Munin Statistics
From Wiki
Similiar to MRTG graphs showing Network Usage, Munin is monitoring system used to produce graphs of usage of key areas in the running of a server. Munin can produce graphs of:
- Disk Usage
- Mysql
- Network (similar to mrtg)
- Postfix Mail
- Processes
- Squid Proxy
- System - CPU, Load, Memory etc.
Contents |
Installation
(munin=graphing server, munin-node=server sending stats):
apt-get install munin munin-node
It should work out of the box. Default web is located in /var/www/munin with config files in /etc/munin with a config for munin and munin-node.
Remember to open firewall to allow munin-node to connect to the graphing server! It uses port 4949.
Temperature Monitoring with Munin
This is with a 2.6 kernel and udev!
apt-get install lm-sensors sensors-detect // The above should edit /etc/modules and include extra lines. The next line adds the sensors in manually (not to the file tho!) modprobe -a i2c-viapro i2c-isa eeprom w83627hf //A reboot should sort everything. (Cant remember if a reboot is required or not.)
Onto config of Munin. All munin templates are kept in /usr/share/munin/plugins.
ln -s /usr/share/munin/plugins/sensors_ /etc/munin/plugins/sensors_fan ln -s /usr/share/munin/plugins/sensors_ /etc/munin/plugins/sensors_temp ln -s /usr/share/munin/plugins/sensors_ /etc/munin/plugins/sensors_volt
The above lines should pick up all required - and should not need editing - once the sensor modules are included.
Test Sensors Test the sensors by simply going:
sensors
http://www.debian-administration.org/articles/229
http://munin.projects.linpro.no/wiki/Documentation
http://www.debianhelp.co.uk/munin.htm
http://www.debian-administration.org/articles/327
http://munin.projects.linpro.no/wiki/PluginCat
http://www.valerie-et-guillaume.com/categorie/geek/
SMART Monitoring with Munin
Note that smartmontools must be installed and smartd running before munin will pick up and use smart. Configure smart using the way mentioned on this wiki here: SMART
After SMART is running:
ln -s /usr/share/munin/plugins/smart_ /etc/munin/plugins/smart_sda ln -s /usr/share/munin/plugins/smart_ /etc/munin/plugins/smart_sda //edit the following: vi /etc/munin/plugin-conf.d/munin-node #uncomment #[smart_*] #user root #include [smart_sda] user root env.smartargs -d ata -a [smart_sdb] user root env.smartargs -d ata -a
That should do it. Apologies for the lack of a reference.
Potential Problems
On Ubuntu edgy, I apt-get install munin munin-node. After a couple of minutes, munin would run - however NO graphs would be generated in /var/www/munin. The template html page would be there with the localhost.localdomain, however NO info or NO graphs would appear.
After looking in:
/var/lib/munin/
I saw that all the rrd files were there!!! Its just that they were not been parsed and made into PNG's etc. ALL rrd and munin packages, recommended pages were all installed.
I decided to use the munin-graph tool to see if it would look at the rrd files and whether it would throw an error relating to a version of perl etc. Although - running this as root is not recommended as it will mess up ALL permissions I needed to try it. So I ran:
/usr/share/munin/munin-graph --force-root /usr/share/munin/munin-html --force-root
I got errors!! Something about choke etc. After running the above for another few times - it seemed to iron itself out. I reset back all the permissions, and let cron run it as munin, and THANKFULLY it worked. That solved it for me. Normally munin will run out of the box (which is great), however it needed a bit of persuasion on Ubuntu edgy.
Specific Problem with /etc/munin/plugins/postfix_mailstats on Ubuntu Feisty and Debian Etch
The error was:
Use of uninitialized value in pattern match (m//) at /etc/munin/plugins/postfix_mailstats line 239, <LOGFILE> line 14. Modification of a read-only value attempted at /etc/munin/plugins/postfix_mailstats line 239, <LOGFILE> line 14. 2007/05/18-20:30:05 Plugin "postfix_mailstats" exited with status 2304. ---- 2007/05/18-20:30:15 Server closing!
