Agent-initiated Ping

[bytesize]

Hi guys,

I'm sure this is very simple but I can't get my head around it!

I have a Zabbix agent running on a server in Office A. I want this agent to ping a server in Office B, which are connected together by a VPN tunnel. If the remote server in Office B does not return a ping, then I know the VPN tunnel is down.

How do I configure this as a Ping check to run from the agent, instead of the monitoring server?

Thanks!

John

[Nate Bell]

You could write a script that runs on Computer A and pings Computer B. Set this script as a UserParameter in Computer A's zabbix_agentd.conf file, and add the item to your Zabbix server.

Of course, you're going to need to make the script do a bit more than just ping the second computer. It has to send out a ping, get some sort of response back even if the second computer can't be reached, and parse this information into data that Zabbix can handle.

Here's a simple script I wrote to do this, although I'm sure someone can come up with something better. This script takes an address as an argument, and sends a ping to that address. If some data is returned, then it sends a 1 to Zabbix, and if the address can't be pinged, it sends a 0.

#!/bin/bash
ping -c3 -W10 $1 &> /tmp/ping.dmp
grep received /tmp/ping.dmp | wc -l

Hope that helps, or at least gives you some ideas.

Nate

[bytesize]

Hi Nate,

Thanks for the post, that scripts work great!

It would be good to also collect the ICMP response times across the VPN, so I can see if the link is becoming really laggy; I dont suppose you could suggest an extention to your script which could do this?

I had a go myself, but I'm getting loads of "broken pipe" and timeout errors, even though the script runs fine from the command line!

Regards,

John

[Nate Bell]

That's actually a good idea. It gives a more descriptive output that way. I assume you were looking for the average response time for all the pings. If so, the script below will grab that data and report it (in ms). If the location you are trying to ping can not be pinged, it sends the value -1 to Zabbix, so you can easily set a trigger to go off.

#!/bin/bash
ping -c3 -W10 $1 &> /tmp/ping.dmp
status=$(grep received /tmp/ping.dmp | wc -l)
if [ $status -eq "0" ]; then
   echo -1
else
   grep avg /tmp/ping.dmp | cut -d" " -f4 | cut -d"/" -f2
fi

Nate

[bytesize]

Hmm, I'm still getting timeouts and "Broken Pipe" messages in the Zabbix agent log, even though the script is working fine from the command line when executed manually!

Here is what I have in my zabbix_agentd.conf:

UserParameter=vpn[officea-to-officeb],/usr/local/zabbix/scripts/ping-response.sh 192.168.1.1

...and then I have that parameter defined in the Zabbix server.

Any ideas what might be causing these errors? I'm executing the script on a Mac server, but seen as it works from the command line I don't understand why Zabbix can't execute it!

Thanks!

John

[bytesize]

Aha, found the answer... for some reason Zabbix doesn't like the wait time between pings in the script. If I reduce the timeout to 1 second, then its happy!

Here is the modified script (for mac users, note the flag has been changed for the wait time!)

#!/bin/bash
ping -c3 -i1 $1 &> /usr/local/zabbix/tmp/ping.dmp
status=$(grep received /usr/local/zabbix/tmp/ping.dmp | wc -l)
if [ $status -eq "0" ]; then
   echo -1
else
   grep avg /usr/local/zabbix/tmp/ping.dmp | cut -d" " -f4 | cut -d"/" -f2
fi

Thanks very much for the script though - works like a charm!

Does anybody know where to extend the timeout in Zabbix to enable pauses between pinging?

Regards,

John

[Nate Bell]

Blast! Beat me to it!
Glad you found your answer. You can increase the time Zabbix is willing to wait for an item in the zabbix_agentd.conf file. The default is 3 seconds. I can't remember if you have to change the same value in the zabbix_server.conf file, but I suspect you do.

As a side note, you might want to change your UserParameter syntax. If you change it to:

UserParameter=pingresponse[*],/usr/local/zabbix/scripts/ping-response.sh

and create an item like:

Description: VPN connection from computer A to B

Key: pingresponse[192.168.1.1]

then you can reuse the pingresponse UserParameter to ping other addresses with that machine. For instance, creating an item with a key:

 pingresponse[google.com]

will let that computer ping google.com. Easier than making a new UserParameter.

Nate

[bytesize]

Very, very efficient! Thanks Nate!

I will give this a little more testing and tweaking, then type it up in the cookbook forum as I bet others are also interested in a similar solution!

Thanks again!

John