Yesterday, one of my 3 3.2.1 hosts rebooted. I have looked in the 'events' for this server in the OVS manager, and also in /var/log on the host, but I don't see anything that tells me WHY it rebooted.
Can someone tell me where to look? Shouldn't I see a 'kernel oops' or something, somewhere?
If there's nothing in the system log file...
xen1:~ # grep boot /var/log/messages
Jan 20 19:41:12 xen1 shutdown: shutting down for system reboot
Check to see if the system was manually rebooted by using the last facility. +(Hint: Look for the user "reboot".)+
Otherwise, assuming that your system has hardware logging, I recommend checking the system BIOS system log to see if there were any hardware related failures (e.g., CPU temperature, power supply anomalies, etc).