SITREP — Munin

You might be wondering where I disappeared given that I haven’t written for over a week. Knowing me it might have been bad, but luckily the situation is not that negative. I’m actually back in the States for a visit given I missed this year’s H1B lottery.

Now while I can’t figure out a permanent presence here, I’ve started working on a few tasks, including working with Munin to figure out the load on our current system. Thankfully, now that Munin is developed on Git, it’s dead easy to backport fixes, and to send new ones upstream. Indeed, the 2.0.2-r2 version that is in Gentoo is a little bit more stable and usable than the upstream-released one thanks to it. The one thing that I haven’t been able to work on yet as much as I want is supporting IPv6 nodes.

In particular, if you add a node to the Munin master using a hostname as address, and the hostname resolves as both A and AAAA, with version 2 it’ll try the IPv6 address and that will time out, because the node by default is only listening to IPv4 (on 0.0.0.0 — for whatever reason, the default config has an open listener and authorisation for localhost only, which usually is not what you want). For node IPv6 support, you need the new Net::Server for which an ebuild is present but it’s not (yet) in tree.

Now, in this new version I wired in a good support for the Java-based plugin — which is basically just a way to connect and monitor remote JMX support. The problem with this plugin is that it’s designed to monitor Tomcat and only Tomcat — and is not really wildcarded: you can choose between one of many possible plugin loggers, but they do not let you choose a custom value — this makes it hard for me to use since I want to monitor some custom data out of a Java app that uses JMX by default. So I guess I’ll soon be spending time working in Java, whooooo.

Still talking about Munin, you will probably soon have a new revision bump with an added syslog USE flag that adds a Log::Syslog dependency as well as setting up the configuration files to use syslog — I really dislike having too many files for logs around, especially when metalog is there for that.

I guess this is all for what concerns Munin, for now.