[repost] OpenWRT on a TP-Link 1043ND: running munin-lite

05 May 2011

Disclaimer: This post was on my old blog. I noticed 404s from people coming from another blog that linked to this post. Although I'm not using OpenWRT anymore I've decided to put the original back online for those who end up here.

Original article:

My noisy Pentium 3 Vyatta machine is done. Its duties are now taken care of by a TP-Link 1043ND, flashed with OpenWRT version 10.03.1-rc4. Saving 40W and lots of dB it is a nice replacement.

Having running a Munin master on my home server, I wanted to include statistics from my newly installed router. This was simply done by

opkg update
opkg install muninlite

From that moment on I received a mail from cron: something is wrong with muninlite on OpenWRT. Errors like

2011/05/05 22:00:07 [WARNING] munin_set_var_loc: Setting unknown option '_usr_sbin_munin_node_' at myhost.com;openwrt.myhost.com:if_eth0

Digging through the code (which is easy, as muninlite is just a shell script) I determined it was 'ethtool' which could not be found.

opkg install ethtool

Sure, that worked. But now another error appeared. You can check this by running 'ethtool eth0' manually:

Settings for eth0:
Cannot get device settings: No such device
    Current message level: 0x000000ff (255)
        drv probe link timer ifdown ifup rx_err tx_err
    Link detected: yes

To be honoust, I'm not sure how to fix that. But I do know how to work around it. Find the line in /usr/sbin/munin-node where 'ethtool' is executed. You'll see it is an if-statement, a total of 4 lines. Comment them out using #-signs, and your inbox is free of the annoying error messages.

Not the best solution, but regarding the fact you'll only 'miss' the maximum up and down from you ethernet interfaces I can't give a rat's buttocks.