Amazon AWS EC2 + Puppet, get Puppet to know AWS instance tags

I am having a problem with my AWS deployment, fairly new to AWS and Puppet.

So coming to my question - can you distinguish puppet nodes with AWS machine tags or CNAME domains?

A little background about the plan:

have multiple clusters of machines, one php cluster, one legacy php cluster, one java cluster, one perl cluster
control configuration with puppet - still pretty new to puppet but as a developer I like the idea of being able to version control configuration of servers
have autoscaling enabled on those clusters - obviously the main benefit of the cloud that makes the much hight cost when it comes to any reasonable performance worth it (those amazon machines are slower than my phone...)
deployment controlled by Capistrano, this makes things a lot easier

So in AWS you get those super nasty public/private machine dns's... no way you can identify machines on those. In order to easer the problem, seams like AWS want's you to tag everything - so I did. Found a script that makes a CNAME record for each machine with the tag "ShortName" thanks to the Route53 API.

Every machine has a ShortName tag that becomes its CNAME, unfortunately puppet still resolves the private dns name.

I'd like to have

node 'perl-cluster'{}

in puppet, anyone any clue ho to achieve this?

Thanks

The way I've done it is to write a custom fact for the server to identify its role from user data, which can be accessed on 169.254.169.254, see your own user data...

AWS user-data documentation

curl http://169.254.169.254/latest/

so when I type facter role ill get 'dbserver', 'webserver' whatever, then use that to define a node, its important not to have autoscaling groups care the slightest about what the name of the server is.

/etc/puppet/manifests/nodes.pp

node default{
  include nodes::type
}

/etc/puppet/modules/nodes/manifests/init.pp

import “type.pp”

/etc/puppet/modules/nodes/manifests/type.pp

class nodes::type{
   case $role {
     “dbserver” : {
       include mysql
     }
   }
   case $role {
      “webserver” : {
       include httpd
     }
   }
}

/etc/puppet/manifests/modules.pp

 import nodes

I dont want to tell you exactly how to do it in your case, but here I'll show you how to create a custom fact to report the EC2 instance ID.

Facter, curl, are installed.

mkdir -p /home/ec2-user/lib/ruby/facter
export FACTERLIB=/home/ec2-user/lib/ruby/facter

cat > /home/ec2-user/lib/ruby/facter/instance_id < EOF
# instance_id.rb
#
require 'facter'
Facter.add("instance_id") do
    setcode "/usr/bin/curl -s http://169.254.169.254/latest/meta-data/instance-id"
    end
EOF

And lo, a custom fact was written.

Now I can use it to get the ec2 instance id:

$ facter instance_id
i-a1c0ffee

I dont have puppet installed on this machine, but if i wanted it available to puppet, id put in it /var/lib/puppet/lib/facter, and to distribute it to clients id ensure pluginsync=true in puppet.conf.

Bear in mind, all that ive said is highly subjective, its just how I do it, if theres a better way, I'd be interested.

As of facter 1.7 (released in April 2013), there are built-in facts that report various details of your EC2 instance.

Reference: http://docs.puppetlabs.com/facter/1.7/core_facts.html#ec2ec2-instance-data

Amazon AWS EC2 + Puppet, get Puppet to know AWS instance tags

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