The known fix was:
vi /etc/munin/plugins/postfix_mailstats #on line 239 change from: $cause = 'OTHER' unless $1 =/^\d+$/; #to: $cause = 'OTHER' unless $1 =~/^\d+$/;
That should solve that little error. Restart munin-node and then see. Reference: http://www.nabble.com/Bug-403341:-munin-node:-missing-~-in-postfix_mailstats:239-breaks-plugin-t2831828.html
The exact same problem was found on Debian Etch. The above fixed it also. Another reference to this problem can be found at: http://www.bluequartz.us/phpBB2/viewtopic.php?t=22694&sid=585e9869ebc13d17503c2fa307ab606a
Disk Usage (DU) Monitoring of home and mail Directories plugin for Munin
The following file is placed in: /usr/share/munin/plugins/du
#!/usr/bin/perl -w
#
# Copyright (C) 2006 Philipp Gruber <pg@flupps.net>
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
#
#
#
#
#
# This munin-plugin shows the size of every users home directory in a
# munin-diagram.
#
# Because calculating the size every 5 minutes would take very long, it reads
# the size from the file /tmp/munin-homedirs.cache
#
# You need to add the following line to the crontab of root, to generate the
# file every hour. This has to be done by root, because other users probably
# don't have read access to all home directories.
#
# 0 * * * * du -B 1 --max-depth=1 /home | grep -Ev 'home$' > /tmp/munin-homedirs.cache
#
# You must also make sure, that munin is allowed to read this file.
#
#
#%# family=contrib
#open (HOME,"ls /home|");
open (HOME, "cat /tmp/munin-du.cache | cut -f 2|");
@users = <HOME>;
close(HOME);
if ($ARGV[0] and $ARGV[0] eq "config") {
print "graph_title Size of selected directories\n";
print "graph_args --base 1024 -l 1\n";
print "graph_vlabel Bytes\n";
foreach $user (@users) {
$user =~ s![^a-zA-Z0-9_ \/\n]!_!g;
$user =~ s/\n//gsm;
print "$user.label $user\n";
}
exit 0;
}
open (WHO,"cat /tmp/munin-du.cache |");
@who = <WHO>;
close (WHO);
my %logins;
foreach $user (@users) {
$user =~ s/\n//gsm;
$logins{$user} = 0;
}
my $free = `df -P -B 1 / | tail -n1 | awk '{ print \$4 }'`;
foreach $user (@who) {
$user =~ s![^a-zA-Z0-9_ \/\n]!_!g;
print "$user";
}
# vim:syntax=perl
Note: The above file is modified from the original which can be obtained at: http://munin.projects.linpro.no/wiki/plugin-homedirs http://www.mega2000.de/~philipp/homedirs
The above munin plugin reads the information from a temp file in /tmp/munin-du.cache. A cronjob running once daily refreshes this cache file. The following command is used for the cronjob:
#!/bin/bash du -B 1 --max-depth=1 /home /srv /var /tmp /usr | sort -nr | grep -Ev '/home$' | grep -Ev '/var$' | grep -Ev '/usr$' | grep -Ev '/srv$' | sed "s/\//-/g" > /tmp/munin-du.cache #Its not very tidy, I know, but it does the trick.
Munin Monitoring of Xen CPU and Network Traffic
The following websites provide the original information:
http://munin.projects.linpro.no/attachment/wiki/PluginCat/xen_traffic_all
http://www.skullkrusher.net/linux/scripts/xen_percent (Original source: http://lists.xensource.com/archives/html/xen-users/2006-01/msg00323.html )
cd /usr/share/munin/plugins/ wget http://wiki.kartbuilding.net/xen_traffic_all wget http://wiki.kartbuilding.net/xen_cpu_percent chmod 755 xen_traffic_all xen_cpu_percent ln -s /usr/share/munin/plugins/xen_traffic_all /etc/munin/plugins/ ln -s /usr/share/munin/plugins/xen_cpu_percent /etc/munin/plugins/ vi /etc/munin/plugin-conf.d/munin-node #add the following: [xen_traffic_all] user root [xen_percent] user root /etc/init.d/munin-node restart
That should do it.
Information obtained from:
http://www.debian-administration.org/articles/229
Email Notifications from Munin
Typically I use nagios to monitor services, while munin monitors individual systems, with each system having munin-node installed. Instead of having nice pretty graphs to monitor performance on an hourly, daily or weekely basis, munin can easily be set to send warning and critical email notifications.
