Tuesday, October 27, 2009

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


    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.


- 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!

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