Useful scripts for Nagios

Send alert to AOL instant messenger users (AIM)
Check LDAP servers
Check network connectivity using traceroute

These are some of my homebrew scripts that I use with Nagios.

1. Send alerts to AOL instant messenger users (AIM)

a) You will need to download and install the Net::AIMTOC Perl module from CPAN
b) Download following script send_aim_msg.txt. Save it as send_aim_msg.pl in e.g. /etc/nagios, make sure it has executable permissions.
c) Look in the file and adjust the $robotuser and $robotpassword variables
d) Add following to /etc/nagios/misccommands.cfg

define command{
 command_name notify-by-im
 command_line echo "Service: $SERVICEDESC$ Host: $HOSTNAME Address:\ $HOSTADDRESS State: $SERVICESTATE Info: $SERVICEOUTPUT Date: $LONGDATETIME$" \ | /etc/nagios/send_aim_msg.pl <sysadminnicks>
 }

define command{
 command_name host-notify-by-im
 command_line /usr/bin/printf "%b" "Host '$HOSTALIAS$' is $HOSTSTATE$ Info:\ $HOSTOUTPUT$ Time: $LONGDATETIME$" | /etc/nagios/send_aim_msg.pl <sysadminnicks>
 }

Put all sysadminnicks you want to instant message

e) Then just add notify-by-im and host-notify-by-im to

define contact{
        contact_name                    vuksan
        alias                           Vladimir Vuksan
        service_notification_period     24x7
        host_notification_period        24x7
        service_notification_options    w,u,c,r
        host_notification_options       d,r
        service_notification_commands   notify-by-email,notify-by-im
        host_notification_commands      host-notify-by-email,host-notify-by-im
        email                           vuksan@domain.commer
        }

f) Don't forget to check the Nagios syntax with /usr/sbin/nagios -v /etc/nagios/nagios.cfg

2. Check LDAP

I was not happy with the check_ldap script that comes with Nagios so I took the ldap.monitor from Mon which is monitoring facility somewhat similar to Nagios (not as powerful).

a) Download check_ldap. Rename it to e.g. check_ldap and stick it in /usr/libexec/. Make sure you it has execute permissions and that nagios user can execute it

b) Add following to checkcommands.cfg

# Check LDAP
define command{
        command_name    check_ldap
        command_line    $USER1$/check_ldap $HOSTADDRESS$ -base="dc=domain,dc=com" \ -filter="uid=vuksan" -attribute=uid -value=vuksan
        }

Modify the entries in red. Basically what the script does is connects to LDAP server filters based on uid=vuksan and makes sure that attribute uid has value of vuksan.

c) Attach check_ldap command to a service

3. Check host connectivity using traceroute

On occasion hosts that may not pingable through ICMP may be "pingable" through traceroute because as man traceroute says

Traceroute utilizes the IP protocol ‘time to live’ field and attempts to elicit an ICMP TIME_EXCEEDED response from each gateway along the path to some host.

I wrote a script to utilize that fact.

a) Download check_traceroute. Stick it in /usr/libexec/. Make sure you it has execute permissions and that nagios user can execute it
b) Add following to checkcommands.cfg

define command{
        command_name    check_traceroute
        command_line    $USER1$/check_traceroute $HOSTADDRESS$
        }

c) Attach check_traceroute command to a service

Author: Vladimir Vuksan E-mail me