The information on notifications using munin is quite scarse. It took quite a bit of trial and error to get everything fully corrected. Below is the most simple config. It sends one email when a service is exceeded. It sends a final email when the service is below the threshold set.
vi /etc/munin/munin.conf
#include the following:
contact.me.command mail -s "Munin Notification ${var:host} ${var:graph_title}" user@emailaddress.com
# a simple host tree
[server.domain.com]
address 127.0.0.1
use_node_name yes
df._dev_sda1.warning 90
df._dev_sda1.critical 95
Its that simple. With a minimum of two entries all can be up and running. Now, lets explain a little:
The values/variable which will be monitored can be obtained on the client/host running munin-node using munin-run. For example, we want to monitor postfix mail usage with Munin and to send email notifications if queues are exceeded.
ssh root@mail cd /etc/munin/plugins ls munin-run postfix_mailqueue #If there is no postfix in the plugins folder, try: #munin-run df #Take the values which were returned and keep note. exit #exit ssh on the mail host. ssh root@muninserver vi /etc/munin/munin.conf [mail.domain.com] address 192.168.1.10 use_node_name yes postfix_mailqueue.active.warning 90
See the following for allowing contacts for particular servers and/or for particular services: http://munin.projects.linpro.no/wiki/HowToContactNagios
contact.nagios.command /usr/local/nagios/bin/send_nsca nagioshost.example.com -c /usr/local/nagios/etc/send_nsca.cfg -to 60
contacts no # Disables warning on a system-wide basis.
[example.com;]
contacts nagios # Enables warning through the "nagios" contact for the group example.com
[foo.example.com]
address localhost
contacts no # Disables warning for all plugins on the host foo.example.com.
[example.com;bar.example.com]
address bar.example.com
df.contacts no # Disables warning on the df plugin only.
df.notify_alias Disk usage # Uses the title "Disk usage" when sending warnings through munin-limits
# Useful if the receiving end does not accept all kinds of characters
# NB: Only available in Munin-1.2.5 or with the patch described in ticket 34.
Summary of Checks
pluginname.service.warning 90
pluginname.service.critical 95
pluginname = ls /etc/munin/plugins/
servicename = munin-run pluginname
Subject Title of Email
contact.me.command mail -s "Munin Notification ${var:host} ${var:graph_title}" user@emailaddress.com
A list of the ${var:host} etc. can be found at: http://munin.projects.linpro.no/wiki/MuninAlertVariables
Number of Alerts (max messages). I didnt bother setting this. More info can be found at: http://munin.projects.linpro.no/wiki/contact.contact.max_messages
Munin via CGI (Reduce CPU Load)
As the cpu usage of Munin creating graphs every 5 minutes takes quite a while, munin ships with a cgi script which will render the graphs with all the data. By default the munin-cgi-graph (cgi) is installed with munin. To enable, do the following:
vi /etc/munin/munin.conf
graph_strategy cgi
apt-get install libdate-manip-perl
vi /etc/apache2/sites-enabled/monitor
ScriptAlias /cgi-bin/munin-cgi-graph /usr/lib/cgi-bin/munin-cgi-graph
/etc/init.d/apache2 reload
chgrp www-data /var/log/munin /var/log/munin/munin-graph.log
chmod g+w /var/log/munin /var/log/munin/munin-graph.log
chgrp -R www-data /var/www/munin/yourdomain
chmod -R g+w /var/www/munin/yourdomain
vi /etc/logrotate.d/munin
#under /var/log/munin/munin-graph.log { change:
#create 640 munin adm
create 660 munin www-data
Wait 5 minutes for munin to rebuild the html pages. Take a look at the source and you will see something like:
<img src="/cgi-bin/munin-cgi-graph/burkesys.com/twister.burkesys.com/apache_watch_requests-day.png"...
If you see an error or a blank page or a error 500:
tail /var/log/apache2/error.log #the above error file will reveal all errors.
References:
http://waste.mandragor.org/munin_tutorial/munin.html
http://munin.projects.linpro.no/wiki/CgiHowto
Another option for munin (to reduce cpu load) is to edit /etc/cron.d/munin and change the graphing only to per hour.
Extra Links
http://edseek.com/archives/2006/07/13/munin-alert-email-notification/
http://munin.projects.linpro.no/wiki/HowToContact
http://munin.projects.linpro.no/wiki/munin-man
http://munin.projects.linpro.no/wiki/munin.conf
