client.rb

# Chef Client Config File
# Automatically grabs configuration from ohai ec2 metadata.

require 'ohai'
require 'json'

o = Ohai::System.new
o.all_plugins
chef_config = JSON.parse(o[:ec2][:userdata])
if chef_config.kind_of?(Array)
  chef_config = chef_config[o[:ec2][:ami_launch_index]]
end

log_level        :info
log_location     STDOUT
chef_server_url  chef_config["chef_server"]
registration_url chef_config["chef_server"]
openid_url       chef_config["chef_server"]
template_url     chef_config["chef_server"]
remotefile_url   chef_config["chef_server"]
search_url       chef_config["chef_server"]
role_url         chef_config["chef_server"]
client_url       chef_config["chef_server"]

node_name        o[:ec2][:instance_id]

unless File.exists?("/etc/chef/client.pem")
  File.open("/etc/chef/validation.pem", "w") do |f|
    f.print(chef_config["validation_key"])
  end
end

if chef_config.has_key?("attributes")
  File.open("/etc/chef/client-config.json", "w") do |f|
    f.print(JSON.pretty_generate(chef_config["attributes"]))
  end
  json_attribs "/etc/chef/client-config.json"
end

validation_key "/etc/chef/validation.pem"
validation_client_name chef_config["validation_client_name"]

Mixlib::Log::Formatter.show_time = true

example.json

{
  "attributes": {
    "run_list": [
      "recipe[foo]",
      "role[bar]"
    ]
  },
  "validation_key": "-----BEGIN RSA PRIVATE KEY-----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\nwirursGexJa5Sdapio9VZnjkc2XSIDQkySdNNjfpGeF9A7xlIP17DQ==\n-----END RSA PRIVATE KEY-----\n",
  "validation_client_name": "chef-validator",
  "chef_server": "http:\/\/localhost:4000"
}