How to install Nagios 3 on Ubuntu 9.04

This manual is only covered how to install Nagios 3 on Ubuntu 9.04. Since the Nagios 3 is one of the Ubuntu package, so you can easily and quickly install Nagios 3 on Ubuntu system.

Assume you already install Ubuntu 9.04 OS, now we can start install Nagios 3 software:

• Install Nagios version 3
  
  
  # sudo apt-get install nagios3
  
  
  


• Create the web user password file after finished installation of Nagios 3
  
  
  # sudo htpasswd -c /etc/nagios3/htpasswd.users nagiosadmin
New password: xxxxxxxx
Re-type new password: xxxxxxxx
  
  
  


• Then you should already have a working Nagios!
  
  Open a browser, and go to http://localhost/nagios3/
  
  At the login prompt, login as:
  
  User: nagiosadmin
  Password: xxxxxxxx
  
  Note: There was a problem with gvfs, you will see the following error message:
  
  
  Nagios sent error message "DISK CRITIAL - /home/usr/.gvfs is not accessible:Permission denied"
  
  
  This problem is due to very special permissions set by fuse on the .gvfs directory. The workaround for this problem is here:
  
  >> modify /etc/nagios/conf.d/localhost_nagios2.cfg as follows:
  
  
  define command{
command_name check_all_disks_plus
command_line /usr/lib/nagios/plugins/check_disk -w $ARG1$ -c $ARG2$ -u GB -A -i .gvfs
}

define service{
use generic-service
host_name localhost
service_description Disk Space
check_command check_all_disks_plus!20%!10%
}

  
  Then run
  
  
  # sudo /etc/init.d/nagios3 restart
  
  
  


• If you would like to add a new host for monitoring, then you should add the configuration file for it.
  
  
  #cd /etc/nagios3/conf.d
#vi newhosts.cfg

define host{
use generic-host
host_name server1
alias server one at lab
address -------- [server1's IP address here]
}



• Let's create a new hostgroup for occasion, and add new hosts to it.
  
  Edit the file hostgroups_nagios2.cfg and add a new group:
  
  
  vi hostgroups_nagios2.cfg

define hostgroup{
hostgroup_name lab-servers
alias Lab Servers
members server1
}



• Now let's associate some services to that host
  
  
  # vi services_nagios2.cfg
  
  
  - find the section called "check that ping-only hosts are up", and change the line:
  
  
  hostgroup_name ping-servers
  
  
  to
  
  
  hostgroup_name ping-servers,lab-servers
  
  


• Verify that your configuration file is ok:
  
  
  # nagios3 -v /etc/nagios3/nagios.cfg
  
  
  ... You should get:
  
  
  Total warnings: 0
Total errors: 0

  
  
  Things look okay - No serious problems are detected during the check.
  


• Reload/Restart Nagios Services
  
  
  # /etc/init.d/nagios3 restart
  
  


• Go to the web intergace (http://localhost/nagios3) and check the host that you just added.
  
  Once the new host can be monitored from above URL, you are ready to add all your Servers/PCs/Routers/Network Equipments that would like to monitor.

NOTE:

- This requires a bit of planning, but you should have all the elements for doing this...
- Think well about the logical structure of the files - it should be possible for you to do without doing too much work!