nagios_plugins

This custom nagios plugins/checks are tested and working with Nagios, but are also compatible with Icinga and Sensu to the best of my experience. Instructions here are specific for nagios/icinga1 but the setting changes for icinga2/sensu are probably trivial.

All the checks are provided under the provided GPL license. Feel free to fork, contribute and improve.

Custom nagios plugins

• check_apt_updates

Checks for pending upgradable packages using apt. Returns warning when "soft" (i.e. non-security) upgradable packages are available, and critical when any "critical" upgrade is available (i.e in the security repositories).

Accepts a parameter (-c) to watch only for critical updates.

Only works for local (must be called through nrpe) and requires the system to perform apt-get update on its own (the check doesn't update apt available list since it would require root privileges)

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• check_foo

Silly check that will return an OK value by default, or else the return value passed as parameter. It was useful for making nagios "pseudo-hosts" where I wanted to associate checks which are service and not host based, defining a new host and setting check_foo as the alive check command so that it appears always as up.

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• check_graphite_metric

Check metrics provided by a graphite installation. Useful if you have a running graphite monitoring system in place and want to set alerts through nagios without duplication of scripts running locally, and setting nrpe or ssh checks.

Requires running graphite. Allows https interfaces with user authentication. Allows lo/hi thresholds for alerts. Allows for hysteresis margins.

Check command help for more details on usage.

Set a service check similar to this:

define command{
        command_name    check_graphite_metric
        command_line    $USER1$/check_graphite_metric -H $HOSTNAME$ $ARG1$
}

define service{
	use			generic-service
	service_description	your_check
	check_command		check_graphite_metric!-W TH_W_HI -C TH_C_HI -w TH_W_LO -c TH_C_LO -m '%HOST%.your.metric.name'
}

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• check_smart_status.sh

Checks S.M.A.R.T. status on ATA drives. It will run auto-detection of available drives through smartd onecheck command and smartctl --scan, thus removing the need to provide a list of installed drives and simplifying the checks. Since smartmontools are root-only tools, you will need to add a sudoers entry for the script or the smartd/smartctl binaries to your monitoring user.

So far this check monitors known bad sector SMART attributes (197/198) and bad status from self tests, plus smartctl return codes for completely dead drives.

You will need to schedule the SMART self-tests on a regular basis, typically by setting up and starting smartd service, or via a crontab.

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Custom nagios notifications

• notify_by_email_html.sh

Send notifications in html format, with extended information. If service and of graphite_metric kind, then include the graphite image and links to wider time frames for extra information, as well as links to nagios reports and acknowledge functions. For non-grahite and host checks include nagios' trend native graph of status history. Defaults to service notifications if -t not provided. Requires nagios to pass environment variables to scripts, by setting enable_environment_macros=1 on nagios.cfg

Set the notification like:

define command{
        command_name    notify-service-by-email
        command_line    $USER1$/notify_by_email_html.sh $CONTACTEMAIL$ -t [host|service]
}