Simon's Musings

March 15, 2008

New apacheconf and monitoring thoughts

Filed under: Uncategorized — sxw @ 5:05 pm
Tags: , ,

Yesterday, I shipped a new apacheconf component, with some significant changes to its monitoring support.

Apache is a complicated beast, with many different mechanisms for configuring it. Apacheconf doesn’t necessarily handle all of these different options, and sometimes work arounds are necessary. For example, apache supports providing multiple ip:port combinations to a VirtualHost directive. Apacheconf only supports providing one. For this reason, Neil had configured a service with two VirtualHosts, both with the same server name. Unfortunately, apacheconf assumed that all of the server names would be unique on a given hosts, and so builds its Nagios service descriptions (which must be unique) based on these server names. Upshot of this is that we end up with a monitoring configuration that won’t load.

I’ve made two changes to help mitigate this. Firstly, every apacheconf virtualhost now has a
vhostnagiosmonitor directive, which can be set to false to disable monitoring for that virtual host. Secondly, the apacheconf translator now keeps a list of all of the service descriptions it has created, and adds uniquifiers to any duplicates (initially the IP address and, if that isn’t sufficient, a number).

In addition to this, a new lcfg-monitor has shipped containing a number of bug fixes.

In the long run, we need to give lcfg-monitor the ability to take a list of machines and components for which monitoring is disabled – so that, if this happens again, we don’t end up having to rush to fix broken configurations, or components, just to keep monitoring running for everyone else.

1 Comment

  1. I’ve not needed this yet but I can see that being able to disable monitoring for a particular virtual host is a very useful option.

    Comment by squinney — March 17, 2008 @ 10:47 am


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