The Nagios light-bar

David Sterndavid.stern@jhuapl.edu

What is it?

Why do we need it?

DoD work requires air-gapped networks

How would you know if a service is down if you’re not on the network?

The Hardware

An unobstructed View

Backside of base unit: connection to light-bar

Equipment network discovery program

Initial connection requires crossover cable

Base unit generates a webpage

The Settings tab allows you to configure the device

You need to identify the type of device

Security settings

Optional settings

The network MUST be active before you power-on the unit

It might be a smart idea to set the light-bar for DHCP address

It would be a smart idea to monitor that the light-bar is available

If I can control the light-bar from the web, why not use WGET

The Secret Sauce; undocumented

http://light-bar/cmd.cgi\?action=ST\&t=A2\&a=1 makes the light-bar go beep

http://light-bar/cmd.cgi\?action=ST\&t=A2\&a=0 turns off the noise

http://light-bar/cmd.cgi\?action=ST\&t=GR\&a=1 makes the green light go on

http://light-bar/cmd.cgi\?action=ST\&t=GR\&a=0 turns off the green light

Substitute OR for GR to affect the orange(yellow) light

Substitute RE for GR to affect the red light

Getting nagios status

We can get the nagios status from the Service page:

http://nagios-server/nagios/cgi-bin/status\?host=all

Just search it for “serviceTotalsPROBLEMS”

N.B. You may need to insert authentication information in URL

http://nagiosadmin:nag-password@nagios-server/nagios/cgi-bin/status\?host=all

You can use the same format for the light-bar authentication

Mission Creep

How about if we get the light-bar to beep the first time a new alert occurs?

And since we don’t use nagios WARNING conditions, let’s use the yellow light to indicate unacknowledged alerts

Let’s put it all together…

This is NOT a plugin

Other cool things you can do with WGET

Hierarchical Nagios:A core nagios aware of other installs

What’s different on this nagios page?

Configuring “hierarchical” nagios

• Backup nagios before and after these changes• Install a Nagios server in each lab/sub-site• Edit side.{html,php}, Add stanza for each sub-

site and set refresh=300,• Tag each nagios sub-site: Main.{html,php} and

status.c status.cgi• Modify light-bar cron job to check each sub-

site, swap red,green dots as needed

One way to present the pages

Another way to present the data

The Results

Faster response time/higher uptime

Better awareness of our networks

Questions?