Config file parsing26 May 2010
I've been setting up some new VMs for a separate project at work. I've realized that this is painful for two reasons: Bacula and Nagios.
Both are important...can't have a service without monitoring, and can't have a machine without backups. But each of these are configured by vast files; Bacula's is monolithic (the director's, anyhow, which is where you add new jobs) and Nagios' is legion. And they're hard to configure automagically with sed/awk/perl or cfengine; their stanzas span lines, and whitespace is important.
I've recently added a short script to my Nagios config; it regenerates a file that monitors all the Bacula jobs and makes sure they happen often enough. This is good...and I want more.
I found pynag, a Python module to parse and configure Nagios files. This is a start. I've had problems getting its head around my config files, because it didn't understand recursion in hostgroups (which I think is a recent feature of Nagios) or a hostname equal to "*". I've got the first working, and I'm banging my head against the second. The three books I got recently on Python should help (wow, IronPython looks nice).
There are a lot of example scripts with pynag. None do exactly what I want, but it looks like it should be possible to generate Nagios config files from some kind of list of hosts and services. This would be a big improvement.
But then there's Augeas, which does bi-directional parsing of config files. Have a look at the walk-through...it's pretty astounding. I realized that I've been looking for something like this for a long time: an easier way of managing all sorts of config files. Cfengine (v2 to be sure) just isn't cutting it anymore for me.
Now, the problem with Augeas for my present task is that there isn't anything in the current tree that does what I want, either. There is a commit for parsing nagios.cfg -- not sure if it's been released, or if it will parse everything in a Nagios config_dir. There's nothing for Bacula, either. This will mean a lot more work to get my ideal configuration management tool.
(On a side note, my wife said something to me the other day that was quite striking: I need tasks that can be divvied up into 45-minute chunks. That's how much free time I've got in the morning, bus rides to and from work, and the evening. Commute + kids != long blocks of free time.)
And I've got a congenital weakness for grand overarching syntheses of all existing knowledge...or at least big tasks like managing config files. So I'm trying to be aware of my brain.
...and there's son #2 waking up. Time to post.