[chef] Re: how to set up cluster that has dependencies?

[Aaron Abramson < >]

The best thing to do would be to go through one of the getting-started 
tutorials: http://help.opscode.com/kb/otherhelp/build-a-lamp-stack

Watch that, follow along and deploy it yourself (if you have access to EC2), 
or just read through it.  It will give you a good idea on how nodes can query 
and search within templates.

Look through the php-quick-start repo, the haproxy cookbook searches chef for 
the apache nodes and updates the templates accordingly.

----- Original Message -----
From: "jeff stroomer" 
<
 >
To: 

 
Sent: Wednesday, September 21, 2011 7:00:17 PM GMT -06:00 US/Canada Central
Subject: [chef] how to set up cluster that has dependencies?

Chef folks,

I have a question concerning the best way to use Chef to set up a cluster of
nodes that have dependencies on one another. (Apologies in advance if this is 
a
naïve question, but I’m new to Chef.)

For concreteness, suppose I want node  V  to run varnish, node T to run 
tomcat,
and node  M to run mongo.  And let’s say that T needs to know the IP address
of M, and V needs to know the IP address of T.  I believe  that each node can
register its IP address in a database maintained on the Chef server, and
recipes run by each node can query this database.  For things to work 
properly,
I ought to set up M first, then T, and finally V.  

My question is this: How I should plan to use Chef so that the setup of 
various
nodes happens in the right order?  Do  I write a recipe that sets up M first,
then T, and finally V?   If so, then what is that recipe associated to?  Or
should I instead have a recipe for V that sets up T, and also  have the setup
recipe for T begin by setting up M?  Or should I write recipes for T, M, and V
that query the database, and don’t do anything unless they can find the IP
addresses they need?

Jeff