Re: munin node proxy?

Nicolai Langfeldt wrote:
> S. Banerian wrote:
>> I have used munin for a while now, and find it useful.  I have found a
>> need for a way to avoid use of snmp to monitor some devices on a
>> protected subnet, and am wondering if there is some way to 'proxy'
>> requests from a munin server out in the world, to munin-nodes that are
>> in a private subnet.
>>
>> The topology would be analogous to what is done with snmp plugins.
>>
>> Public            "gateway"        private
>>
>> munin-server -->  munin-proxy ---> munin-node #1
>>                      |-----------> munin-node #2
>>                      |-----------> munin-node #3
> 
> I've thought of this (http://munin.projects.linpro.no/ticket/424), but
> I'm far from implementing it myself.  When I think of it now I think it
> should be sort of easy.
> 
> Envision a wildcard plugin called proxy_ which could be symlinked as
> proxy_foo.example.com_df to get df from foo.example.com.  It will have
> to supply a hostname header for "config" requests and otherwise re-play,
> more or less, what the munin node at foo.example.com says.  It might
> even be doable with shell-script and the help of netcat.  Very very roughly:
> 
> # Do whatever to pick out the wildcard arguments.
> 
> replay() {
>   (echo "$3"; echo quit) | nc $1 $2
> }
> 
> case $1 in
>   config) echo hostname $hostname
>           replay $hostname 4949 "config $plugin";;
>   '')     replay $hostname 4949 "fetch $plugin";;
> esac
> 
> 
> You might need to apply some sed or some such to remove stuff from nc
> that is not wanted.
> 
> I would be very happy indeed if someone took the trouble to get this
> working.
> 
> Nicolai


something like this does work, in terms of grabbing the data and passing
off to the server (no wordwrap intended in replay() ):

#!/bin/sh

replay() {
  (echo "$3"; echo quit) | nc $1 $2  | grep -v "munin node at $1" | grep
-v "^\."
}

nameplug=`basename $0 | sed 's/^proxy_//'`
hostname=` echo $nameplug | sed 's/\_.*//g'`
plugin=` echo $nameplug | sed 's/.*\_//g'`

case $1 in
        config)
                echo host_name $hostname
                replay $hostname 4949 "config $plugin";;
        '')
                replay $hostname 4949 "fetch $plugin";;
esac


eg.
ln -s /usr/share/munin/plugins/proxy__ ./proxy_my.domain.com_df

however, I've not determined how to set up a separate (set of) 'nodes'
on the munin server, as I've been able to with the snmp__if_ plugins.

using
[my.domain.com]
 address 123.456.789.123
 use_node_name no

does not do, as for the snmp plugins.


-- 
S. Banerian
206-598-0302
UWMC Radiation Oncology


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