[colug-432] unix monitoring

[Paul Dubuc]

I've worked extensively with Nagios for over 5 years. I haven't found it to be 
brittle.  It's pretty reliable and stable.  It could be better, of course. 
There are features it doesn't have that I wish it did but, using some of the 
free add-ins that are available for it and doing some of my own scripting, 
I've been able to do quite a variety of monitoring functions with it.  It's 
pretty flexible, but it does take some effort to learn and use well.  Any 
flexible software tool seems to involve a greater level of effort to learn to 
use effectively.

I understand the complaints about Nagios configuration.  One thing that really 
helps is to make good use of templates and spread your configuration files out 
over a well thought out directory tree.  Nagios can be configured to walk the 
directory structure and read every file in it that has a .cfg suffix so 
there's no limit to the number of files you can use.  With a little planning 
you can have a configuration that's pretty easy to maintain with a text editor 
by putting things that rarely change, or that you want to be able to change 
globally, in template cfg files and putting the actual service/host 
definitions, which use the templates, elsewhere.  Most configuration changes I 
make are as easy as using vim to edit a file or two and do a global search and 
replace, or renaming a file so it doesn't end in .cfg to remove hosts and 
services from the configuration.  This may seem like common sense to some, but 
I've heard stories about shops where the Nagios configs are put in a single 
big file or a few of them with no use of templates.  Yeah, that makes 
configuration a pain and makes your monitoring system brittle.

While a GUI config utility would be nice for some changes, I tend to avoid 
them in favor of a well organized configuration schema.  With GUIs there 
always seems to be some things that are hard to do, or end up being much more 
repetitive than just using a text editor that you already know how to use.  So 
there's often a need to use the editor for things the GUI doesn't handle very 
well.  Then you run into the question of whether the GUI editor organizes your 
configuration files to be easily understood and modified in an editor.  Most 
GUI editors I've used give little thought to the human readability of the 
underlying files that they modify.

My $.02,
Paul Dubuc