After running "uptime" command I discovered that my server rebooted a few days ago. I'm trying to find out who did it by running a "last" command. But the result is rather confusing for me. Normally the output gives you a bunch of lines that looks similar to this:

<user> pts/3...........<server>.....Mon Feb 24 13:04 - 15:05 (1+02:00)

However, one of the output, which is the actual date and time that the reboot is suspected to have happen, shows this:

reboot system boot 2.6.18-371.1.2.el5 Fri Mar 14 12:30 (5+06:20)

Does the output above mean that the system rebooted by itself? How come there's no username and server name associated with that reboot? Any assistance would be much appreciated.

reboot means the system came up at that time. The line is logged by pseudo-user "reboot". last has no idea what caused the system to go down. The lines just before reboot tell you who was logged in at the time, but nothing can tell you if someone pulled the plug out and then restarted the system, for example.

Okay, so, how do we then determine why a certain server shutdown? I believe /var/log/messages logs the boot up and shutdown of a system. If there are messages indicating the bootup but no shutdown before it, could we assume that the shutdown was caused by things like power outages?

Cheers!

Hi,

Can you not do:
Or grep for "shutdown" or "reboot"... Look in the .bash_history.

Xen.

As smallpond indicated, use the 'reboot' timestamp as a guide and investigate the logfiles for recs immediately before that and check who was logged on at the time.