And what’s best is you don’t have to jump through a bunch of hoops to get munin up and running. In this tutorial you will see how to get your Munin server up and running and monitoring your system and a sample client configuration that will monitor a client node. As you might expect, I will continue to build upon the Ubuntu Server series and install Munin on a Ubuntu 9.04 installation. NOTE: This same installation will work on Ubuntu 9.10 as well.Server installation/configuration

Installing Munin on the Ubunter server is simple. Open up a terminal window (or log into your server console) and issue the command:

sudo apt-get install munin

The above command will also install munin-node which is the client-side software. This is fine, so let it happen. Upon installation Munin will install the configuration files in /etc/munin, the executable in /etc/init.d/, and the web files in /var/www/munin.

The first thing that will need to be done is to configure your server correctly. Open up the /etc/munin/munin.conf file and look for this section:

dbdir     /var/lib/munin
htmldir    /var/www/munin/
logdir     /var/log/munin
rundir     /var/run/munin

Out of the box, this will work just fine.  But if you have any other needs that would dictate any of these directives change, change them here.

The next section to look for is this:

# a simple host tree
[localhost.localdomain]
address 127.0.0.1
use_node_name yes

What the above section does is monitor the server Munin is installed on. This configuration only needs to change if you have specific requirements. Also, if you need to add a client (node), this is where you add it.

In order to instruct Munin to monitor a remote machine you need to add a new host tree. Say, for instance, you want to monitor a machine on the IP addres 192.168.1.150. To do this you would add:

[MACHINE NAME]
address 192.168.1.150
use_node_name yes

Where MACHINE NAME is a name to indicate the job (or user, or department, etc) of the machine.

Once you have these configurations and save the file. Now to move on to the /etc/munin/munin-node.conf file. There is only one configuration you would need to add in order to monitor nodes. Look for this line:

allow ^127\.0\.0\.1$

Beneath this line you will want to add (in order to enable our new node):

allow ^192\.168\.1\.1$

Save this file and restart the Munin server with the command:

/etc/init.d/munin restart

Installing for client

All you need to do for your client is to install the munin-node package. To do this issue the command:

sudo apt-get install munin-node

On the client machine. Now start munin-node with the command:

sudo /etc/init.d/munin-node start

Munin will begin to monitor this client now.

The graphs

When all is up and running, point your browser to http://ADDRESS_TO_SERVER/munin/

Figure 1

Where ADDRESS_TO_SERVER is the actual address of the server. Very shortly after you install Munin you may only see a listing of the nodes being watched (see Figure 1). This is okay, it will take some time before data is actually collected.

After a while you will notice data collected and graphs developing. If you click on the localhost.localdomain link you will see data beginning to collect (see Figure 2).

Figure 2

Final thoughts

Munin is a very powerful tool that allows you to gather crucial data about your systems and networks. Now that you have Munin installed and running you can begin to extend the server by adding more and more clients as well as plugins. You will quickly find Munin to be a very valuable tool for data analysis on your various systems and networks.

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In this article you will see how to install Nagios on a working Ubuntu Server installation. The release I used was 9.04, but you should be able to use 8.04 just as easily.

Features

You want features? Nagios is full of them. Nagios can monitor your entire network, you can handle problem remediation, you can plan network downtime, you can watch hosts, systems, services, applications..there’s very little you can’t do with Nagios.

But let’s think about this installation. The best (and really only good) way to install Nagios is from source. This means you are going to have to do some compliation. Don’t worry, it’s not hard…when you have a step-by-step guide that is.

Before you start

If you are using, as I did, a Ubuntu server installation, you will need to install a few tools first. So from the command line (on your Ubuntu server) issue the following commands:

sudo apt-get install php5-gd

sudo apt-get install gcc

sudo apt-get install make

The above commands will install the tools you need in order to get Nagios installed. If you don’t install the above, you won’t be able to complete the installation.

Installing Nagios – preflight

Before you actually run the installation you will need to take care of some user/group accounting first.

Create the user nagios:

sudo useradd -m nagios

Give the nagios user a password:

sudo passwd nagios

NOTE: You will have to enter the new password twice for the above command.

Create the group nagios:
sudo groupadd nagios

Add the user nagios to the group nagios:

sudo usermod -G nagios nagios

Create the group nagcmd:

sudo groupadd nagcmd

Add the user nagios to the group nagcmd:

sudo usermod -a -G nagcmd nagios

Add the Apache user to the group nagcmd:

sudo usermod -a -G nagcmd www-data

Installing Nagios and Nagios Plugins

The first thing to do is to download the files you need. Issue the commands:

wget http://osdn.dl.sourceforge.net/sourceforge/nagios/nagios-3.0.6.tar.gz

and

wget http://osdn.dl.sourceforge.net/sourceforge/nagiosplug/nagios-
plugins-1.4.11.tar.gz

to download the files you need.

Untar the Nagios file with:

tar xvzf nagios-3.0.6.tar.gz

Change into the newly created Nagios directory with the command:

cd nagios-3.0.6

Now run the configure script using the nagcmd defined as the command group with the command:

sudo ./configure –with-command-group=nagcmd

Time to compile:

sudo make all

Time to install everything:

make install

make install-init

make install-config

make install-commandmode

Almost ready to finalize the installation of Nagios (before moving on to installing the plugins.) There is one simple configuration to take care of (for the basic installation). Open up the /usr/local/nagios/etc/objects/contacts.cfg file and add your email address as the contact email address. That’s the only configuration to change for now.

Configuring for the Web interface

There are just a few commands to run to configure the Web interface:

make install-webconf

htpasswd -c /usr/local/nagios/etc/htpasswd.users nagiosadmin

/etc/init.d/apache2 reload

The final command above simply restarts Apache.

Install the plugins

Before you log into your Nagios installation you have to install your plugins first. Change to the directory you downloaded the Nagios files to and untar the plugins file:

tar xvzf nagios-plugins-1.4.11.tar.gz

Now change into the newly created directory:

cd nagios-plugins-1.4.11

Compile the plugins with the command:

sudo ./configure –with-nagios-user=nagios –with-nagios-group=nagios

Now install the plugins with the following commands:

make

make install

Fire it up!

Of course you want to make sure Nagios starts any time the system is restarted. Do this with the command:

sudo ln -s /etc/init.d/nagios /etc/rcS.d/S99nagios

And finally, before you start up Nagios, make sure there are no errors with the command:

sudo /usr/local/nagios/bin/nagios -v /usr/local/nagios/etc/nagios.cfg

If you see no errors reported, it’s time to start it up. Issue the command:

sudo /etc/init.d/nagios start

Nagios is ready to go. Point your browser to:

http://ADDRESS_OF_NAGIOS_SERVER/nagios

You should be ready to enjoy all that is Nagios. Congratulations.

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