IPv6

This page documents the status and configuration of munin so that it can fetch data from nodes using IPv6.

Status

In svn source:trunk, munin Master and Node can communicate over IPv6.

In the source:branches/1.4-stable, munin Master cannot open an IPv6 socket, so cannot fetch node data over IPv6. If we backport r4332 to source:branches/1.4-stable, then Master will have the same capability as trunk. In source:branches/1.4-stable, munin Node can listen on IPv6 interfaces and IPv4 interfaces.

Bugs

To be filed

• wiki:munin-node.conf parser forces you to put an extra colon at the beginning of IPv6 addresses which start with colons, like ::1. See http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=523846#53

Configuration

munin node

• Ensure that you have installed Net::Server which supports IPv6. For example, the Debian package version 0.99-3 works (which is available in squeeze-backports if you run Debian Squeeze). Hopefully upstream Net::Server maintainers will integrate Debian's patch.
• Configure wiki:munin-node.conf to listen on an IPv6 socket. For example, "host *" or "host :::1" will work (the extra colon is due to a parsing bug to-be-filed).
• Ensure that sysctl net.ipv6.bindv6only = 0.

munin master

No special configuration necessary. If you're using a 1.4 version of munin, then you'll need to make the change in r4332 and have the IO::Socket::INET6 Perl module installed (packaged as libio-socket-inet6-perl in Debian).

To do

• Make sure "allow" works with IPv6 addresses in wiki:munin-node.conf.
• Backport r4332 to source:branches/1.4-stable?
• Make sure that master tries IPv4 if IPv6 connection attempt fails.

Workarounds for IPv6 on 1.4 munin-node

This is a workaround for you to get IPv6 munin-node on Debian stable/Ubuntu LTS with minimal effort.

The method involves putting a TCP proxy that supports IPv6 on hostname:4949, changing the munin-node listening port to 4948, and let the proxy forward connections to localhost:4948. You can use all sorts of proxies, a simple and available one is xinetd.

• change the munin-node port in /etc/munin/munin-node.conf to 4948. Restart the node and verify with telnet that you can connect to it on localhost.
• apt-get install xinetd
• put the example configuration into /etc/xinetd.d/munin, and remember to update the IPv6 allowed access range.
• Let your new and shiny 2.0 munin master poll the node over IPv6.

Example xinetd.conf entry for the port forwarder:

service munin
{
        port                    = 4949
        socket_type             = stream
        wait                    = no
        flags                   = ipv6
        user                    = nobody
        only_from               = 2001:db8::/32
        redirect                = 127.0.0.1 4948
}