Saiweb

Pre-req reading:

Nagios customization: Alerting via SMS, or anything you like!

Making the bird tweet using python

or
Update twitter in a single line

This entry will cover how to send nagios alerts to twitter, in the examples to follow curl will be used however you can choose to use the python example (link above) in place of this.

Firstly edit /usr/local/nagios/etc/objects/commands.cfg

And add the two following commands.

UPDATE 24/03/2011 Twitter no longer supports basic auth, use my oAuth updater here

Now define a contact for this twitter service

/usr/local/nagios/etc/objects/contacts.cfg

Choose your own notification options, for my feed I only choose alerts, I also have this send updated to a ‘private feed’ which I then follow.

Add this contact into your existing contact groups, i.e.

Then run a nagios-verify to ensure you have no syntax errors, and restart nagios.

Trigger an alert by manually switching a monitored service off or entering a manual result to test.

Tweet

So I find myself needing to tweak my Nagios installation a little bit, in this case I found the need for “out of hours” SMS alerts.

Nagios doesn’t cater for this natively, rather it does however allow you to create your own custom commands, this allows you to specify a script to be executed.

Now I am going to assume you are already quite familiar with Nagios , so here is the command definition from my installation.

# ‘alert-by-sms’ command definition
define command{
command_name alert-by-sms
command_line /etc/nagios/alert-by-sms.php “** $NOTIFICATIONTYPE$ alert – $HOSTALIAS$/$SERVICEDESC$ is $SERVICESTATE$ **”
}

As you can see all this command definition realy does is execute a php script, bear in mind that

“/path/to/php /path/to/script ”

as the command_line does not seem to work, so just add “#!/path/to/php -q” to the top of the php script (before the opening <?PHP tag). and CHMOD +X the file.

The php script used here takes $argv[1] and passes it into a function specific to the SMS api I use, the phone number and API definitions are hard coded ito the script.
You don’t really need me to upload my script, and if you do then you shouldn’t be attempting this …

Basically Nagios will execute the script, as defined at command_line, the script can do anything you choose.

Now to implement the command so it is actually used, I am pretty sure this entry in “timeperiods.cfg” is the default but just incase here it is.

# ‘nonworkhours’ timeperiod definition
define timeperiod{
timeperiod_name nonworkhours
alias Non-Work Hours
sunday 00:00-24:00
monday 00:00-09:00,17:00-24:00
tuesday 00:00-09:00,17:00-24:00
wednesday 00:00-09:00,17:00-24:00
thursday 00:00-09:00,17:00-24:00
friday 00:00-09:00,17:00-24:00
saturday 00:00-24:00
}

This is what I use for the “out of hours” definition, now to implement the SMS alerting, for this I have simply created a new contact definition in “contacts.cfg”, granted this means there are now two contact definitions for myself.

define contact{
contact_name out_of_hours
alias Out Of Hours Mobile

service_notification_period nonworkhours
host_notification_period nonworkhours
service_notification_options c,u,r,f
host_notification_options d,u,r
service_notification_commands alert-by-sms
host_notification_commands alert-by-sms
email HIDDEN EMAIL

}

This can be further customized depending on your setup, in this case the contact is me and I want to receive alerts for all servers & services, so I just add the contact “out_of_hours” into the admins contact group.

define contactgroup{
contactgroup_name admins
alias Nagios Administrators
members nagios-admin,out_of_hours
}

So there you have it, you now have the ground work to potentially make Nagios fire you alerts anyway you like, you could go as far as having it call you via attached modem, if you _realy_ want, but when you want your servers talking to you via phone call is the day you need to switch to decaff, and head out to the pub once in a while.

Now just “nagios -v /path/to/nagios.cfg” to do a quick sanity check and make sure there are no errors (if you have any go back and fix them and run nagios -v again!), if all is ok /etc/init.d/nagios restart (or equivalent for your distribution).

As always if you run into problems drop me a comment Tweet