Exercises: Nagios


1) Install Nagios:

#apt-get install nagios3

2) Set web admin password during the install process.

!Warning: current version of Nagios Ubuntu package seems to be broken -
you might have to create the web password manually, like so:

#sudo htpasswd -c /etc/nagios3/htpasswd.users nagiosadmin

3) Log on to http://localhost/nagios3 and verify your installation

4) Write a host definition, 
adding either a machine from our local network here, or one of your home servers.

Place it in a text file <somefilename>.cfg which you put either in

/etc/nagios3/conf.d

or in a directory which you have created yourself. 

(
If you do so, remember to tell Nagios so - by means of a 

cfg_dir=/etc/nagios3/<my_config_dir>

line in /etc/nagios3/nagios.cfg
)

5) Test your configuration changes by doing

#/usr/sbin/nagios3 -v /etc/nagios3/nagios.cfg

6) If no errors are found in your configuration, reload nagios to show your changes:

#/etc/init.d/nagios3 reload

Hopefully you can see your new host showing up and being ping checked.

7) Look into the existing service checks in

services_nagios2.cfg

Adapt what you are finding there and add a service check, e.g. http or ssh or smtp, to your newly added host.

8) Create a new hostgroup and add your newly added host to this group.

9) If no errors are found in your configuration, reload nagios to show your changes:

#/etc/init.d/nagios3 reload

Hopefully you can see your new hostgroup and service check showing up.