Hi,

I just read your (old) blog post about monitoring the temperature of the Raspberry Pi with munin[1].

I had the exact same error as you did when I was trying to let munin do the job all by himself:

temp.value VCHI initialization failed)

It turns out the solution was quite easy: in

/etc/munin/plugin-conf.d/munin-node

You simply need to tell munin that it needs to run as root for this specific plugin:

[pisense_]

user root

(the plugins also tracks clock speeds and voltages but any other will work just fine as long as the “user root” is set in the munin-node plugin config file : [2]). Probably the easiest way to check if it’s working is to use munin-run command before and after the change.

“Demo”: [3]

By the way, “Connect different LANs over openVPN” is pretty tempting, I always wondered what the performances would be like through a USB-to-ethernet adapter.

Have a nice one !

Apteno

[1] https://yeri.be/munin-raspberry-pi-temperature [2] https://github.com/perception101/pisense/blob/master/pisense_ [3] http://ronon.jefter.com/jefter.com/adama.jefter.com/index.html#sensors

And indeed, I knew it was a permission issue, but instead of running this script as root, I tried adding Munin to a group that was supposed to be able to run  vcgencmd (which didn’t work out).

But, let’s look at a simpler solution:

1. Go to /etc/munin/plugins and create a file temp with this content (and some indentation yourself):

   #!/bin/sh
   case $1 in
   config)
   cat <<'EOM'
   graph_category system
   graph_title Temperature
   graph_vlabel temp
   temp.label Celsius
   EOM
   exit 0;;
   esac
   echo -n "temp.value "
   /opt/vc/bin/vcgencmd measure_temp | cut -d "=" -f2 | cut -d "'" -f1

2. As you noticed, this doesn't require any more scripts to run from cron (and thus, in case you used my previous script, remove it from cron)

3. chmod +x temp

4. Make sure it runs as root; in /etc/munin/plugin-conf.d create the file temp.conf with this content:

   [temp]
   user root

5. Test it:

   # munin-run temp
   temp.value 59.5

Tadaaaa. Simpler.

Thanks Anthony :)

Create /usr/local/bin/getVpnUsers.sh:

#!/bin/bash
echo "VPN.value `cat /var/log/openvpn-status.log | sed -e '1,/Common Name/d' | 
sed -e '/ROUTING TABLE/,$d' | wc -l`" > /tmp/.vpn_munin.txt

You can change the name of VPN.value to the VPN name and/or add multiple lines (each with a different NAME.value if you’re running more than one VPN user. Be sure to cat the right log file).

And:

chmod +x /usr/local/bin/getVpnUsers.sh

Add this to root cron:

*/5 * * * * /usr/local/bin/getVpnUsers.sh >/dev/null 2>&1

Now create /etc/munin/plugins/vpnusers:

#!/bin/sh

case $1 in
 config)
 cat <<'EOM'
graph_category network
graph_title oVPN users
graph_vlabel users
VPN.label My oVPN
# add more labels like this:
#isazi.label Isazi VPN
EOM
 exit 0;;
esac

cat /tmp/.vpn_munin.txt

And:

chmod +x /etc/munin/plugins/vpnusers

You’ll need the correct NAME.label in the plugin depending on the name you choose in part one.

And restart munin-node:

/etc/init.d/munin-node restart

That’s it.

Check your Munin under “network”. It might take ~15+ minutes before the graph is generated.

First of all, install Munin and make sure it’s working.

Then follow these steps:

1. We’ll use cron to write the current temp to a log file. We do this because I wasn’t able to get Munin to directly execute the command (error: temp.value VCHI initialization failed)

Execute crontab -e and add this line (this has to be on one line):

*/5 * * * * /opt/vc/bin/vcgencmd measure_temp | cut -d “=” -f2 | cut -d “’” -f1 > /tmp/.temp

2. Go to /etc/munin/plugins/, and create a file temp, and add this content:

#!/bin/sh case $1 in config) cat <<‘EOM’ graph_category system graph_title Temperature graph_vlabel temp temp.label Celsius EOM exit 0;; esac echo -n “temp.value " cat /tmp/.temp

Save and exit the editor.

I’m not sure this is needed, but better do it: chmod +x temp

3. restart munin-node (/etc/init.d/munin-node restart)

4. test if it’s working:

# telnet localhost 4949 Trying 127.0.0.1… Connected to localhost. Escape character is ‘^]’.

fetch temp temp.value 57.3 .

That’s it. Your munin daemon/host should now correctly graph the temperature.

Edit (8/2/2014): updated script can be found here.