Can anyone tell me why my ubuntu server went down?

Farid Rn asked:

My Ubuntu Server version 11.10 went down in middle of the night a few days ago without any reason. Now I want to know what’s the problem.

Here are some part of syslog which I can’t understand a single word. Can anyone help me point out the problem?

Server down was between 23:17:01 and 07:41:43 until we restarted it’s hardware.

Jul 15 22:55:02 my-webserver CRON[4879]: (CRON) info (No MTA installed, discarding output)
Jul 15 23:00:01 my-webserver CRON[5576]: (munin) CMD (/usr/bin/munin-cron)
Jul 15 23:00:01 my-webserver CRON[5578]: (root) CMD (if [ -x /etc/munin/plugins/apt_all ]; then /etc/munin/plugins/apt_all update 7200 12 >/dev/null; elif [ -x /etc/munin/plugins/apt ]; then /etc/munin/plugins/apt update 7200 12 >/dev/null; fi)
Jul 15 23:00:01 my-webserver CRON[5577]: (munin) CMD (if [ -x /usr/bin/munin-cron ]; then /usr/bin/munin-cron; fi)
Jul 15 23:00:02 my-webserver CRON[5575]: (CRON) error (grandchild #5576 failed with exit status 1)
Jul 15 23:00:02 my-webserver CRON[5575]: (CRON) info (No MTA installed, discarding output)
Jul 15 23:05:01 my-webserver CRON[6229]: (munin) CMD (if [ -x /usr/bin/munin-cron ]; then /usr/bin/munin-cron; fi)
Jul 15 23:05:01 my-webserver CRON[6230]: (munin) CMD (/usr/bin/munin-cron)
Jul 15 23:05:01 my-webserver CRON[6231]: (root) CMD (if [ -x /etc/munin/plugins/apt_all ]; then /etc/munin/plugins/apt_all update 7200 12 >/dev/null; elif [ -x /etc/munin/plugins/apt ]; then /etc/munin/plugins/apt update 7200 12 >/dev/null; fi)
Jul 15 23:05:01 my-webserver CRON[6226]: (CRON) error (grandchild #6229 failed with exit status 1)
Jul 15 23:05:01 my-webserver CRON[6226]: (CRON) info (No MTA installed, discarding output)
Jul 15 23:09:01 my-webserver CRON[6838]: (root) CMD (  [ -x /usr/lib/php5/maxlifetime ] && [ -d /var/lib/php5 ] && find /var/lib/php5/ -depth -mindepth 1 -maxdepth 1 -type f -cmin +$(/usr/lib/php5/maxlifetime) ! -execdir fuser -s {} 2>/dev/null \; -delete)
Jul 15 23:10:01 my-webserver CRON[8404]: (munin) CMD (if [ -x /usr/bin/munin-cron ]; then /usr/bin/munin-cron; fi)
Jul 15 23:10:01 my-webserver CRON[8405]: (root) CMD (if [ -x /etc/munin/plugins/apt_all ]; then /etc/munin/plugins/apt_all update 7200 12 >/dev/null; elif [ -x /etc/munin/plugins/apt ]; then /etc/munin/plugins/apt update 7200 12 >/dev/null; fi)
Jul 15 23:10:01 my-webserver CRON[8407]: (munin) CMD (/usr/bin/munin-cron)
Jul 15 23:10:01 my-webserver CRON[8401]: (CRON) error (grandchild #8404 failed with exit status 1)
Jul 15 23:10:01 my-webserver CRON[8401]: (CRON) info (No MTA installed, discarding output)
Jul 15 23:15:01 my-webserver CRON[9036]: (munin) CMD (if [ -x /usr/bin/munin-cron ]; then /usr/bin/munin-cron; fi)
Jul 15 23:15:01 my-webserver CRON[9035]: (munin) CMD (/usr/bin/munin-cron)
Jul 15 23:15:01 my-webserver CRON[9041]: (root) CMD (if [ -x /etc/munin/plugins/apt_all ]; then /etc/munin/plugins/apt_all update 7200 12 >/dev/null; elif [ -x /etc/munin/plugins/apt ]; then /etc/munin/plugins/apt update 7200 12 >/dev/null; fi)
Jul 15 23:15:01 my-webserver CRON[9034]: (CRON) error (grandchild #9035 failed with exit status 1)
Jul 15 23:15:01 my-webserver CRON[9034]: (CRON) info (No MTA installed, discarding output)
Jul 15 23:17:01 my-webserver CRON[9544]: (root) CMD (   cd / && run-parts --report /etc/cron.hourly)
Jul 16 07:41:43 my-webserver kernel: imklog 5.8.1, log source = /proc/kmsg started.
Jul 16 07:41:43 my-webserver rsyslogd: [origin software="rsyslogd" swVersion="5.8.1" x-pid="783" x-info="http://www.rsyslog.com"] start
Jul 16 07:41:43 my-webserver rsyslogd: rsyslogd's groupid changed to 103
Jul 16 07:41:43 my-webserver rsyslogd: rsyslogd's userid changed to 101
Jul 16 07:41:43 my-webserver rsyslogd-2039: Could no open output pipe '/dev/xconsole' [try http://www.rsyslog.com/e/2039 ]
Jul 16 07:41:43 my-webserver kernel: [    0.000000] Initializing cgroup subsys cpuset
Jul 16 07:41:43 my-webserver kernel: [    0.000000] Initializing cgroup subsys cpu
Jul 16 07:41:43 my-webserver kernel: [    0.000000] Linux version 3.0.0-12-server ([email protected]) (gcc version 4.6.1 (Ubuntu/Linaro 4.6.1-9ubuntu3) ) #20-Ubuntu SMP Fri Oct 7 16:36:30 UTC 2011 (Ubuntu 3.0.0-12.20-server 3.0.4)

My answer:


I see two possibilities:

  1. Your location suffered a power failure around 23:17 and power was restored around 07:41.

  2. Someone who is at your company overnight decided to unplug the computer.


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