Tag Archives: eth0

E-mail alerts from munin for network bandwidth usage

I’m a big fan of munin for monitoring your linux server. It’s quick and easy to install and produces some nice graphs.

I run some OpenVZ servers and wanted to get munin to alert me if there was a sudden spike in my bandwidth throughput.

There are some instructions here for setting up alerts from munin but I couldn’t get it to work for the “if_” plugin that is used to generate the bandwidth graphs.

Turns out that plugin doesn’t produce warnings as standard. Here’s a quick and easy solution that works for me (although there are some pitfalls – such as the fact that you’re setting a generic setting for all interfaces)

On the machine running ‘munin-node’ edit the file /usr/share/munin/plugins/if_   (the location may vary)

and add this line with all the other echo statements –

echo "up.warning 1000000"

It’s in bits per second so that should set it to 1MB/s

Now on the machine running ‘munin’ (could be the same machine) edit the file /etc/munin/munin.conf and somewhere near the top add the lines –

contacts me
contact.me.command mail -s "Munin notification ${var:host}" user@example.com
contact.me.always_send warning

And that should be it. Give it 5 minutes and see if you get an alert  (might be worth setting the warning level to less than 1MB/s to test!)