Nagios exercise

PART I
-----------------------------------------------------------------------------

1. Install Nagios
   
    Do this as root.

    # apt-get install nagios2

    - You will be asked for a password for the nagios admin Web user
    - remember it!

    Now do this so that we can have pretty icons

    # apt-get install nagios-images


2. Create the Web user password file:

    # htpasswd -c /etc/nagios2/htpasswd.users nagiosadmin

New password:         
Re-type new password: 


2. You should already have a working Nagios!

    - Open a browser, and go to

    http://localhost/nagios2/

    - At the login prompt, login as:

        user: nagiosweb
        pass: 

3. Let's look at the interface together...

    # cd /etc/nagios2/

    # ls -l 
    -rw-r--r-- 1 root root    1598 2007-09-01 00:03 apache2.conf
    -rw-r--r-- 1 root root    9573 2006-12-20 22:20 cgi.cfg
    -rw-r--r-- 1 root root    4653 2006-12-20 22:20 commands.cfg
    drwxr-xr-x 2 root root    4096 2007-09-01 00:03 conf.d
    -rw-r--r-- 1 root root      26 2007-09-01 00:05 htpasswd.users
    -rw-r--r-- 1 root root   30431 2006-12-20 22:20 nagios.cfg
    -rw-r----- 1 root nagios  1293 2006-12-20 22:19 resource.cfg
    drwxr-xr-x 2 root root    4096 2006-12-20 22:20 stylesheets
    
    # ls -l conf.d/
    -rw-r--r-- 1 root root 1687 2006-12-20 22:19 contacts_nagios2.cfg
    -rw-r--r-- 1 root root  413 2006-12-20 22:19 extinfo_nagios2.cfg
    -rw-r--r-- 1 root root 1152 2006-12-20 22:19 generic-host_nagios2.cfg
    -rw-r--r-- 1 root root 1803 2006-12-20 22:19 generic-service_nagios2.cfg
    -rw-r--r-- 1 root root  210 2007-09-01 00:03 host-gateway_nagios2.cfg
    -rw-r--r-- 1 root root  976 2006-12-20 22:19 hostgroups_nagios2.cfg
    -rw-r--r-- 1 root root 2163 2006-12-20 22:19 localhost_nagios2.cfg
    -rw-r--r-- 1 root root  806 2006-12-20 22:19 services_nagios2.cfg
    -rw-r--r-- 1 root root 1609 2006-12-20 22:19 timeperiods_nagios2.cfg




PART II
-----------------------------------------------------------------------------

1. According to what we saw in class, let's add a new host

    - Pick any PC in the room, i.e. something other than pc10!

    # cd /etc/nagios2/conf.d/

    # vi pc10.cfg

define host {
    use         generic-host
    host_name   pc10
    alias       PC 10 at Apricot
    address     _______________       [pc10's IP address here]
}

    ... Save and quit

2. Let's create a new hostgroup for the occasion, and add our host
   to it

    - Edit the file hostgroups_nagios2.cfg and add a new group:

    # vi hostgroups_nagios2.cfg

define hostgroup {
    hostgroup_name  apricot-pcs
    alias           Apricot PCs
    members         pc10
}

3. Now let's associate some services to that host

    # vi services_nagios2.cfg

    - Find the section called "check that ssh services are running",
      and change the line:

hostgroup_name                  ssh-servers

    to

hostgroup_name                  ssh-servers, apricot-pcs



4. Verify that your configuration file is OK:

    # nagios2 -v /etc/nagios2/nagios.cfg 

    ... You should get :

Total Warnings: 0
Total Errors:   0

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


5. Reload Nagios

    # /etc/init.d/nagios2 reload


6. Go to the web interface (http://localhost/nagios2) and check the host
   you just added


7. Add ALL the PCs in the room!

    - Add all the PCs in the room to the config

    - Check HTTP for all PCs in the room

    - Remember to verify the configuration file!

    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 this without doing too much work!

8. Let's make a new plugin!

    - We'll do this together.