[chef] Re: Re: Re: Passive recipes

[Adam Jacob < >]

On Tue, Oct 13, 2009 at 1:23 PM, Dan DeMaggio 
<
 >
 wrote:
>> This also means that you couldn't use the apache cookbook
>> on a system which didn't have the collectd cookbook.
>
> Exactly, but I want my recipes to be modular.

My instinct is to put this stuff in a collectd cookbook, rather than
have the apache cookbook embed collectd resources.

>> 2) Check the node's variables in the collectd config templates and only
>> enable the config you need.
>> <% if @node[:mysql] -%>
>
> The problem is that you have no idea if the MySQL recipe is called or
> not .. You only have the attributes, which are always defined. So you
> will always copy the collectd-mysql config file, even if MySQL is not
> going to be installed.
>
>> Would love to have a better solution to this problem.
>
> Looks like light weight resources/providers might help, but I'm still
> trying to wrap my head around them.

I would set a node attribute in the recipe itself, in an innocuous
enough namespace, and then use that attribute in the
collectd/munin/etc recipes see what should be configured.
Essentially, you're sending a message to yourself, saying "please
monitor/trend this".

Something like:

###
# Apache Recipe
###

node.set[:monitor][:apache2] = true

###
# Collectd Recipe
###

if node[:monitor][:apache2]
... do some stuff to enable ...
else
... do some stuff to disable ...
end

if node[:monitor][:mysql]
... do some stuff ...
end

####

The basic gist is, if the recipe is applied, then you should monitor
it.  You can also do this:

if node.recipe?('apache2')
end

And avoid setting an attribute altogether.

In either case, you'll want to make sure that the collectd recipe
comes last in the run list.

Adam

-- 
Opscode, Inc.
Adam Jacob, CTO
T: (206) 508-7449 E: