Monitoring Servers and Clients using Munin in Ubuntu
It uses the excellent RRDTool and is written in Perl. Munin has a master/node architecture in which the master connects to all the nodes at regular intervals and asks them for sdata. 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).
Preparing Your System
You need to install apache web server using the following command
sudo apt-get install apache2
Munin contains two parts for it's configuration
munin (munin server) -- the part that creates the monitoring graphs
munin-node (munin Client) -- the munin client program.
Install Munin Server and client in Ubuntu
If you want to install munin server and munin client you need to install munin and munin-node packages using the following command
sudo apt-get install munin munin-node
Munin File Structure
This will install munin in /etc/munin directory this includes the following files
munin.conf munin-node.conf plugin-conf.d plugins templates
This will install files for webserver root directory in /var/www/munin directory this includes the following files
definitions.html index.html localdomain logo.png style.css
If you want to configure munin server you need to edit the /etc/munin/munin.conf file.The sample file looks like below.
sudo vi /etc/munin/munin.conf
# Example configuration file for Munin, generated by ‘make build'
# The next three variables specifies where the location of the RRD
# databases, the HTML output, and the logs, severally. They all
# must be writable by the user running munin-cron.
# Where to look for the HTML templates
# Make graphs show values per minute instead of per second
# Drop [email protected] and [email protected] an email everytime
# something changes (OK -> WARNING, CRITICAL -> OK, etc)
#contact.someuser.command mail -s "Munin notification" [email protected]
#contact.anotheruser.command mail -s "Munin notification" [email protected]
# For those with Nagios, the following might come in handy. In addition,
# the services must be defined in the Nagios server as well.
#contact.nagios.command /usr/sbin/send_nsca -H nagios.host.com -c /etc/send_nsca.cfg
# a simple host tree
-End File --
In this above sample config file we need to look maily these files
If you want to change any of the paths you need to change here.The one thing you might want to change is htmldir option
where you can change for you clients name or any other name suitable for you
Most Important thing is adding clients machines to munin.conf file for this you can see by default
localhost.localdomain is added under a simple host tree that looks like this
# a simple host tree
Now server side configuration ready.Now we are going see munin clients configuration
Munin Clients Configuration in Ubuntu
If you want to monitor any number of client machines using munin you need to install munin-node package in all your clients machines
Installing munin Client in Ubuntu
If you want to install munin client in your machine you need to enter the following command
sudo apt-get install munin-node
This will install munin node package and it will create a folder called /etc/munin.
Munin-node File Structure
this contains the following files
munin-node.conf plugin-conf.d plugins
munin-node.conf -- Client Configuration File
plugin-conf.d -- Configuration of plugins for this node
plugins -- A directory in which each file is a symlink to a real plugin in /usr/share/munin/plugins
Configuring Munin Node
Now you need to configure the munin-node.conf file
Configuration file looks like this and in this file i have entered some examples also
-- start file --
# Example config-file for munin-node
# Which port to bind to;
# Regexps for files to ignore
# Set this if the client doesn't report the correct hostname when
# telnetting to localhost, port 4949
# A list of addresses that are allowed to connect. This must be a
# regular expression, due to brain damage in Net::Server, which
# doesn't understand CIDR-style network notation. You may repeat
# the allow line as many times as you'd like
In the above configuration file there are two important things you need to enter first one is under
#host_name localhost.localdomain you need to add your client machine fully qualified name example
Second one is you need to enter the server ipaddress by defauly you can see 127.0.0.1 in your config file under that
you need to add your munin server ipaddress example as follows
-- End File --
Adding Munin Plugins
If you want to install munin plugins you need to check the available plugins from here
Now you need to add plugins for for your client machine to monitor the required services for this edit the file located
at /etc/munin/plugin-conf.d/munin-node sample file looks like below
-- Start File --
# This file is used to configure how the plugins are invoked.
# user # Set the user to run the plugin as.
# group # Set the group to run the plugin as.
# command # Run instead of the plugin. %c expands to
# what would normally be run.
# env. # Sets in the plugin's environment, see the
# individual plugins to find out which variables they
# care about.
-- End File --
Now you need to add the user,group,command,env. and plugin name
Now look in to plugins/ directory it is a directory in which each file is a symlink to a real plugin in /usr/share/munin/plugins.Any plugin linked in here will be checked for and displayed in the resulting web pages.Add the plugins you want (e.g. if running exim4 then I'd add postfix_queue and postfix_stats).You'll need to set user/group rights in the munin-node conf file.
Most plugins can be run from the command line with the autoconf param to check if they can run -- e.g.
./postfix_stats autoconf yes
You can add any plugins you want to monitor and default plugins are located at /etc/munin/plugins directory
Finally you need to restart your munin service for your client machine after configuring any plugins
sudo /etc/init.d/munin-node restart
That's it from client side configuration
Finally important step you need to do in your munin server config file that is located in your munin server machine
You need to add all your client machines list under this
# a simple host tree
# a simple host tree
[munintest.test.com] -- this is our test client we have mentioned earlier
After entering all the client machine details you need to the following command to take the effect of our new changes effect.
sudo /usr/share/munin/munin-update --force-root
Testing Your Munin Installation
Now you need to go to http://your-server-ip/munin/ you should see the following screen if you have more no.of clients it should show those clients also
Once you click on Localdomain (which means localhost) you should see the following screen with list of currently monitoring graphs
If you want to see the graphs you need to wait for some time this is automaticalling done by munin.Munin sets up a cron job via the file /etc/cron.d/munin which will run /usr/bin/munin-cron.Running this file will poll each of the nodes -- and then will create the graphs in /var/www/html
Keeping an eye on these graphs will help you to keep your servers running healthily -- and can give advance warning of problems to come.
If you want to protect munin output directory (default /var/www/munin) you can use htaccess file for this and give access only for required users
If you have any problems you need to check the log files of munin located at /var/log/munin directory
On server side Important log files are
munin-node.log -- should show the connections that are occuring.
munin-graph.log -- should show info on the services being graphed.
munin-html.log -- should show info on the html being generated.
On Client side important log files are
munin-node.log -- should show the connections that are occuring
Munin Sample Graphs
Here is the some of the sample Graphs i have got from my server machine these graphs are for one day it will show by weekly,by monthly and by Yearly Graphs also
CPU Usage -- By Day
Load Average -- By Day
Memory Usage -- By Day
No.Of Processes Running -- By Day