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A knife exec script to change Chef node's name.
#!./bin/knife exec
# A knife exec script to change chef node's name, preserving all the attributes.
#
# Usage: knife exec rename-node.rb old-name new-name
#
# Script retrieves the Node object, changes its 'name' attribute,
# creates new Node object with updated name and rest of attributes
# untouched. Then it deletes old Node and Client objects from
# database, and logs into the server to update it:
# - copy validation.pem from the local .chef directory
# - remove client.pem
# - comment out node_name from client.rb
# - delete "name":"[^"]*" entry from attributes.json if file exists
# - delete attributes.json if empty
# - run chef-client -N new_id to re-register client
#
# Script makes a few assumptions that may be different in your setup:
# - that you keep validation.pem locally in .chef/
# - that you generate client.rb including client_name during chef-client run
# - that you may have attributes.json file and it is not pretty-printed (no extra spaces)
# - that chef-client will run with or without attributes.json file
#
# To sum up, you will probably want to review the script and adapt
# parts of it to match your setup, especially shell script part near
# the bottom (here-doc for ssh.exec! invocation).
#
# Based on:
# - http://tech.superhappykittymeow.com/?p=292
# - http://help.opscode.com/discussions/questions/130-rename-a-node
# - http://lists.opscode.com/sympa/arc/chef/2011-05/msg00196.html
abort("usage: ./bin/knife exec #{ARGV[1]} from_id to_id") unless ARGV[3]
require 'net/ssh'
require 'net/scp'
from_id = ARGV[2]
to_id = ARGV[3]
puts "Loading node #{from_id}..."
orig_node = Chef::Node.load(from_id)
node_data = JSON::parse(orig_node.to_json, :create_id => nil)
puts "Changing name attribute to #{to_id}..."
node_data['name'] = to_id
node_data.values.
select { |v| v.is_a?(Hash) and v['name'] }.
each { |v| v['name'] = to_id }
puts "Saving modified node..."
# without :create_id => nil JSON::parse will create an actual instance
new_node = JSON::parse(JSON::dump(node_data))
new_node.save
unless ENV['KEEP_IT_SAFE']
puts "Deleting node #{from_id}..."
orig_node.destroy
puts "Deleting client #{from_id}..."
Chef::ApiClient.load(from_id).destroy
end
puts "Logging into node..."
Net::SSH.start(new_node.ec2.public_hostname, Chef::Config[:knife][:ssh_user]) do |ssh|
puts "Uploading validation.pem..."
ssh.scp.upload!(".chef/validation.pem", "/tmp/validation.pem")
puts "Running update script..."
ssh.exec! <<EOF do |ch, stream, data|
set -e -x
cd /etc/chef
sudo mv -v /tmp/validation.pem .
sudo rm -v client.pem
sudo sed -i~rename '/node_name/s/^/# /' client.rb
if [ -f attributes.json ] ; then
sudo sed -i~rename 's/"name":"[^"]*",*//' attributes.json
[ `sudo cat attributes.json` = '{}' ] && sudo rm -v attributes.json
[ -f attributes.json ] && sudo cat attributes.json
fi
sudo chef-client -N #{to_id} -l warn
EOF
if stream == :stderr
STDERR.write data
STDERR.flush
else
STDOUT.write data
STDOUT.flush
end
end
end
puts "Done!"
exit 0
# http://wiki.opscode.com/display/chef/Knife+Exec#KnifeExec-PassingArgumentstoKnifeScripts
### Copyright (C) 2012 Maciej Pasternacki <maciej@pasternacki.net>
###
### DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
### Version 2, December 2004
###
### Copyright (C) 2004 Sam Hocevar <sam@hocevar.net>
###
### Everyone is permitted to copy and distribute verbatim or modified
### copies of this license document, and changing it is allowed as long
### as the name is changed.
###
### DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
### TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
###
### 0. You just DO WHAT THE FUCK YOU WANT TO.
@gilles

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gilles commented Jun 14, 2013

#53 fails with NoMethodError: undefined method `save' for #<Hash... (maybe it's a chef 11 thing)

The fork by @iroller (https://gist.github.com/iroller/5194657) has the fix

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