Difference between revisions of "Munin"

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Basically all plugins are installed in the following manner (although there are exceptions, review each plugin!):
 
Basically all plugins are installed in the following manner (although there are exceptions, review each plugin!):
  
 +
  (This is on each system running munin-node)
 
   cp <pluign> /usr/lib/munin/plugins/
 
   cp <pluign> /usr/lib/munin/plugins/
 
   ln -s /usr/lib/munin/plugins/<plugin> /etc/munin/plugins/<plugin>
 
   ln -s /usr/lib/munin/plugins/<plugin> /etc/munin/plugins/<plugin>
 +
  /etc/rc.d/munin-node restart
 +
  (Then refresh the web page, there should be no need to restart munin-master)

Revision as of 22:24, 1 November 2009

"Munin the monitoring tool surveys all your computers and remembers what it saw. It presents all the information in graphs through a web interface. Its emphasis is on plug and play capabilities. After completing a installation a high number of monitoring plugins will be playing with no more effort.

Using Munin you can easily monitor the performance of your computers, networks, SANs, applications, weather measurements and whatever comes to mind. It makes it easy to determine "what's different today" when a performance problem crops up. It makes it easy to see how you're doing capacity-wise on any resources.

Munin uses the excellent RRDTool (written by Tobi Oetiker) and the framework is written in Perl, while plugins may be written in any language. Munin has a master/node architecture in which the master connects to all the nodes at regular intervals and asks them for data. It then stores the data in RRD files, and (if needed) updates the graphs. One of the main goals has been ease of creating new plugins (graphs). " Munin

Simply put, munin allows you to make graphs about system statistics. See a running munin example

Installation

Munin relies on a client-server model. The client is munin-node, and the server is munin (refered to "munin-master" in the documentation). You must have munin-node and munin-master installed for this installation to work.

You will only need to install munin-master on a single machine. But munin-node will need to be installed on all machines you wish to monitor. This article will focus on a single machine installation. Further documentation may be found on the munin documentation wiki.

The following guide sets up a munin under a directory beneath the html root.

Dependencies

Munin requires the following packages:

# pacman -S apache php php-apache

Add an entry to your rc.conf:

 DAEMONS=(syslog-ng network netfs crond httpd)

Edit /etc/hosts.allow by adding the following line:

httpd: ALL

Optional sanity check

Start the webserver:

# /etc/rc.d/httpd start

Create a test document:

# echo "Testing httpd" > /srv/http/index.html

Open a web browser and access http://127.0.0.1/ -- you should see the test document.

If it did not work try the following and check again:

# chown -R http:http /var/run/httpd/

Finally, stop the webserver:

# /etc/rc.d/httpd stop

Apache Notes

The html root is located under /srv/http. This directory may not be created by default, so create it if not present:

# mkdir -p /srv/http

Apache also creates (or uses) the user account and group of http:http. Make sure apache has permissions on these directories:

# chown http:http /srv/http

All of these settings can be changed in the /etc/httpd/conf/httpd.conf.

Installing Munin

Currently there's a munin package in the AUR, and a munin-node package in extra. Installing with yaourt is a great choice:

$ yaourt -S munin munin-node

Now check /srv/http. There should be a munin directory.

Configuration

Add the daemon to /etc/rc.conf:

DAEMONS=(syslog-ng network netfs crond httpd munin-node)

Optional: Run the following to have munin update every 5 minutes:

# crontab /etc/munin/munin-cron-entry -u munin

Testing the Installation

Start the services:

#/etc/rc.d/httpd start
#/etc/rc.d/munin-node start

Then test the interface by pointing your browser to http://localhost/munin

Note: It might take a while for the graphs to have data, so be patient. Wait about 30 minutes to an hour.

Plugins

There are many munin plugins (and they're easy to write). You can start looking for plugins on the munin exchange.

Basically all plugins are installed in the following manner (although there are exceptions, review each plugin!):

  (This is on each system running munin-node)
  cp <pluign> /usr/lib/munin/plugins/
  ln -s /usr/lib/munin/plugins/<plugin> /etc/munin/plugins/<plugin>
  /etc/rc.d/munin-node restart
  (Then refresh the web page, there should be no need to restart munin-master)