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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

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3 Answers 3

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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.

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  • Ok, so do I need to have ec2 tools installed on each node (via puppet) to get tags or can I just get instance names via facter and then process them into tags before they will be used in puppetmaster ? Commented Jun 27, 2013 at 13:36
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    You dont need ec2 tools installed, you only need curl. You should learn how to write your own facts, really comes in handy http://docs.puppetlabs.com/guides/custom_facts.html Commented Jun 27, 2013 at 14:04
  • @PiotrJasiulewicz added description of custom fact creation. Commented Jun 27, 2013 at 14:45
  • Yes, found custom facts from my research, this all seams to be straight forward, but how do I go from having the instanceid in facter on the node, to having a tag name from the instance on pupeptmaster? If I have 20 instance id's still hard to classify on that. Commented Jun 28, 2013 at 10:26
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    Instance ID was used as an example of how to create a custom fact. Ammend the address curl uses to get something from user-data that you use to differential server type. Commented Jun 28, 2013 at 11:24
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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

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    Tags seem to be missing from the available facts though. That's a shame as it seems none of the other facts are user-configurable. I guess we still can't use this as a makeshift ENC. Commented Apr 26, 2014 at 22:49
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I agree with Sirch that at this point custom facts seem to be the way to go. AWS describe using Cloud formation facts at:

https://s3.amazonaws.com/cloudformation-examples/IntegratingAWSCloudFormationWithPuppet.pdf

Which is an interesting, if difficult read. The custom fact from it is:

# cfn.rb require 'rubygems' require 'json' filename = "/var/lib/cfn-init/data/metadata.json" if not File.exist?(filename) return end parsed = JSON.load(File.new(filename)) parsed.default = Hash.new parsed[\"Puppet\"].each do |key, value| actual_value = value if value.is_a? Array actual_value = value.join(',') end Facter.add(\"cfn_\" + key) do setcode do actual_value end end end

They then configure their nodes like:

node basenode { include cfn } node /^.*internal$/ inherits basenode { case $cfn_roles { ...cloud formation include... } }

I'm more inclined to implement this via hiera like:

--- :backends: - yaml :yaml: :datadir: /etc/puppet/hiera :hierarchy: - "roles/%{::cfn_roles}" - common

Then have something like common.yaml:

classes: cfn # or whatever your custom fact class is

roles/dbserver.yaml:

classes: mysql

roles/webserver.yaml:

classes: httpd httpd::port: 8080 ...

Jeff

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