Our server restarted but no logs in /var/log/messages for this.

Issue

• One of our servers restarted but no logs in /var/log/messages for this. kindly let us know why and where went wrong on this. Messages similar to the following preceded the reboot:

Jul 18 12:02:02 <hostname> init: tty (/dev/tty2) main process (<PID>) killed by TERM signal
Jul 18 12:02:02 <hostname> init: tty (/dev/tty3) main process (<PID>) killed by TERM signal
Jul 18 12:02:02 <hostname> init: tty (/dev/tty4) main process (<PID>) killed by TERM signal
Jul 18 12:02:02 <hostname> init: tty (/dev/tty5) main process (<PID>) killed by TERM signal
Jul 18 12:02:02 <hostname> init: tty (/dev/tty6) main process (<PID>) killed by TERM signal
<snip>
Jul 18 12:02:08 <hostname> rsyslogd: [origin software="rsyslogd" swVersion="5.8.10" x-pid="1257" x-info="http://www.rsyslog.com";] exiting on signal 15.