guest. I'm still investigating if having several VM guests reboot at the same time is the trigger or not.